ABSTRACT
The Taurus Molecular Cloud subtends a large solid angle on the sky, in excess of 250 deg2. The search for legitimate Taurus members to date has been limited by sky coverage as well as the challenge of distinguishing members from field interlopers. The Wide-field Infrared Survey Explorer has recently observed the entire sky, and we take advantage of the opportunity to search for young stellar object (YSO) candidate Taurus members from a ∼260 deg2 region designed to encompass previously identified Taurus members. We use near- and mid-infrared colors to select objects with apparent infrared excesses and incorporate other catalogs of ancillary data to present a list of rediscovered Taurus YSOs with infrared excesses (taken to be due to circumstellar disks), a list of rejected YSO candidates (largely galaxies), and a list of 94 surviving candidate new YSO-like Taurus members. There is likely to be contamination lingering in this candidate list, and follow-up spectra are warranted.
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1. INTRODUCTION
In recent years, there have been many infrared (IR) studies of nearby star-forming regions with the Spitzer Space Telescope (Werner et al. 2004). Since most, if not all, low-mass stars form with circumstellar accretion disks, they have IR excesses for as long as the dusty circumstellar material survives (e.g., Hernandez et al. 2008). Stars with large IR excesses are relatively easily distinguished from stars without such excesses, while stars with more modest excesses require more accurate knowledge of the underlying star and the intervening extinction. Surveys with Spitzer have proven very good at finding new young stars in star-forming regions, some located surprisingly far from the traditional locations of star formation based on CO gas or IRAS dust maps. However, even though Spitzer is able to survey large areas relatively quickly, it still is a pointed observatory and cannot easily conduct a truly wide-field survey. In very close star-forming regions such as Taurus, the large solid angle subtended by the association challenges the search for new members, rendering the samples incomplete, particularly for a distributed population. See, however, Rebull et al. (2010).
We conducted a ∼44 deg2 survey of Taurus with Spitzer, using 3.6, 4.5, 5.8, 8, 24, 70, and 160 μm (D. L. Padgett et al. 2011, in preparation; Padgett et al. 2008b; Güdel et al. 2007b). In Rebull et al. (2010), we reported on our search for new young stellar objects (YSOs) in Taurus. We used a primarily Spitzer-driven color selection, but took advantage of considerable ancillary data amassed in the service of a multi-wavelength search for new young stars. We found that any solely near- and mid-infrared color selection was filled with contamination from galaxies and asymptotic giant branch (AGB) stars, and that use of ancillary data was crucial to establishing a list of high-quality new members of Taurus. We now use our experience with this prior data set to inform our selection using the Wide-field Infrared Survey Explorer (WISE; Wright et al. 2010) data.
WISE conducted an all-sky survey in 2009–2011. These data are well-suited to studying nearby star-forming clouds such as Taurus, where members are likely to be bright because of their proximity to us as well as their youth, and well within the regime of good signal-to-noise ratio (S/N) WISE photometry. Furthermore, the all-sky nature of the survey allows us to look away from the more traditional and well-studied clustered regions and include some young stars in the direction of Taurus (not necessarily Taurus members) that were never studied with Spitzer.
WISE surveyed the entire sky, but the depth of coverage is non-uniform and generally greater at higher ecliptic latitudes (Taurus is in the ecliptic plane). The depth of coverage in the Taurus region is somewhat degraded relative to regions of comparable ecliptic latitude due to Moon avoidance maneuvers made during the mission. Most of the Taurus region is observed to a depth of about 0.08, 0.11, 0.8, and 6 mJy in the four bands (5σ, given eight visits), and we further restrict the depth with S/N cuts; see below. Our original Taurus Spitzer Survey went to 0.06, 0.06, 0.14, and 1.1 mJy for IRAC-1 (3.6 μm), IRAC-2 (4.5 μm), IRAC-4 (8 μm), and MIPS-24 (24 μm), respectively. However, both surveys should easily detect legitimate Taurus members, since the cloud is only 140 pc away.
In this paper, we select new candidate Taurus members with infrared excesses using WISE colors using the method established in Koenig et al. (2011). We compare the list of selected objects to catalogs we have assembled from our prior work and updated. We report three lists—recovered young stars, rejected objects, and candidate new Taurus members. The observations and basic data handling are described in Section 2, Section 3 describes how we identified our YSO candidates, Section 4 presents some global properties of the ensemble of YSO candidates, with a special focus on estimating the degree of contamination, and finally we summarize in Section 5.
2. OBSERVATIONS, DATA REDUCTION, AND ANCILLARY DATA
In the context of Rebull et al. (2010), we assembled a substantial multi-wavelength database, spanning Sloan u through Spitzer/MIPS 160 μm (with some X-rays) for point sources throughout the Taurus region. We note that not every source has photometry at all bands due to variations in depth and spatial coverage among the surveys involved. We use that catalog as the core for our analysis here, updating it with confirmed Taurus members from, e.g., Kenyon et al. (2008) and Luhman et al. (2010) outside of our original Spitzer map. We have also searched SIMBAD (and literature references therein) for known galaxies and other contaminants such as planetary nebulae (PNe) in this vicinity and considered these identifications in our analysis of the WISE photometry.
Our Taurus Spitzer Survey spanned ∼44 deg2; see Figure 1. Notably, two of the surveys we assembled at other wavelengths extend well beyond the region we mapped with Spitzer—the CO(1–0) radio map (Goldsmith et al. 2008) and two Sloan Digital Sky Survey (SDSS) stripes. Goldsmith et al. (2008) mapped ∼100 deg2; see Figure 1. The SDSS (Finkbeiner et al. 2004; Padmanabhan et al. 2008) initially mapped the Taurus region in two perpendicular strips covering ∼48 deg2, overlapping in part with the Goldsmith et al. (2008) and our Spitzer maps, but extending further east–west and substantially further north. Additional SDSS strips substantially increased the area observed; see Figure 1. We note that the unfilled stripe that crosses the region diagonally is one of the photometric calibration stripes a la Padmanabhan et al. (2008). Further motivating consideration of a wider area, the XMM-Newton Extended Survey of the Taurus Molecular Cloud program (Güdel et al. 2007a, and references therein) mapped ∼5 deg2, most but not all of which was covered by our Spitzer maps. Finally, as seen in Figure 1, Kenyon et al. (2008) include a list of known Taurus members, many of which are well beyond the bounds of our original Spitzer survey, and Slesnick et al. (2006) report on several more candidate Taurus members.
Figure 1. Location in the sky of the various surveys discussed here. Solid black box: boundary of Goldsmith et al. (2008) CO(1–0) survey; gray-colored regions: SDSS coverage; smaller irregular black dotted polygon: coverage of Spitzer Taurus Survey (D. L. Padgett et al. 2011, in preparation; Padgett et al. 2008b; Güdel et al. 2007b); red dash-dotted line: boundary of polygon extracted from WISE catalog; + symbols: Taurus members from Kenyon et al. (2008); diamonds: proposed Taurus members from Slesnick et al. (2006).
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Standard image High-resolution imageWe define a polygon in which we searched for YSO candidates using WISE that encompasses all of the members from Kenyon et al. (2008), a few of the potential members from Slesnick et al. (2006), and all of the Sloan coverage to the north of our previous Spitzer survey. The R.A./decl. vertices of this polygon are in degrees: 77.4 31, 77.4 20.5, 74 20.5, 74 16.5, 66 16.5, 66 15, 64 15, 64 19.8, 59.5 19.8, 57.7 24.5, 58.5 32.3, 63.8 32.3, 63.8 37, 66.8 37, 66.81 32.93, 77.30 32.77. The total area we have considered is ∼260 deg2.
This area is so large that we need to consider other star-forming regions very nearby (in projection) to Taurus. Figure 2 shows our polygon on an IRAS 100 μm image of the region. NGC 1579 is the bright knot in the central north of the image; this is thought to be 700 pc away (Herbig et al. 2004), too far to be part of Taurus at 140 pc. Lynds 1548 and environs will be discussed in a forthcoming paper by W. Liu et al. (2012, in preparation). Our polygon intersects with the tidal radius of the Pleiades (∼6°; Adams et al. 2001). Young objects identified within our polygon and within ∼6°of the Pleiades could belong to the Pleiades and not Taurus.
Figure 2. Overlaid on an IRAS 100 μm map, the location in the sky of our survey contour (red polygon), other nearby star-forming regions of interest, and the tidal radius of the Pleiades (green circle). L1548 will be discussed by W. Liu et al. (2012, in preparation). Some of our objects are within the tidal radius of the Pleiades and thus perhaps could be members of the Pleiades rather than Taurus. NGC 1579 is centered on the bright spot.
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Standard image High-resolution imageWISE data acquisition and reduction are discussed in Wright et al. (2010), Jarrett et al. (2011), and in the Explanatory Supplement to the WISE Preliminary Data Release Products. There are four WISE bands, with central wavelengths at 3.4, 4.6, 12, and 22 μm, and a spatial resolution of 6'' (12'' at 22 μm). The four bands are often referred to as W1, W2, W3, and W4. We rejected any source with contamination and confusion flags ("cc_flags" in the catalog) that include any of the characters "DHOP" in its four-character string as likely contamination or confusion artifacts.11 This process resulted in a catalog containing about 2.38 million sources. The WISE catalog reports S/Ns. We further restricted ourselves to those measurements with S/N > 7 in all four bands, drastically shrinking the catalog to ∼7000 sources. Our initial attempts limited the analysis to those measurements with S/N > 7 in just the first three bands, but given the expected brightness of Taurus members, plus the contamination rate we expect based on our experience with Spitzer in Taurus, we opted to enforce the S/N cut in W4 as well so as to limit the contamination in our list of candidate YSOs.
The WISE catalog reports flux measurements in magnitudes with errors in magnitudes, and the source selection in this paper was based on these magnitudes. The zero points we used to convert between magnitudes and flux densities in the spectral energy distribution (SED) plots included in the complete figure set of Figure 12 in the Appendix are 309.54, 171.79, 31.676, and 8.3635 Jy for the four channels, respectively, based on the zero points in Wright et al. (2010) and the flux correction factors for a spectrum with constant Fν. These zero points are also used by Jarrett et al. (2011).
The WISE bands are merged among themselves and to the Two Micron All Sky Survey (2MASS; Skrutskie et al. 2006) in the data products provided by the WISE archive housed at the Infrared Science Archive. We merged this catalog to our already-assembled catalog of ancillary data via a strictly position-based search with a 1'' radius. As noted in Section VI.5.f of the WISE Explanatory Supplement, the WISE catalog reports positions of sources brighter than W1< 13.0 mag to 0.2 arcsec (1σ) relative to 2MASS positions. The positions reported for fainter sources may suffer from a systematic error up to 1'' in declination due to a pipeline coding error.
3. IDENTIFYING THE YSO CANDIDATES
The process of identifying the YSO candidates is a multi-step process, beginning with color cuts and progressing through ancillary data, including manual checks of SEDs and images. We now describe the process that we used.
3.1. Initial Cut
We started with our extracted WISE catalog over the ∼260 deg2 polygon specified above and applied the color cuts discussed in Koenig et al. (2011). In summary, there are a series of cuts in multiple color spaces based on the location of previously identified YSOs and galaxies. These are intended statistically to weed out most contaminants and find most YSOs. No color cuts can perform this task flawlessly, though many have been discussed in the literature in the context of Spitzer observations (e.g., Allen et al. 2004; Padgett et al. 2008a; Rebull et al. 2007, 2010, 2011; Harvey et al. 2007; Gutermuth et al. 2008, 2009). As discussed in Rebull et al. (2010), especially over very large fields like Taurus, where the molecular cloud does not block out most background sources and where the survey area is big enough that the chances of obtaining more unusual objects are greater, the contamination rate for any color selection is expected to be relatively large, and ancillary data are crucial for culling the list to high-quality candidates.
The color cuts described in Koenig et al. (2011) are inspired by Gutermuth et al. (2008, 2009) and Rebull et al. (2010) and applied using WISE+2MASS colors. For their full selection process, Koenig et al. (2011) estimate a contamination rate for "typical" star-forming regions of about 2.4 objects resembling Class Is, 3.8 objects resembling Class IIs, and 1.8 objects resembling transition disks per square degree. At this rate, with our ∼260 deg2 map, we expect ∼620, ∼990, and ∼470, respectively, for a rough total of ∼2000 contaminants per square degree. As a check, we recalculated these contamination rates for a ∼10 deg2 patch at the north and south equatorial poles, and obtained values between ∼1500 and ∼1600 contaminants per square degree. However, these values are sensitive to relative depths of WISE coverage (deeper at the poles than the ecliptic), any bright extended emission in the image (present here but less so in the extragalactic fields), and natural variability in the space density of stars and galaxies.
We initially applied the Koenig et al. method to the WISE catalog where the S/N is at least 7 in channels 1, 2, and 3, but not necessarily 4. We thus obtained ∼1760 YSO candidates. Given the contamination rates expected above, we thus anticipate a high fraction of contaminants in this list. As mentioned above, given the expected brightness of Taurus members, plus the contamination rate we expect based on our experience with Spitzer in Taurus, we chose to impose an S/N cut in W4 as well so as to limit the contamination in our list of candidate YSOs. Imposing our additional requirement that the S/N is at least 7 in all four WISE channels results in a pool of 1014 potential YSOs.
3.2. Ancillary Data
We know from our Spitzer search for new members of Taurus that ancillary data are very important for weeding the contaminants out from the list of potential YSO candidates. So, in addition to our catalog above, we have included the information from ancillary data in our assembly of our final YSO candidate list in an effort to limit the contamination.
We have matched our WISE catalog to the full SDSS catalog (from DR8) in this region (which includes extended source information from the images) and the 2MASS Extended Source Catalog. Objects that are extended are likely to be (though are not guaranteed to be) galaxies; see the discussion in Rebull et al. (2010). There are also ∼11,500 SDSS spectra in the SDSS stripes; just 27 of the sources in our list of potential YSOs find matches with SDSS spectra.
We merged to the Akari 9 and 18 μm Infrared Camera (IRC) all-sky point-source catalog (Ishihara et al. 2010). There are ∼3000 sources in this region, ∼100 of which match to the WISE-selected sources, ∼80% of which are for previously known Taurus members.
Based on our experience with our Taurus Spitzer Survey, we know that the YSOs are generally though not exclusively found in regions of high AV. Thus, we expect that an estimate of AV toward our new candidates in this larger region will also be useful in weeding out contaminants. Froebrich et al. (2007) report on a large, 127 × 63 deg2 extinction map based on 2MASS data. We used this map to estimate AV toward our list of candidates. This map is calculated to a ∼4' resolution, and we used a 3×3 pixel (6' × 6') median calculated about the position of each source to estimate the AV.
3.3. Previously Identified YSOs
For the 1014 potential YSOs selected from WISE+2MASS color and magnitude cuts imposed on the 2.38 million sources with good S/N photometry, 196 of them have matches to previously identified stars with indications of youth and/or infrared excesses, in the direction of Taurus. Table 1 lists these objects and their WISE measurements. Most of the objects in Table 1 are previously identified explicitly as Taurus members in Güdel et al. (2007a) and references therein, Kenyon et al. (2008), Rebull et al. (2010), and/or Luhman et al. (2010). Eighteen of the objects in Table 1 are listed as unconfirmed candidates in Rebull et al. (2010); these are identified as such in the "notes" column of Table 1. (As discussed in Rebull et al. 2010, for these objects, we could not find unambiguous spectroscopic indications of youth—such as the Hα emission line was low or absent—so additional data are needed to confirm or refute these objects as Taurus members. These objects should not be regarded as Taurus members with the same confidence as, e.g., DG Tau, but they are not necessarily clearly field interlopers either.) The candidates from Slesnick et al. (2006) would have been similarly indicated, except they are largely not recovered, save for three objects commonly taken as Taurus members (SCHJ0429595+2433080 = CFHT-20, SCHJ0438586+2336352 = J0438586+2336352, and SCHJ0439016+2336030 = J0439016+2336030). Eight of the objects in Table 1 are not traditionally identified as Taurus members, but we recover them as having IR excess, and they appear in the literature as having some indications of youth and with appropriate proper motions for Taurus members (2MASS J04360131+1726120, 2MASS J04324107+1809239, HD 285893, HBHA 3214-06, GZ Aur, BS Tau, IRAS 05020+2518, HO Aur). These are also indicated in Table 1 in the "notes" column.
Table 1. Multiband Measurements of WISE-identified YSOs with Previous Indications of Youth in the Literature towards the Taurus Regiona
| Line | Catalog Number | Name | W1 (3.4 μm) | W2 (4.6 μm) | W3 (12 μm) | W4 (22 μm) | Notes |
|---|---|---|---|---|---|---|---|
| Num. | (mag) | (mag) | (mag) | (mag) | |||
| 1 | J040443.06+261856.3 | IRAS 04016+26102 | 7.67 ± 0.03 | 5.16 ± 0.03 | 2.91 ± 0.02 | 0.01 ± 0.02 | |
| 2 | J041339.46+292113.8 | None | 12.78 ± 0.03 | 11.74 ± 0.02 | 9.43 ± 0.04 | 7.40 ± 0.11 | Still a candidate YSOb |
| 3 | J041353.28+281123.1 | IRAS 04108+2803 A | 9.44 ± 0.02 | 8.28 ± 0.02 | 5.47 ± 0.02 | 3.60 ± 0.02 | |
| 4 | J041354.70+281132.6 | IRAS 04108+2803 B | 9.44 ± 0.02 | 7.36 ± 0.02 | 4.33 ± 0.02 | 1.46 ± 0.01 | |
| 5 | J041357.37+291819.1 | IRAS 04108+2910 | 8.00 ± 0.02 | 6.98 ± 0.02 | 4.96 ± 0.02 | 2.97 ± 0.02 | |
| 6 | J041412.29+280837.1 | IRAS 04111+2800G | 13.86 ± 0.03 | 11.73 ± 0.03 | 8.97 ± 0.03 | 4.03 ± 0.02 | |
| 7 | J041412.91+281212.3 | V773 Tau ABC | 6.64 ± 0.02 | 5.87 ± 0.02 | 3.87 ± 0.02 | 1.91 ± 0.01 | |
| 8 | J041413.58+281249.0 | FM Tau | 8.07 ± 0.02 | 7.48 ± 0.02 | 5.21 ± 0.02 | 3.03 ± 0.03 | |
| 9 | J041414.59+282757.9 | FN Tau | 7.48 ± 0.03 | 6.78 ± 0.02 | 4.09 ± 0.02 | 1.96 ± 0.02 | |
| 10 | J041417.61+280609.5 | CIDA-1 | 9.05 ± 0.02 | 8.17 ± 0.02 | 5.49 ± 0.02 | 3.56 ± 0.03 | |
| 11 | J041426.31+280601.9 | MHO-1 | 6.16 ± 0.04 | 4.81 ± 0.03 | 2.79 ± 0.02 | 0.44 ± 0.01 | |
| 12 | J041430.55+280514.4 | MHO-3 | 6.95 ± 0.03 | 5.70 ± 0.03 | 2.58 ± 0.02 | 0.24 ± 0.02 | |
| 13 | J041447.30+264626.3 | FP Tau | 8.39 ± 0.02 | 7.95 ± 0.02 | 6.47 ± 0.02 | 4.43 ± 0.03 | |
| 14 | J041447.86+264810.9 | CX Tau | 8.51 ± 0.02 | 8.04 ± 0.02 | 5.65 ± 0.02 | 3.45 ± 0.02 | |
| 15 | J041449.28+281230.4 | FO Tau AB | 7.42 ± 0.03 | 6.91 ± 0.02 | 5.11 ± 0.02 | 3.05 ± 0.02 | |
| 16 | J041535.66+284741.3 | None | 13.61 ± 0.03 | 12.00 ± 0.03 | 9.29 ± 0.04 | 5.84 ± 0.04 | Still a candidate YSOb |
| 17 | J041539.16+281858.3 | 041539.1+281858 | 8.77 ± 0.02 | 8.33 ± 0.02 | 6.86 ± 0.02 | 4.44 ± 0.03 | |
| 18 | J041542.77+290959.1 | 041542.7+290959 | 9.04 ± 0.02 | 8.91 ± 0.02 | 8.57 ± 0.03 | 4.76 ± 0.02 | |
| 19 | J041558.00+274617.2 | 041557.9+274617 | 9.85 ± 0.02 | 9.33 ± 0.02 | 7.47 ± 0.02 | 5.86 ± 0.04 | |
| 20 | J041604.83+261800.9 | None | 12.36 ± 0.03 | 11.28 ± 0.02 | 8.68 ± 0.03 | 6.61 ± 0.07 | Still a candidate YSOb |
| 21 | J041612.10+275638.3 | J04161210+2756385 | 9.47 ± 0.03 | 8.86 ± 0.02 | 7.68 ± 0.02 | 5.56 ± 0.04 | |
| 22 | J041639.12+285848.8 | J04163911+2858491 | 10.58 ± 0.02 | 10.07 ± 0.02 | 8.86 ± 0.03 | 7.29 ± 0.12 | (SDSS spectrum: STAR -M8) |
| 23 | J041749.55+281331.5 | KPNO-10 | 11.38 ± 0.02 | 10.55 ± 0.02 | 8.01 ± 0.02 | 6.04 ± 0.05 | (SDSS spectrum: STAR -M6) |
| 24 | J041749.65+282936.0 | V410 X-ray 1 | 8.43 ± 0.02 | 7.76 ± 0.02 | 5.49 ± 0.02 | 3.83 ± 0.03 | |
| 25 | J041803.37+244009.6 | 041803.3+244009 | 10.01 ± 0.03 | 10.01 ± 0.02 | 9.39 ± 0.04 | 7.33 ± 0.11 | Still a candidate YSOb |
| 26 | J041810.60+284447.0 | None | 12.66 ± 0.03 | 11.59 ± 0.02 | 9.11 ± 0.04 | 6.58 ± 0.07 | Still a candidate YSOb |
| 27 | J041810.78+251957.2 | [GBM90]L15061 | 8.32 ± 0.02 | 7.93 ± 0.02 | 5.54 ± 0.02 | 3.81 ± 0.02 | |
| 28 | J041817.10+282841.6 | V410 Anon 13 | 10.52 ± 0.03 | 9.84 ± 0.02 | 7.97 ± 0.02 | 6.15 ± 0.05 | |
| 29 | J041823.20+251928.0 | 2MASX04182321+2519281 | 11.92 ± 0.03 | 10.90 ± 0.02 | 8.43 ± 0.03 | 6.28 ± 0.05 | Still a candidate YSOb |
| 30 | J041831.12+281628.8 | DD Tau AB | 6.83 ± 0.03 | 5.78 ± 0.02 | 3.72 ± 0.02 | 1.80 ± 0.02 | |
| 31 | J041831.60+281658.3 | CZ Tau AB | 8.65 ± 0.02 | 7.49 ± 0.02 | 3.85 ± 0.02 | 2.13 ± 0.02 | |
| 32 | J041832.03+283115.1 | IRAS 04154+2823 | 7.78 ± 0.02 | 6.52 ± 0.02 | 4.28 ± 0.02 | 1.99 ± 0.02 | |
| 33 | J041834.44+283030.0 | V410 X-ray 2 | 8.65 ± 0.02 | 8.01 ± 0.02 | 6.72 ± 0.02 | 3.58 ± 0.02 | |
| 34 | J041841.32+282724.7 | LR1 | 9.98 ± 0.02 | 8.93 ± 0.02 | 7.48 ± 0.03 | 4.82 ± 0.03 | |
| 35 | J041851.47+282026.2 | CoKu Tau/1 | 10.27 ± 0.02 | 8.47 ± 0.02 | 3.84 ± 0.02 | 1.01 ± 0.02 | (SDSS spectrum: GALAXY-STARBURST) |
| 36 | J041858.07+235030.8 | None | 12.95 ± 0.03 | 11.78 ± 0.02 | 9.28 ± 0.04 | 7.41 ± 0.12 | Still a candidate YSOb |
| 37 | J041858.13+281223.1 | IRAS 04158+2805 | 9.47 ± 0.03 | 8.32 ± 0.02 | 5.70 ± 0.02 | 2.99 ± 0.02 | |
| 38 | J041858.99+255740.0 | None | 13.37 ± 0.03 | 11.98 ± 0.02 | 8.64 ± 0.03 | 6.06 ± 0.04 | Still a candidate YSOb |
| 39 | J041901.10+281941.8 | V410 X-ray 6 | 8.98 ± 0.03 | 8.64 ± 0.02 | 7.20 ± 0.02 | 3.89 ± 0.03 | |
| 40 | J041915.83+290626.6 | BP Tau | 7.08 ± 0.03 | 6.64 ± 0.02 | 4.78 ± 0.02 | 2.74 ± 0.02 | |
| 41 | J041935.46+282721.4 | FR Tau | 9.55 ± 0.03 | 8.77 ± 0.02 | 6.33 ± 0.02 | 4.86 ± 0.03 | |
| 42 | J041940.48+270100.7 | None | 13.16 ± 0.03 | 11.94 ± 0.03 | 9.21 ± 0.05 | 6.88 ± 0.10 | Still a candidate YSOb |
| 43 | J041941.49+271606.8 | HH390 star | 11.65 ± 0.03 | 10.36 ± 0.02 | 7.43 ± 0.02 | 3.25 ± 0.02 | |
| 44 | J041946.58+271255.0 | J04194657+2712552 | 10.81 ± 0.03 | 9.36 ± 0.02 | 7.05 ± 0.02 | 4.14 ± 0.03 | |
| 45 | J041958.45+270957.0 | IRAS 04169+2702 | 8.90 ± 0.02 | 6.96 ± 0.02 | 3.93 ± 0.02 | 0.81 ± 0.02 | |
| 46 | J042025.55+270035.4 | J04202555+2700355 | 11.19 ± 0.03 | 10.71 ± 0.02 | 8.64 ± 0.03 | 6.14 ± 0.06 | (SDSS spectrum: STAR -M7) |
| 47 | J042025.83+281923.5 | J04202583+2819237 | 9.45 ± 0.02 | 8.38 ± 0.02 | 6.01 ± 0.02 | 4.05 ± 0.03 | |
| 48 | J042026.06+280408.8 | J04202606+2804089 | 9.46 ± 0.03 | 9.07 ± 0.02 | 6.53 ± 0.02 | 3.73 ± 0.03 | |
| 49 | J042107.96+270220.3 | CFHT-19 | 8.02 ± 0.02 | 6.87 ± 0.02 | 4.22 ± 0.02 | 1.84 ± 0.02 | |
| 50 | J042110.39+270137.1 | IRAS 04181+2654B | 9.57 ± 0.02 | 8.12 ± 0.02 | 5.66 ± 0.02 | 2.87 ± 0.02 | |
| 51 | J042111.46+270109.3 | IRAS 04181+2654A | 9.03 ± 0.03 | 7.57 ± 0.02 | 4.84 ± 0.02 | 1.78 ± 0.02 | |
| 52 | J042143.23+193413.2 | 04187+1927 | 7.08 ± 0.03 | 6.14 ± 0.02 | 3.66 ± 0.02 | 1.94 ± 0.02 | |
| 53 | J042155.63+275505.9 | DE Tau | 7.07 ± 0.03 | 6.53 ± 0.02 | 4.86 ± 0.02 | 2.80 ± 0.03 | |
| 54 | J042159.44+193205.9 | TTau | 3.86 ± 0.06 | 2.20 ± 0.01 | 0.10 ± 0.00 | -2.13 ± 0.02 | |
| 55 | J042200.42+153021.2 | 2MASX04220037+1530212 | 10.51 ± 0.03 | 8.35 ± 0.02 | 5.34 ± 0.01 | 2.35 ± 0.03 | |
| 56 | J042247.87+264552.7 | IRAS 04196+2638 | 8.14 ± 0.02 | 7.36 ± 0.02 | 5.49 ± 0.07 | 3.27 ± 0.03 | |
| 57 | J042307.77+280557.1 | IRAS 04200+2759 | 8.80 ± 0.02 | 7.98 ± 0.02 | 5.52 ± 0.02 | 3.38 ± 0.03 | (SDSS spectrum: STAR -M2) |
| 58 | J042335.39+250302.5 | FUTau | 8.62 ± 0.02 | 7.85 ± 0.02 | 6.05 ± 0.02 | 4.65 ± 0.03 | (SDSS spectrum: STAR -M8) |
| 59 | J042444.58+261014.0 | IRAS 04216+2603 | 8.09 ± 0.02 | 7.36 ± 0.02 | 5.41 ± 0.02 | 3.49 ± 0.02 | |
| 60 | J042457.08+271156.2 | IP Tau | 7.75 ± 0.02 | 7.26 ± 0.02 | 5.38 ± 0.02 | 3.59 ± 0.03 | |
| 61 | J042519.16+234716.7 | HD27923 | 7.54 ± 0.03 | 7.57 ± 0.02 | 7.58 ± 0.02 | 1.33 ± 0.01 | Still a candidate YSOb |
| 62 | J042629.39+262413.4 | KPNO-3 | 11.56 ± 0.03 | 10.94 ± 0.02 | 8.76 ± 0.03 | 6.91 ± 0.09 | (SDSS spectrum: STAR -M8) |
| 63 | J042653.50+260654.1 | FV Tau AB | 6.78 ± 0.03 | 5.58 ± 0.02 | 3.21 ± 0.01 | 1.37 ± 0.01 | |
| 64 | J042656.25+244335.1 | IRAS 04239+2436 | 8.13 ± 0.02 | 6.05 ± 0.02 | 3.12 ± 0.02 | 0.17 ± 0.03 | |
| 65 | J042657.31+260628.1 | KPNO-13 | 8.94 ± 0.03 | 8.27 ± 0.02 | 6.50 ± 0.03 | 4.95 ± 0.08 | (SDSS spectrum: STAR -M7) |
| 66 | J042702.56+260530.4 | DGTauB | 8.97 ± 0.03 | 6.71 ± 0.02 | 3.41 ± 0.02 | 0.78 ± 0.02 | |
| 67 | J042702.79+254222.2 | DF Tau AB | 5.89 ± 0.05 | 5.03 ± 0.03 | 3.80 ± 0.02 | 2.31 ± 0.02 | |
| 68 | J042704.69+260615.9 | DG Tau A | 6.18 ± 0.04 | 4.98 ± 0.03 | 2.26 ± 0.01 | -0.19 ± 0.02 | |
| 69 | J042730.27+244123.6 | 2MASX04273023+2441232 | 11.75 ± 0.03 | 11.49 ± 0.03 | 8.35 ± 0.03 | 6.31 ± 0.10 | Still a candidate YSOb |
| 70 | J042757.31+261918.1 | IRAS 04248+2612 AB | 9.81 ± 0.02 | 8.75 ± 0.02 | 5.45 ± 0.02 | 2.35 ± 0.01 | |
| 71 | J042810.38+243553.7 | None | 13.99 ± 0.03 | 12.44 ± 0.03 | 9.79 ± 0.05 | 7.61 ± 0.16 | Still a candidate YSOb |
| 72 | J042842.62+271403.5 | J04284263+2714039 AB | 9.79 ± 0.02 | 9.37 ± 0.02 | 8.09 ± 0.03 | 6.18 ± 0.05 | |
| 73 | J042904.98+264907.1 | IRAS 04260+2642 | 10.57 ± 0.02 | 9.53 ± 0.02 | 7.00 ± 0.02 | 3.65 ± 0.02 | |
| 74 | J042920.82+274207.3 | IRAS 04262+2735 | 6.55 ± 0.04 | 6.34 ± 0.02 | 3.84 ± 0.02 | 3.02 ± 0.02 | |
| 75 | J042921.65+270125.7 | IRAS 04263+2654 | 8.27 ± 0.03 | 7.62 ± 0.02 | 5.77 ± 0.02 | 3.50 ± 0.02 | |
| 76 | J042923.73+243300.9 | GV Tau AB | 5.95 ± 0.04 | 3.24 ± 0.04 | 0.30 ± 0.00 | -1.63 ± 0.01 | (SDSS spectrum: GALAXY-STARBURST) |
| 77 | J042930.08+243954.9 | IRAS 04264+2433 | 10.28 ± 0.02 | 9.05 ± 0.02 | 4.35 ± 0.02 | 1.13 ± 0.01 | |
| 78 | J042932.08+243059.4 | None | 11.06 ± 0.03 | 9.20 ± 0.02 | 6.29 ± 0.02 | 4.04 ± 0.04 | |
| 79 | J042936.06+243555.4 | J04293606+2435556 | 8.12 ± 0.02 | 7.64 ± 0.02 | 6.39 ± 0.02 | 4.44 ± 0.03 | |
| 80 | J042941.55+263258.0 | DH Tau AB | 7.42 ± 0.03 | 6.99 ± 0.02 | 5.73 ± 0.02 | 3.07 ± 0.02 | |
| 81 | J042951.55+260644.7 | IQ Tau | 7.21 ± 0.03 | 6.67 ± 0.02 | 4.87 ± 0.02 | 3.01 ± 0.02 | |
| 82 | J042954.22+175403.8 | 04295422+1754041 | 10.12 ± 0.02 | 9.47 ± 0.02 | 8.13 ± 0.03 | 6.42 ± 0.06 | |
| 83 | J042959.50+243307.5 | CFHT-20 | 9.09 ± 0.02 | 8.45 ± 0.02 | 6.84 ± 0.02 | 4.88 ± 0.03 | (SDSS spectrum: STAR -M8) |
| 84 | J043003.99+181349.4 | UXTau | 6.99 ± 0.03 | 6.61 ± 0.02 | 5.69 ± 0.01 | 2.17 ± 0.02 | |
| 85 | J043029.62+242644.9 | FX Tau AB | 7.49 ± 0.03 | 7.09 ± 0.02 | 5.09 ± 0.02 | 3.23 ± 0.02 | |
| 86 | J043044.25+260124.4 | DK Tau AB | 6.12 ± 0.04 | 5.38 ± 0.03 | 3.59 ± 0.01 | 1.84 ± 0.01 | |
| 87 | J043051.38+244222.2 | ZZ Tau AB | 8.09 ± 0.02 | 7.66 ± 0.02 | 5.94 ± 0.02 | 4.33 ± 0.03 | |
| 88 | J043051.71+244147.4 | ZZ Tau IRS | 9.01 ± 0.02 | 7.16 ± 0.02 | 4.43 ± 0.02 | 1.95 ± 0.02 | |
| 89 | J043134.12+180804.9 | 2MASX04313407+1808048 | 7.75 ± 0.02 | 5.55 ± 0.02 | 0.86 ± 0.01 | -2.37 ± 0.01 | |
| 90 | J043136.14+181343.1 | LkHa358 | 8.17 ± 0.02 | 7.16 ± 0.02 | 4.96 ± 0.02 | 2.39 ± 0.03 | |
| 91 | J043138.42+181357.6 | HLTau | 5.42 ± 0.05 | 3.34 ± 0.03 | 1.52 ± 0.01 | -1.23 ± 0.01 | |
| 92 | J043140.09+181357.0 | XZTau | 5.90 ± 0.05 | 4.64 ± 0.04 | 2.65 ± 0.02 | 0.53 ± 0.02 | |
| 93 | J043144.47+180831.4 | L1551NE | 9.31 ± 0.02 | 6.88 ± 0.02 | 4.18 ± 0.02 | 0.15 ± 0.02 | |
| 94 | J043150.56+242417.6 | HK Tau AB | 7.81 ± 0.03 | 7.35 ± 0.02 | 5.49 ± 0.02 | 2.46 ± 0.02 | |
| 95 | J043157.79+182136.9 | V710Tau | 7.55 ± 0.02 | 7.14 ± 0.02 | 5.54 ± 0.02 | 3.76 ± 0.03 | |
| 96 | J043159.68+182130.3 | J04315968+1821305 | 8.84 ± 0.02 | 7.98 ± 0.02 | 6.55 ± 0.02 | 4.73 ± 0.03 | |
| 97 | J043215.41+242859.5 | Haro6-13 | 6.63 ± 0.03 | 5.80 ± 0.03 | 3.60 ± 0.02 | 0.89 ± 0.01 | |
| 98 | J043216.06+181246.3 | MHO5 | 9.61 ± 0.03 | 9.03 ± 0.02 | 7.01 ± 0.02 | 5.70 ± 0.05 | |
| 99 | J043222.11+182742.6 | MHO6 | 10.22 ± 0.02 | 9.76 ± 0.02 | 8.45 ± 0.03 | 6.63 ± 0.08 | |
| 100 | J043224.15+225108.2 | 043224.1+225108 | 10.17 ± 0.02 | 9.62 ± 0.02 | 7.60 ± 0.02 | 6.20 ± 0.05 | |
| 101 | J043230.35+173140.6 | GGTauAa | 6.67 ± 0.03 | 6.13 ± 0.02 | 4.08 ± 0.01 | 2.13 ± 0.01 | |
| 102 | J043230.57+241957.3 | FY Tau | 7.31 ± 0.03 | 6.78 ± 0.03 | 5.58 ± 0.02 | 4.03 ± 0.02 | |
| 103 | J043232.06+225726.3 | IRAS 04295+2251 | 8.61 ± 0.02 | 6.84 ± 0.02 | 3.90 ± 0.02 | 1.53 ± 0.02 | |
| 104 | J043241.08+180923.8 | 2MASSJ04324107+1809239 | 9.86 ± 0.03 | 9.36 ± 0.02 | 8.00 ± 0.02 | 6.55 ± 0.08 | Known YSO but not traditional Taurus member |
| 105 | J043243.00+255230.8 | UZ Tau Aab | 6.36 ± 0.04 | 5.72 ± 0.02 | 3.66 ± 0.02 | 1.85 ± 0.02 | |
| 106 | J043249.11+225302.7 | JH112 | 7.41 ± 0.03 | 6.88 ± 0.02 | 4.69 ± 0.02 | 2.68 ± 0.02 | |
| 107 | J043304.22+292149.9 | HD282276 | 7.87 ± 0.02 | 7.71 ± 0.02 | 5.76 ± 0.02 | 2.62 ± 0.02 | Still a candidate YSOb |
| 108 | J043306.21+240933.7 | GH Tau AB | 7.34 ± 0.03 | 6.87 ± 0.02 | 5.28 ± 0.02 | 3.28 ± 0.02 | |
| 109 | J043306.62+240954.9 | V807 Tau AB | 6.51 ± 0.04 | 6.14 ± 0.02 | 5.16 ± 0.02 | 2.97 ± 0.02 | |
| 110 | J043314.36+261423.2 | IRAS 04301+2608 | 11.98 ± 0.02 | 11.13 ± 0.02 | 7.14 ± 0.02 | 3.55 ± 0.02 | |
| 111 | J043316.47+225320.4 | IRAS 04302+2247 | 10.24 ± 0.02 | 9.34 ± 0.02 | 8.83 ± 0.03 | 3.99 ± 0.02 | |
| 112 | J043316.60+262724.3 | None | 13.39 ± 0.03 | 12.33 ± 0.03 | 9.64 ± 0.05 | 7.12 ± 0.10 | Still a candidate YSOb |
| 113 | J043332.80+180043.4 | None | 9.38 ± 0.03 | 8.93 ± 0.02 | 6.46 ± 0.02 | 4.72 ± 0.03 | |
| 114 | J043334.06+242117.0 | GI Tau | 7.10 ± 0.03 | 6.37 ± 0.02 | 4.01 ± 0.02 | 2.54 ± 0.03 | |
| 115 | J043334.55+242105.9 | GK Tau | 6.42 ± 0.04 | 5.80 ± 0.03 | 3.70 ± 0.02 | 1.55 ± 0.02 | |
| 116 | J043336.80+260949.0 | IS Tau AB | 8.06 ± 0.02 | 7.41 ± 0.02 | 5.24 ± 0.02 | 3.74 ± 0.02 | |
| 117 | J043339.06+222720.6 | 043339.0+222720 | 10.16 ± 0.02 | 9.73 ± 0.02 | 8.06 ± 0.03 | 5.04 ± 0.03 | |
| 118 | J043339.07+252038.0 | DL Tau | 6.98 ± 0.03 | 6.24 ± 0.02 | 4.31 ± 0.02 | 2.44 ± 0.02 | |
| 119 | J043339.36+175152.1 | HNTau | 7.26 ± 0.03 | 6.41 ± 0.02 | 4.15 ± 0.02 | 2.18 ± 0.02 | |
| 120 | J043341.73+175039.9 | J04334171+1750402 | 10.07 ± 0.03 | 9.73 ± 0.02 | 8.37 ± 0.03 | 6.42 ± 0.08 | |
| 121 | J043344.66+261500.3 | J04334465+2615005 | 9.19 ± 0.03 | 8.41 ± 0.02 | 6.60 ± 0.02 | 4.78 ± 0.03 | |
| 122 | J043348.73+181009.8 | DMTau | 9.47 ± 0.03 | 9.30 ± 0.02 | 7.04 ± 0.02 | 3.60 ± 0.02 | |
| 123 | J043352.01+225030.0 | CI Tau | 6.78 ± 0.03 | 6.07 ± 0.02 | 4.34 ± 0.02 | 2.47 ± 0.02 | |
| 124 | J043354.69+261327.0 | IT Tau AB | 7.45 ± 0.03 | 6.89 ± 0.02 | 5.22 ± 0.02 | 3.61 ± 0.02 | |
| 125 | J043455.42+242852.9 | AA Tau | 7.43 ± 0.03 | 6.76 ± 0.02 | 4.62 ± 0.02 | 2.54 ± 0.02 | |
| 126 | J043520.21+223214.4 | HO Tau | 8.97 ± 0.02 | 8.50 ± 0.02 | 6.88 ± 0.02 | 5.01 ± 0.03 | |
| 127 | J043527.37+241458.7 | DN Tau | 7.78 ± 0.02 | 7.29 ± 0.02 | 5.12 ± 0.02 | 3.08 ± 0.02 | |
| 128 | J043535.40+240819.9 | IRAS 04325+2402 A | 9.84 ± 0.02 | 8.72 ± 0.02 | 6.36 ± 0.02 | 1.64 ± 0.01 | |
| 129 | J043540.95+241108.4 | CoKu Tau/3 AB | 7.54 ± 0.03 | 6.71 ± 0.02 | 4.78 ± 0.02 | 3.33 ± 0.02 | |
| 130 | J043547.34+225021.6 | HQTau | 6.82 ± 0.03 | 6.11 ± 0.02 | 3.45 ± 0.02 | 1.54 ± 0.01 | |
| 131 | J043552.78+225423.1 | HP Tau AB | 6.54 ± 0.04 | 5.86 ± 0.03 | 3.62 ± 0.02 | 1.47 ± 0.02 | |
| 132 | J043556.83+225435.8 | Haro 6-28 AB | 8.83 ± 0.03 | 8.18 ± 0.02 | 6.31 ± 0.02 | 4.41 ± 0.03 | |
| 133 | J043601.32+172611.9 | 2MASSJ04360131+1726120 | 8.62 ± 0.02 | 8.06 ± 0.02 | 7.16 ± 0.02 | 5.40 ± 0.04 | Known YSO but not traditional Taurus member |
| 134 | J043630.81+184215.3 | HD285893 | 7.16 ± 0.03 | 6.55 ± 0.02 | 3.73 ± 0.02 | 1.46 ± 0.01 | Known YSO but not traditional Taurus member |
| 135 | J043642.05+265339.8 | None | 13.22 ± 0.03 | 11.49 ± 0.02 | 9.07 ± 0.03 | 6.47 ± 0.07 | Still a candidate YSOb |
| 136 | J043756.70+254623.0 | ITG 1 | 12.11 ± 0.03 | 11.29 ± 0.02 | 8.89 ± 0.03 | 7.07 ± 0.10 | |
| 137 | J043814.87+261139.8 | J04381486+2611399 | 11.10 ± 0.02 | 10.06 ± 0.02 | 7.87 ± 0.02 | 5.06 ± 0.03 | |
| 138 | J043821.33+260913.6 | GM Tau | 9.52 ± 0.02 | 8.83 ± 0.02 | 7.07 ± 0.02 | 5.34 ± 0.04 | |
| 139 | J043828.58+261049.4 | DO Tau | 6.31 ± 0.04 | 5.42 ± 0.03 | 3.43 ± 0.02 | 1.20 ± 0.01 | |
| 140 | J043835.31+261038.8 | HV Tau AB | 7.77 ± 0.02 | 7.51 ± 0.02 | 6.71 ± 0.02 | 3.62 ± 0.03 | |
| 141 | J043858.60+233635.0 | J0438586+2336352 | 10.72 ± 0.03 | 10.19 ± 0.02 | 8.32 ± 0.03 | 6.55 ± 0.07 | |
| 142 | J043901.63+233602.7 | J0439016+2336030 | 9.87 ± 0.02 | 9.46 ± 0.02 | 7.95 ± 0.02 | 6.39 ± 0.06 | |
| 143 | J043903.95+254426.2 | CFHT-6 | 10.98 ± 0.02 | 10.38 ± 0.02 | 8.33 ± 0.03 | 6.56 ± 0.07 | (SDSS spectrum: STAR -M9) |
| 144 | J043905.24+233744.9 | J04390525+2337450 | 10.63 ± 0.02 | 10.02 ± 0.02 | 7.28 ± 0.02 | 3.69 ± 0.03 | |
| 145 | J043913.89+255320.9 | IRAS 04361+2547 AB | 8.68 ± 0.02 | 7.08 ± 0.02 | 2.76 ± 0.02 | -1.01 ± 0.01 | |
| 146 | J043917.42+224753.3 | VYTau | 8.49 ± 0.02 | 8.03 ± 0.02 | 6.19 ± 0.02 | 4.76 ± 0.03 | |
| 147 | J043917.79+222103.3 | LkCa 15 | 7.49 ± 0.03 | 7.15 ± 0.02 | 5.67 ± 0.02 | 3.60 ± 0.03 | |
| 148 | J043920.91+254501.9 | GN Tau B | 7.13 ± 0.03 | 6.51 ± 0.02 | 4.88 ± 0.02 | 3.08 ± 0.02 | |
| 149 | J043933.64+235921.0 | J04393364+2359212 | 9.78 ± 0.02 | 9.15 ± 0.02 | 6.97 ± 0.02 | 5.26 ± 0.03 | |
| 150 | J043935.18+254144.4 | IRAS 04365+2535 | 7.96 ± 0.02 | 5.61 ± 0.03 | 3.42 ± 0.02 | 0.17 ± 0.01 | |
| 151 | J043944.87+260152.6 | ITG 15 | 8.41 ± 0.02 | 7.78 ± 0.02 | 6.26 ± 0.02 | 4.09 ± 0.03 | |
| 152 | J043947.47+260140.6 | CFHT-4 | 9.83 ± 0.03 | 8.97 ± 0.02 | 6.99 ± 0.02 | 5.17 ± 0.04 | (SDSS spectrum: STAR -M9) |
| 153 | J043953.96+260309.7 | IRAS 04368+2557 | 13.03 ± 0.05 | 9.75 ± 0.03 | 8.74 ± 0.04 | 3.12 ± 0.02 | |
| 154 | J044000.67+235820.9 | J04400067+2358211 | 11.15 ± 0.04 | 10.66 ± 0.03 | 8.91 ± 0.03 | 6.63 ± 0.07 | |
| 155 | J044007.99+260525.3 | IRAS 04370+2559 | 8.21 ± 0.02 | 7.27 ± 0.02 | 4.85 ± 0.02 | 2.74 ± 0.02 | |
| 156 | J044049.50+255119.1 | JH223 | 8.90 ± 0.02 | 8.43 ± 0.02 | 7.07 ± 0.02 | 5.30 ± 0.04 | |
| 157 | J044108.26+255607.3 | ITG 33 A | 9.76 ± 0.02 | 8.87 ± 0.02 | 6.63 ± 0.02 | 4.50 ± 0.03 | |
| 158 | J044110.78+255511.5 | ITG 34 | 11.03 ± 0.03 | 10.31 ± 0.02 | 8.31 ± 0.04 | 6.71 ± 0.10 | |
| 159 | J044112.68+254635.0 | IRAS 04381+2540 | 9.85 ± 0.02 | 7.67 ± 0.02 | 4.85 ± 0.02 | 1.71 ± 0.02 | |
| 160 | J044116.81+283959.8 | CoKuTau4 | 8.50 ± 0.03 | 8.35 ± 0.02 | 6.66 ± 0.02 | 2.47 ± 0.02 | |
| 161 | J044124.65+254352.7 | ITG 40 | 10.78 ± 0.02 | 9.75 ± 0.02 | 8.29 ± 0.03 | 5.63 ± 0.04 | |
| 162 | J044125.75+254349.3 | IRA04412575+2543492 | 14.48 ± 0.04 | 12.33 ± 0.03 | 9.35 ± 0.04 | 7.05 ± 0.10 | Still a candidate YSOb |
| 163 | J044138.82+255626.7 | IRAS 04385+2550 | 8.16 ± 0.02 | 7.36 ± 0.02 | 4.55 ± 0.01 | 2.05 ± 0.01 | |
| 164 | J044148.24+253430.4 | J04414825+2534304 | 11.60 ± 0.03 | 10.78 ± 0.02 | 8.53 ± 0.03 | 6.29 ± 0.06 | (SDSS spectrum: STAR -M9) |
| 165 | J044207.77+252311.5 | V955 Tau Ab | 6.96 ± 0.03 | 6.31 ± 0.02 | 4.49 ± 0.02 | 2.76 ± 0.02 | |
| 166 | J044221.02+252034.2 | CIDA-7 | 9.68 ± 0.03 | 9.03 ± 0.02 | 6.83 ± 0.02 | 4.38 ± 0.02 | |
| 167 | J044237.68+251537.2 | DP Tau | 7.32 ± 0.03 | 6.49 ± 0.02 | 4.23 ± 0.02 | 2.01 ± 0.02 | |
| 168 | J044303.08+252018.6 | GO Tau | 9.02 ± 0.02 | 8.57 ± 0.02 | 6.58 ± 0.02 | 4.43 ± 0.03 | |
| 169 | J044315.85+235358.2 | None | 13.15 ± 0.03 | 11.73 ± 0.03 | 9.12 ± 0.03 | 6.66 ± 0.06 | Still a candidate YSOb |
| 170 | J044320.22+294005.8 | CIDA-14 | 9.11 ± 0.02 | 8.65 ± 0.02 | 6.86 ± 0.02 | 5.64 ± 0.04 | |
| 171 | J044427.14+251216.2 | IRAS 04414+2506 | 10.06 ± 0.03 | 9.36 ± 0.02 | 6.73 ± 0.02 | 4.34 ± 0.03 | |
| 172 | J044653.05+170000.1 | DQTau | 7.07 ± 0.03 | 6.45 ± 0.02 | 4.31 ± 0.02 | 2.28 ± 0.02 | |
| 173 | J044659.01+170238.4 | Haro6-37 | 6.35 ± 0.04 | 5.69 ± 0.03 | 4.11 ± 0.02 | 2.45 ± 0.02 | |
| 174 | J044748.59+292511.0 | DSTau | 7.39 ± 0.03 | 6.84 ± 0.02 | 5.18 ± 0.02 | 3.68 ± 0.02 | |
| 175 | J044832.35+234746.9 | None | 13.01 ± 0.03 | 11.72 ± 0.02 | 8.69 ± 0.03 | 6.32 ± 0.05 | Still a candidate YSOb |
| 176 | J045147.36+304713.1 | UYAur | 6.13 ± 0.04 | 4.92 ± 0.03 | 2.46 ± 0.02 | 0.38 ± 0.01 | |
| 177 | J045206.67+304717.2 | IRAS 04489+3042 | 8.84 ± 0.03 | 7.56 ± 0.02 | 5.09 ± 0.02 | 2.52 ± 0.02 | |
| 178 | J045209.70+303745.2 | Haro6-39 | 9.95 ± 0.02 | 8.88 ± 0.02 | 6.18 ± 0.02 | 3.55 ± 0.02 | |
| 179 | J045423.67+170953.3 | St34 | 9.59 ± 0.02 | 9.40 ± 0.02 | 7.67 ± 0.02 | 5.42 ± 0.04 | |
| 180 | J045510.97+302159.2 | GMAur | 8.38 ± 0.02 | 8.23 ± 0.02 | 6.06 ± 0.02 | 2.52 ± 0.02 | |
| 181 | J045545.34+301938.6 | 2MJ04554535+3019389 | 10.16 ± 0.02 | 9.65 ± 0.02 | 8.10 ± 0.03 | 6.51 ± 0.11 | |
| 182 | J045556.06+303620.7 | J04555605+3036209 | 8.93 ± 0.02 | 8.43 ± 0.02 | 6.04 ± 0.02 | 3.79 ± 0.03 | |
| 183 | J045559.39+303401.4 | SUAur | 5.07 ± 0.05 | 4.12 ± 0.04 | 2.54 ± 0.02 | -0.09 ± 0.01 | |
| 184 | J045601.18+302634.5 | J04560118+3026348 | 9.49 ± 0.02 | 9.00 ± 0.02 | 7.21 ± 0.02 | 5.91 ± 0.05 | |
| 185 | J045846.27+295036.9 | None | 4.90 ± 0.06 | 3.60 ± 0.04 | 1.54 ± 0.01 | 0.09 ± 0.01 | |
| 186 | J045851.41+283123.8 | BSTau | 8.60 ± 0.02 | 8.08 ± 0.02 | 6.03 ± 0.02 | 3.93 ± 0.03 | Known YSO but not traditional Taurus member |
| 187 | J045903.04+300300.1 | HBHA3214-06 | 8.91 ± 0.03 | 8.57 ± 0.02 | 7.13 ± 0.02 | 5.14 ± 0.03 | Known YSO but not traditional Taurus member |
| 188 | J050003.10+300107.4 | GZAur | 7.70 ± 0.02 | 7.00 ± 0.02 | 5.14 ± 0.02 | 3.36 ± 0.02 | Known YSO but not traditional Taurus member |
| 189 | J050306.59+252319.5 | V836Tau | 8.14 ± 0.03 | 7.65 ± 0.02 | 5.89 ± 0.02 | 3.89 ± 0.02 | |
| 190 | J050441.39+250954.4 | CIDA-8 | 9.28 ± 0.02 | 8.84 ± 0.02 | 7.25 ± 0.02 | 5.20 ± 0.03 | |
| 191 | J050509.00+252208.0 | IRAS 05020+2518 | 5.29 ± 0.06 | 5.11 ± 0.03 | 3.65 ± 0.02 | 2.52 ± 0.02 | Known YSO but not traditional Taurus member |
| 192 | J050522.82+253130.8 | CIDA-9 | 9.20 ± 0.03 | 8.31 ± 0.02 | 6.01 ± 0.02 | 4.18 ± 0.03 | |
| 193 | J050623.33+243219.8 | CIDA-11 | 9.21 ± 0.02 | 8.81 ± 0.02 | 7.13 ± 0.02 | 5.67 ± 0.04 | |
| 194 | J050746.97+312018.4 | HOAur | 7.59 ± 0.02 | 7.22 ± 0.02 | 5.99 ± 0.02 | 4.11 ± 0.02 | Known YSO but not traditional Taurus member |
| 195 | J050749.55+302404.9 | RWAur | 6.20 ± 0.04 | 5.21 ± 0.03 | 3.35 ± 0.02 | 1.48 ± 0.02 | |
| 196 | J050754.96+250015.4 | CIDA-12 | 10.16 ± 0.02 | 9.79 ± 0.02 | 7.85 ± 0.02 | 5.98 ± 0.05 |
Notes. aSee the full table description in Section 3.3. bObject identified in Rebull et al. (2010) as a candidate Taurus member, but discussed there as needing additional data to confirm/refute it as a Taurus member.
A machine-readable version of the table is available.
Note that this table is not meant to be a complete list of Taurus members detected with WISE, but instead a list of all objects in the direction of Taurus, identified as young, detected in WISE with S/N > 7 in all four bands and identified using the Koenig et al. (2011) method as having an IR excess. Some bona fide members of Taurus are either too faint or do not have enough color excess to be identified in this manner.
3.4. Manual Inspection
For the remaining 818 WISE-identified IR excess objects that have not been associated previously with young stars, we conducted a preliminary sorting into "likely contaminant" or "perhaps YSO" bins. The categorization was based on matches to objects in SIMBAD (and literature therein), matches to objects we identified as contaminants in Rebull et al. (2010), matches to the 2MASS Extended Source Catalog, and identification as extended in the SDSS pipeline. We then generated SEDs using all photometric data in our database for these objects and inspected each of them. Based on our experience, we then categorized each of the objects as still possible YSO candidates, or likely extragalactic objects. This classification is easier when there are more photometric bands; objects for which there are SDSS, 2MASS, and WISE photometry are more likely appropriately classified during this process than those without optical photometry or with just WISE photometry. Therefore, this process may have dropped viable YSO candidates similar to, e.g., MHO-1 or Haro 6-39, which have very flat SEDs (and moreover MHO-1 has just WISE photometry). Statistically the objects we have dropped on this basis are very likely to be extragalactic. Because this process is not perfect, the objects dropped as a result of SED shape are identified in the "notes" column of the tables below specifically so that follow-up optical photometry (for example) can be obtained.
After this process, there were ∼130 objects which we could not yet reject as YSO candidates. For these objects, we inspected the images in all four WISE bands, and, if necessary, 2MASS, POSS, and if possible, SDSS. We then identified objects as likely subject to source contamination, resolved as a likely galaxy, or still apparently clean, relatively isolated point sources.
We have thus identified 686 objects that are confirmed or likely galaxies, 13 foreground or background stars, 1 PN, and 24 objects that seem to be subject to confusion in the relatively large WISE beam (and therefore any excess seen in the SED is likely to be contaminated by the confused source). There are 94 objects still surviving in the potential YSO candidate list. The rejected objects appear in Table 2, and the 94 surviving objects appear in Table 3. SEDs for the 94 potential YSO objects appear in the Appendix.
Table 2. Multiband Measurements of WISE-identified Rejected YSO Candidates in Taurus Region
| Line | Catalog Number | Name | W1 (3.4 μm) | W2 (4.6 μm) | W3 (12 μm) | W4 (22 μm) | Notes |
|---|---|---|---|---|---|---|---|
| Num. | (mag) | (mag) | (mag) | (mag) | |||
| 1 | J035135.81+260914.3 | 2MASX03513585+2609139 | 13.82 ± 0.03 | 12.94 ± 0.03 | 9.67 ± 0.05 | 7.47 ± 0.13 | Galaxy: extended in 2MASS, SED shape |
| 2 | J035228.38+252002.4 | None | 12.14 ± 0.03 | 10.94 ± 0.02 | 8.36 ± 0.03 | 6.34 ± 0.06 | Galaxy: SED shape |
| 3 | J035234.58+252729.5 | None | 13.37 ± 0.03 | 12.28 ± 0.02 | 9.19 ± 0.04 | 6.54 ± 0.07 | Galaxy: SED shape |
| 4 | J035300.20+274013.1 | None | 13.89 ± 0.03 | 12.88 ± 0.03 | 9.99 ± 0.06 | 7.81 ± 0.16 | Galaxy: SED shape |
| 5 | J035300.52+290542.9 | None | 12.05 ± 0.02 | 11.78 ± 0.03 | 8.40 ± 0.03 | 7.03 ± 0.08 | Galaxy: SED shape |
| 6 | J035309.58+272953.5 | 2MASX03530961+2729541 | 12.27 ± 0.03 | 11.11 ± 0.02 | 8.36 ± 0.03 | 6.23 ± 0.05 | Galaxy: extended in 2MASS, SED shape |
| 7 | J035322.85+281358.1 | None | 14.77 ± 0.04 | 13.13 ± 0.03 | 9.69 ± 0.05 | 6.96 ± 0.08 | Galaxy: SED shape |
| 8 | J035334.67+270854.1 | None | 12.78 ± 0.03 | 11.67 ± 0.02 | 9.02 ± 0.03 | 6.63 ± 0.06 | Galaxy: SED shape |
| 9 | J035334.93+253651.3 | None | 11.92 ± 0.03 | 10.95 ± 0.02 | 8.18 ± 0.03 | 6.02 ± 0.04 | Galaxy: SED shape |
| 10 | J035348.05+291411.3 | None | 13.52 ± 0.03 | 12.38 ± 0.03 | 9.61 ± 0.04 | 7.24 ± 0.10 | Galaxy: SED shape |
Only a portion of this table is shown here to demonstrate its form and content. A machine-readable version of the full table is available.
Download table as: DataTypeset image
Table 3. Multiband Measurements of WISE-identified New YSO Candidates in Taurus Region
| Line | Catalog Number | Name | W1 (3.4 μm) | W2 (4.6 μm) | W3 (12 μm) | W4 (22 μm) | Notes |
|---|---|---|---|---|---|---|---|
| Num. | (mag) | (mag) | (mag) | (mag) | |||
| 1 | J035323.82+271838.3 | None | 11.29 ± 0.03 | 10.58 ± 0.02 | 8.66 ± 0.03 | 6.75 ± 0.08 | Within Pleiades tidal radius (Section 4.1) |
| 2 | J035412.25+312034.0 | None | 12.10 ± 0.03 | 11.76 ± 0.02 | 9.69 ± 0.05 | 7.64 ± 0.14 | |
| 3 | J035454.27+295944.0 | None | 8.04 ± 0.02 | 7.34 ± 0.02 | 5.31 ± 0.02 | 4.05 ± 0.02 | |
| 4 | J035519.09+233501.8 | None | 13.60 ± 0.03 | 12.79 ± 0.03 | 9.55 ± 0.05 | 6.76 ± 0.07 | Within Pleiades tidal radius (Section 4.1) |
| 5 | J035535.05+291319.3 | None | 13.86 ± 0.03 | 13.06 ± 0.03 | 10.19 ± 0.06 | 7.43 ± 0.13 | Within Pleiades tidal radius (Section 4.1) |
| 6 | J035919.63+310730.1 | None | 13.56 ± 0.03 | 12.39 ± 0.03 | 9.08 ± 0.03 | 6.90 ± 0.08 | |
| 7 | J035935.02+315409.6 | 2MASX03593501+3154090 | 13.55 ± 0.03 | 13.12 ± 0.03 | 8.40 ± 0.03 | 4.91 ± 0.03 | |
| 8 | J035958.81+312901.1 | HD281395 | 8.95 ± 0.02 | 8.95 ± 0.02 | 8.69 ± 0.03 | 6.25 ± 0.05 | Excess just at 22 (Section 4.6) |
| 9 | J040056.13+314301.3 | None | 7.63 ± 0.03 | 7.14 ± 0.02 | 5.30 ± 0.02 | 2.05 ± 0.02 | |
| 10 | J040159.15+321941.2 | HD281479 | 9.09 ± 0.02 | 9.09 ± 0.02 | 8.24 ± 0.02 | 6.20 ± 0.05 | Excess just at 22 (Section 4.6) |
| 11 | J040204.41+251210.3 | None | 13.78 ± 0.03 | 13.04 ± 0.03 | 10.20 ± 0.07 | 7.54 ± 0.13 | Within Pleiades tidal radius (Section 4.1). Good JHK (Section 4.4) |
| 12 | J040226.63+314409.0 | None | 11.98 ± 0.02 | 11.46 ± 0.02 | 9.45 ± 0.04 | 7.21 ± 0.09 | |
| 13 | J040259.96+315703.9 | None | 9.59 ± 0.03 | 9.33 ± 0.02 | 8.44 ± 0.03 | 5.26 ± 0.03 | |
| 14 | J040403.90+320116.8 | None | 13.16 ± 0.03 | 12.63 ± 0.03 | 10.18 ± 0.07 | 7.43 ± 0.14 | |
| 15 | J040407.21+315914.5 | None | 12.23 ± 0.03 | 11.99 ± 0.02 | 10.13 ± 0.06 | 7.54 ± 0.14 | |
| 16 | J040559.61+295638.2 | None | 7.73 ± 0.03 | 7.16 ± 0.02 | 5.22 ± 0.02 | 1.93 ± 0.02 | |
| 17 | J040612.75+264308.0 | None | 14.31 ± 0.03 | 13.10 ± 0.03 | 9.39 ± 0.04 | 6.66 ± 0.07 | Within Pleiades tidal radius (Section 4.1) |
| 18 | J040636.44+251019.1 | None | 14.48 ± 0.04 | 13.12 ± 0.03 | 9.34 ± 0.04 | 6.34 ± 0.06 | Within Pleiades tidal radius (Section 4.1) |
| 19 | J040644.43+254018.1 | None | 11.42 ± 0.03 | 11.03 ± 0.02 | 9.25 ± 0.04 | 7.49 ± 0.14 | Within Pleiades tidal radius (Section 4.1) |
| 20 | J040651.36+254128.3 | V1195Tau | 7.53 ± 0.03 | 7.33 ± 0.02 | 6.07 ± 0.02 | 4.56 ± 0.02 | Within Pleiades tidal radius (Section 4.1). Excess just at 22 (Section 4.6) |
| 21 | J040716.73+240257.6 | None | 12.96 ± 0.03 | 11.77 ± 0.02 | 9.18 ± 0.04 | 6.91 ± 0.09 | Within Pleiades tidal radius (Section 4.1) |
| 22 | J040805.16+300627.6 | None | 13.51 ± 0.03 | 12.42 ± 0.03 | 9.69 ± 0.05 | 7.34 ± 0.12 | Good JHK (Section 4.4) |
| 23 | J040809.49+222434.8 | None | 13.63 ± 0.03 | 12.11 ± 0.03 | 9.23 ± 0.04 | 7.24 ± 0.12 | Within Pleiades tidal radius (Section 4.1) |
| 24 | J040913.79+313632.5 | None | 12.15 ± 0.02 | 11.74 ± 0.02 | 10.02 ± 0.06 | 7.54 ± 0.14 | |
| 25 | J041025.61+315150.7 | HD281664 | 9.88 ± 0.03 | 9.86 ± 0.03 | 9.29 ± 0.04 | 7.11 ± 0.09 | Excess just at 22 (Section 4.6) |
| 26 | J041130.69+295628.3 | None | 12.93 ± 0.03 | 11.46 ± 0.02 | 8.47 ± 0.03 | 6.05 ± 0.05 | |
| 27 | J041141.34+261341.3 | None | 13.61 ± 0.03 | 12.36 ± 0.03 | 9.69 ± 0.05 | 7.34 ± 0.12 | Within Pleiades tidal radius (Section 4.1). Iffy r, z (Section 4.5) |
| 28 | J041240.69+243815.6 | None | 9.64 ± 0.02 | 9.24 ± 0.02 | 6.87 ± 0.02 | 4.59 ± 0.03 | Within Pleiades tidal radius (Section 4.1). Good r, z (Section 4.5) |
| 29 | J041320.01+311047.1 | HD281789 | 6.93 ± 0.03 | 6.38 ± 0.02 | 2.99 ± 0.02 | 0.61 ± 0.02 | |
| 30 | J041419.20+220138.0 | None | 13.15 ± 0.03 | 12.22 ± 0.03 | 9.14 ± 0.04 | 6.72 ± 0.07 | Good JHK (Section 4.4) |
| 31 | J041551.98+315514.0 | None | 12.93 ± 0.03 | 12.55 ± 0.03 | 10.28 ± 0.08 | 7.24 ± 0.10 | (SDSS spectrum: STAR -M5) good r, z (Section 4.5) |
| 32 | J041734.21+360814.8 | None | 12.31 ± 0.03 | 11.97 ± 0.03 | 8.45 ± 0.03 | 5.55 ± 0.04 | |
| 33 | J041752.27+360720.2 | None | 11.46 ± 0.03 | 11.45 ± 0.03 | 9.83 ± 0.05 | 7.67 ± 0.15 | Excess just at 22 (Section 4.6) |
| 34 | J041831.61+352732.7 | None | 11.82 ± 0.02 | 9.47 ± 0.02 | 6.72 ± 0.02 | 3.79 ± 0.02 | Iffy r, z (Section 4.5) |
| 35 | J041946.18+194539.8 | HD284346 | 8.70 ± 0.02 | 8.72 ± 0.02 | 8.49 ± 0.03 | 5.84 ± 0.04 | Excess just at 22 (Section 4.6) |
| 36 | J042118.39+364820.5 | None | 14.13 ± 0.04 | 12.65 ± 0.03 | 8.86 ± 0.03 | 6.24 ± 0.06 | |
| 37 | J042146.44+240147.1 | None | 14.52 ± 0.04 | 13.16 ± 0.04 | 9.68 ± 0.05 | 6.92 ± 0.09 | |
| 38 | J042213.75+152529.9 | None | 6.94 ± 0.03 | 6.39 ± 0.02 | 4.99 ± 0.02 | 1.93 ± 0.01 | AV > 2 (Section 4.2) |
| 39 | J042220.80+170812.0 | None | 14.05 ± 0.03 | 12.61 ± 0.03 | 9.13 ± 0.03 | 7.06 ± 0.09 | Iffy r, z (Section 4.5) |
| 40 | J042224.69+333459.3 | None | 11.43 ± 0.02 | 11.45 ± 0.02 | 8.84 ± 0.03 | 7.16 ± 0.10 | |
| 41 | J042350.39+164035.1 | None | 14.37 ± 0.04 | 13.04 ± 0.04 | 9.46 ± 0.04 | 6.88 ± 0.08 | |
| 42 | J042541.31+353718.8 | None | 8.87 ± 0.03 | 8.38 ± 0.02 | 7.27 ± 0.02 | 3.81 ± 0.03 | |
| 43 | J042604.39+342435.7 | None | 10.77 ± 0.02 | 10.35 ± 0.02 | 8.92 ± 0.03 | 6.49 ± 0.06 | |
| 44 | J042623.36+213508.1 | None | 13.77 ± 0.03 | 13.02 ± 0.05 | 10.03 ± 0.09 | 6.65 ± 0.11 | |
| 45 | J042625.87+351507.6 | None | 10.44 ± 0.03 | 9.56 ± 0.02 | 7.36 ± 0.02 | 5.53 ± 0.04 | Good r, z (Section 4.5) |
| 46 | J042659.19+183548.7 | None | 12.98 ± 0.03 | 11.81 ± 0.02 | 8.57 ± 0.03 | 5.77 ± 0.04 | Iffy r, z (Section 4.5) |
| 47 | J042818.51+303605.3 | None | 14.40 ± 0.04 | 13.62 ± 0.05 | 9.20 ± 0.04 | 7.10 ± 0.10 | |
| 48 | J042850.54+184436.1 | None | 9.79 ± 0.03 | 9.42 ± 0.03 | 7.19 ± 0.02 | 5.09 ± 0.04 | AV > 2 (Section 4.2) |
| 49 | J042923.42+245314.8 | None | 11.94 ± 0.03 | 11.68 ± 0.03 | 9.22 ± 0.04 | 6.97 ± 0.08 | |
| 50 | J042954.77+291228.5 | None | 10.61 ± 0.02 | 10.56 ± 0.02 | 9.66 ± 0.05 | 6.74 ± 0.08 | Excess just at 22 (Section 4.6) |
| 51 | J043118.56+324237.8 | None | 13.81 ± 0.03 | 13.03 ± 0.04 | 9.92 ± 0.06 | 7.43 ± 0.13 | |
| 52 | J043131.61+293819.0 | None | 13.73 ± 0.03 | 12.96 ± 0.03 | 9.96 ± 0.06 | 7.17 ± 0.09 | |
| 53 | J043229.33+281434.9 | None | 13.91 ± 0.03 | 13.01 ± 0.04 | 9.50 ± 0.04 | 6.74 ± 0.08 | |
| 54 | J043326.74+204758.7 | None | 12.76 ± 0.03 | 11.56 ± 0.03 | 9.06 ± 0.04 | 6.91 ± 0.08 | Iffy r, z (Section 4.5) |
| 55 | J043327.90+175843.8 | None | 10.05 ± 0.02 | 8.88 ± 0.02 | 6.53 ± 0.02 | 4.07 ± 0.03 | Good JHK (Section 4.4) |
| 56 | J043616.13+322119.4 | None | 11.64 ± 0.02 | 11.51 ± 0.02 | 9.71 ± 0.05 | 6.15 ± 0.05 | |
| 57 | J043714.47+323011.7 | None | 14.28 ± 0.04 | 13.63 ± 0.05 | 9.10 ± 0.03 | 6.05 ± 0.05 | |
| 58 | J043720.50+203024.4 | None | 11.69 ± 0.03 | 11.64 ± 0.02 | 9.45 ± 0.04 | 6.95 ± 0.08 | |
| 59 | J043741.83+282112.6 | None | 14.26 ± 0.03 | 13.20 ± 0.03 | 9.37 ± 0.04 | 6.54 ± 0.06 | |
| 60 | J043837.06+183934.2 | None | 14.05 ± 0.03 | 12.91 ± 0.03 | 9.73 ± 0.05 | 6.53 ± 0.06 | |
| 61 | J043845.02+173743.1 | None | 10.30 ± 0.02 | 9.88 ± 0.02 | 8.07 ± 0.02 | 6.02 ± 0.05 | |
| 62 | J043847.26+173725.9 | None | 11.39 ± 0.02 | 10.90 ± 0.02 | 9.04 ± 0.03 | 7.05 ± 0.09 | |
| 63 | J044118.60+311544.2 | None | 12.27 ± 0.03 | 11.41 ± 0.03 | 8.55 ± 0.03 | 6.75 ± 0.08 | |
| 64 | J044257.69+312822.6 | None | 12.67 ± 0.03 | 11.39 ± 0.02 | 8.18 ± 0.02 | 5.98 ± 0.05 | |
| 65 | J044305.62+291737.6 | None | 13.66 ± 0.03 | 13.18 ± 0.03 | 10.98 ± 0.12 | 7.38 ± 0.12 | |
| 66 | J044428.98+201537.5 | None | 13.16 ± 0.03 | 12.62 ± 0.03 | 7.96 ± 0.02 | 4.89 ± 0.03 | Iffy r, z (Section 4.5) |
| 67 | J044512.68+194501.1 | None | 13.54 ± 0.03 | 12.51 ± 0.03 | 9.30 ± 0.04 | 6.94 ± 0.08 | Good JHK (Section 4.4) |
| 68 | J044717.49+193149.1 | None | 14.11 ± 0.03 | 12.99 ± 0.03 | 9.65 ± 0.05 | 6.80 ± 0.07 | |
| 69 | J044719.33+325449.8 | None | 13.58 ± 0.03 | 12.35 ± 0.03 | 9.33 ± 0.04 | 6.72 ± 0.07 | Good JHK (Section 4.4) |
| 70 | J044746.77+305635.8 | 2MASX04474674+3056355 | 11.53 ± 0.03 | 11.06 ± 0.03 | 9.22 ± 0.04 | 7.06 ± 0.10 | |
| 71 | J044801.88+294902.1 | 2MASX04480189+2949023 | 13.49 ± 0.03 | 12.69 ± 0.03 | 9.62 ± 0.05 | 7.13 ± 0.10 | Good JHK (Section 4.4) |
| 72 | J044813.48+292453.5 | None | 8.44 ± 0.02 | 7.74 ± 0.02 | 5.33 ± 0.02 | 3.53 ± 0.02 | Good JHK (Section 4.4) |
| 73 | J044837.31+304145.1 | None | 12.29 ± 0.03 | 12.28 ± 0.03 | 10.07 ± 0.06 | 7.16 ± 0.09 | |
| 74 | J045122.95+300206.8 | None | 11.98 ± 0.02 | 11.78 ± 0.02 | 9.03 ± 0.03 | 6.91 ± 0.09 | |
| 75 | J045141.49+305519.5 | 2MASX04514147+3055196 | 12.36 ± 0.02 | 11.73 ± 0.02 | 7.90 ± 0.02 | 5.20 ± 0.04 | AV>2 (Section 4.2) |
| 76 | J045141.56+292918.9 | None | 14.58 ± 0.04 | 13.23 ± 0.04 | 9.60 ± 0.05 | 6.82 ± 0.08 | |
| 77 | J045352.77+222813.7 | None | 12.07 ± 0.03 | 10.97 ± 0.02 | 8.07 ± 0.03 | 5.67 ± 0.04 | Good JHK (Section 4.4) |
| 78 | J045400.09+254219.2 | None | 13.96 ± 0.03 | 13.22 ± 0.03 | 9.94 ± 0.06 | 7.04 ± 0.09 | |
| 79 | J045522.17+250923.2 | None | 13.43 ± 0.03 | 12.25 ± 0.03 | 9.02 ± 0.03 | 6.45 ± 0.06 | Iffy r, z (Section 4.5) |
| 80 | J045737.44+232513.9 | None | 10.99 ± 0.02 | 10.98 ± 0.02 | 8.71 ± 0.03 | 5.89 ± 0.04 | |
| 81 | J045808.02+251852.6 | None | 10.54 ± 0.02 | 10.59 ± 0.02 | 9.88 ± 0.06 | 7.40 ± 0.12 | Good r, z (Section 4.5). Excess just at 22 (Section 4.6) |
| 82 | J045913.28+320201.3 | None | 11.99 ± 0.02 | 10.83 ± 0.02 | 8.03 ± 0.02 | 5.47 ± 0.04 | Good JHK (Section 4.4) |
| 83 | J045943.63+252647.2 | None | 14.58 ± 0.04 | 12.99 ± 0.03 | 9.36 ± 0.04 | 6.93 ± 0.09 | Iffy r, z (Section 4.5) |
| 84 | J050213.63+301014.2 | None | 13.63 ± 0.03 | 12.38 ± 0.03 | 9.47 ± 0.04 | 7.19 ± 0.10 | |
| 85 | J050234.82+274549.6 | None | 10.77 ± 0.02 | 10.36 ± 0.02 | 7.57 ± 0.02 | 5.37 ± 0.04 | |
| 86 | J050239.85+245933.5 | None | 10.31 ± 0.03 | 9.76 ± 0.02 | 7.38 ± 0.02 | 6.13 ± 0.05 | |
| 87 | J050357.98+265828.8 | HD284075 | 9.27 ± 0.02 | 9.27 ± 0.02 | 8.87 ± 0.03 | 6.09 ± 0.05 | Excess just at 22 (Section 4.6) |
| 88 | J050450.13+264314.6 | HD32509 | 6.92 ± 0.03 | 6.94 ± 0.02 | 5.81 ± 0.02 | 3.35 ± 0.02 | Excess just at 22 (Section 4.6) |
| 89 | J050547.69+243058.9 | None | 11.66 ± 0.03 | 11.53 ± 0.02 | 8.74 ± 0.03 | 7.35 ± 0.11 | |
| 90 | J050726.91+211716.5 | None | 13.36 ± 0.03 | 12.60 ± 0.03 | 9.43 ± 0.04 | 6.98 ± 0.09 | |
| 91 | J050731.86+205428.2 | None | 12.06 ± 0.02 | 12.07 ± 0.02 | 10.32 ± 0.07 | 7.74 ± 0.15 | |
| 92 | J050739.03+231106.5 | None | 11.00 ± 0.03 | 10.64 ± 0.02 | 9.16 ± 0.04 | 7.48 ± 0.13 | |
| 93 | J050836.48+270614.7 | None | 11.89 ± 0.03 | 11.41 ± 0.02 | 9.16 ± 0.04 | 7.31 ± 0.12 | |
| 94 | J050841.75+311521.9 | None | 11.08 ± 0.02 | 10.59 ± 0.02 | 9.00 ± 0.03 | 7.41 ± 0.12 |
A machine-readable version of the table is available.
4. OVERALL PROPERTIES
We now attempt to assess the overall contamination as well as identify very high-likelihood YSOs out of our candidate list using the ancillary data we have amassed.
4.1. Projected Location
Figure 3 shows the location on the sky of the recovered previously identified YSOs, the rejected objects, and the surviving candidate YSOs. The previously identified YSOs are generally highly clustered along the filamentary distribution of gas and dust, and the new objects are less clustered. This is as expected, since many searches have focused on the regions already known to contain young stars, and our goal was to look for new YSOs outside the canonical groupings of previously known Taurus members. However, this could also be an indication of persistent contamination in the surviving list of YSO candidates.
Figure 3. Location on the sky of the recovered previously identified YSOs (+), the rejected objects (×), and the best remaining candidates (circles). The previously identified YSOs are generally highly clustered, and the newly identified candidates are less clustered.
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Standard image High-resolution imageFigure 4 is a more quantitative view of the clustering seen in Figure 3, showing a distribution of separations. Previously identified YSOs are very close, on average, to another previously identified YSO. The contaminants have a much broader distribution and are further from the known YSOs on average. The distribution of candidate YSOs is closer to that of the contaminants than the previously identified YSOs.
Figure 4. Histogram (top two; middle is zoomed-in version of the top) and cumulative distribution (bottom; fraction of sample with number of points less than the corresponding x value) of distances in arcminutes to the nearest previously identified YSO for recovered known YSOs (green, solid line; distance is to the nearest other YSO), rejected contaminants (red, dotted line), and new YSO candidates (black, dashed line).
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Standard image High-resolution imageIn the context of proximity of objects to other known objects, as noted above, some of our objects can be found within the tidal radius of the Pleiades (∼6°; Adams et al. 2001). Objects identified here that are within ∼6°of the Pleiades could belong to the Pleiades rather than Taurus. One recovered known YSO is within this radius (IRAS 04016+26102), 104 rejected contaminants, and 12 YSO candidates (J035323.82+271838.3, J035519.09+233501.8, J035535.05+291319.3, J040204.41+251210.3, J040612.75+264308.0, J040636.44+251019.1, J040644.43+254018.1, J040651.36+254128.3 = V1195 Tau, J040716.73+240257.6, J040809.49+222434.8, J041141.34+261341.3, and J041240.69+243815.6).
4.2. Reddening
Figure 5 is another look at this same issue of contamination in the candidate list, this time through the lens of AV. The previously known YSOs are generally found in regions of high AV, and background galaxies are found in regions of low AV. As discussed above, we obtained a coarse estimate of AV based on a ∼6' × 6' box centered on the position of the object in a map constructed from 2MASS star counts (Froebrich et al. 2007). Figure 5 shows that the distribution of AV for the candidates is considerably closer to the distribution of AV for the contaminants rather than the previously known YSOs. The largest AV found for the recovered YSOs is 10.8 mag, and the largest AV for the candidates is only 3 mag (J042850.54+184436.1), with two others having AV > 2 (J042213.75+152529.9–AV = 2.6, J045141.49+305519.5–AV = 2.7). These may be among the highest likelihood YSOs on our candidate list. This analysis could indicate that our list of surviving candidate YSOs is substantially contaminated, or it could reflect instead the fact that all the searches to date (including our prior Spitzer survey) have focused on regions of high AV, and the "discovery space" is in the regions of lower AV.
Figure 5. Histogram of AV values (top two; middle is zoomed-in version of the top), and cumulative distribution of AV values (bottom), for recovered known YSOs (green, solid line), rejected contaminants (red, dotted line), and new YSO candidates (black, dashed line). The distribution of AV values for the candidates is much closer to the distribution of contaminants than previously known YSOs. The AV estimates come from a median ∼6' × 6' box centered on the position of the object.
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Standard image High-resolution imageFigure 6 shows the distribution of recovered YSOs, new YSO candidates, and rejected YSO candidates on the AV map from Froebrich et al. (2007). As inferred above, the rejected objects tend to be evenly distributed, and the recovered YSOs tend to be clustered in regions of high AV. The new objects are not particularly clustered, but not evenly distributed either. There is an apparent clump of objects in the northwest, toward Perseus (see also Figure 2); most of these objects have excesses only at 22 μm, which, as discussed below, may be a result of source confusion.
Figure 6. Locations of YSO candidates and recovered previously identified YSOs (left, purple and green, respectively) and rejected candidates (right) superimposed on an AV map constructed from 2MASS by Froebrich et al. (2007) with ∼4' resolution. The structure seen in the AV can be compared to that seen in IRAS 100 μm in Figure 2.
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Standard image High-resolution image4.3. W1 Brightnesses
The color cuts in Koenig et al. (2011) are performed in, among other color spaces, W1 versus W1−W4 ([3.4] versus [3.4]−[22]). This diagram, and its Spitzer analog ([3.6] versus [3.6]−[24]), has proven to be very useful in identifying YSO candidates (see, e.g., Rebull et al. 2010). Figure 7 shows this diagram for the 94 YSO candidates, rejected candidates, and recovered YSOs. Photospheres (stars without disks) would have a W1−W4 color near zero, and galaxies near W1 ∼ 16, W1−W4 ∼ 7, but they have already been removed by the Koenig et al. (2011) process. Most of the previously identified YSOs are bright, and most of the contaminants are faint. The new YSO candidates span the range of bright and faint.
Figure 7. W1 vs. W1−W4 ([3.4] vs. [3.4]−[22]) color–magnitude diagram for the recovered previously identified YSOs (+), the rejected candidates (×), and the best remaining YSO candidates (circles).
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Standard image High-resolution imageThe distribution of brightnesses at W1 (3.4 μm) can be seen explicitly in Figure 8. Figure 8 suggests a different conclusion than Figure 5; here, the new candidates are intermediate in cumulative brightness distribution between the previously known YSOs (brighter) and the contaminants (fainter). This assessment is reinforced by the formal values calculated for two-sided two-dimensional Kolmogorov–Smirnov tests. This is consistent with broad expectations; most of the background galaxies will be faint, most of the surveys to date will have found the bright YSOs, and the "discovery space" for new YSOs is on the faint end of the distribution of expected brightnesses for YSOs in Taurus. Unextincted YSOs in Taurus above the hydrogen burning limit should be no fainter than 13th magnitude at W1. Thus, fainter YSOs should show evidence of extinction, and much fainter ones could only be edge-on disks or more distant emission-line objects.
Figure 8. Histogram of W1 (3.4 μm values; top two, where middle is zoomed-in version of the top), and cumulative distribution of W1 values (bottom), for recovered known YSOs (green, solid line), rejected contaminants (red, dotted line), and new YSO candidates (black, dashed line). Unlike the AV distributions in the previous figure, here the distribution of values for the candidates much more similar to that for the previously known YSOs than that for the contaminants.
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Standard image High-resolution imageFigure 8 suggests that our YSO list is contaminated to a larger degree at the faint end of the distribution of 3.4 μm magnitudes. There is a small peak in the distribution of candidate magnitudes at the same location of the highest peak of contaminant magnitudes (W1 ∼ 13.5 mag), suggesting that the highest fraction of contaminants per bin will be found in those bins. Similar results are obtained for, e.g., a histogram of H magnitudes. However, it is worth noting that in our earlier studies of Taurus, we found a large number of bright background stars (e.g., AGBs) that appeared to have excesses, but are not members of Taurus.
4.4. Near-IR Colors
Figure 9 shows the JHKs color–color diagram for the 94 YSO candidates, rejected candidates, and recovered known YSOs. Consistent with expectations and with Figure 5 above, the distribution of the previously identified YSOs extends from the locus of normal young and accreting stars with near-infrared excesses in the direction of the reddening vector. Encouragingly, the distribution of contaminants is broad and generally consistent with non-stellar sources. Few of the YSO candidates have large values of AV, consistent with Figure 5. There are 11 objects with (H − Ks) > 0.75 and (J − H) > 1: J040204.41+251210.3, J040805.16+300627.6, J041419.20+220138.0, J043131.61+293819.0, J043327.90+175843.8, J044512.68+194501.1, J044719.33+325449.8, J044801.88+294902.1, J044813.48+292453.5, J045352.77+222813.7, and J045913.28+320201.3. These objects are in the right regime of the JHKs diagram to be higher-quality YSO candidates. However, as can be seen in the Appendix, we have no ancillary photometric data for most of these, and for the two where we do have such data, the WISE measurements do not agree with those from Akari (J044813.48+292453.5) or IRAC (J043131.61+293819.0 = 0431316+293818 in our Spitzer catalog). This is not generally the case—usually the WISE, Akari, and Spitzer measurements are in good agreement. One reason they might not agree would be the differing resolution of the instruments—if there is source confusion or the source is resolved (e.g., it is a likely galaxy), then the photometry would not agree. However, these objects are point sources in all of the images we examined. Another reason why the photometry might be different is that the young stars themselves may vary between epochs (see, e.g., Morales-Calderon et al. 2011, or Rebull 2011, and references therein). Additional observations are warranted.
Figure 9. JHKs color–color diagram for the recovered previously identified YSOs (+), the rejected candidates (×), and the best remaining YSO candidates (circles).
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Standard image High-resolution image4.5. Optical Data
The SDSS data do not extend over our entire studied region, but optical data can be very helpful in ruling out YSO candidates. There are matches to SDSS spectra for only 27 objects in our entire set, 15 of which are tagged galaxies (including known YSOs CoKu Tau/1 and GV Tau; presumably the SDSS pipeline is confused by emission lines in these sources). Eleven more of the SDSS spectra are for previously identified YSOs. Thirteen of the objects that we have placed in our "reject" list have SDSS spectra, all of which are galaxies. Just one of our surviving YSO candidates has an SDSS spectrum, and it is identified as an M5. Since our placement of objects on the reject or candidate YSO list was independent of the SDSS spectra, this is encouraging and suggests that our classification of the remaining objects without SDSS spectra may be correct on average.
There are SDSS z measurements for ∼26% of our entire set, but only ∼15% of our surviving YSO candidate list. Figure 10 shows the r versus (r − z) color–magnitude diagram for our objects. Most of the recovered known YSOs are in the expected location, e.g., to the red side in the diagram. Just four of our candidate YSOs are in the main portion of the distribution of known YSOs (J041240.69+243815.6, J041551.98+315514.0, J042625.87+351507.6, and J045808.02+251852.6). It is worth noting that the distribution of previously identified YSOs as well as candidates extends into the regime occupied by the contaminants on the blue side, but that all five of the previously identified YSOs in that area (r < 1.9 and (r − z) < 1.9) are actually unconfirmed YSOs from Rebull et al. (2010) (J041604.83+261800.9, J041810.60+284447.0, J041823.20+251928.0, J041858.99+255740.0, and J041940.48+270100.7), and may in the end turn out not to be Taurus members. The nine new YSO candidates in that regime may have a similar fate; they are J041141.34+261341.3, J041831.61+352732.7, J042146.44+240147.1, J042220.80+170812.0, J042659.19+183548.7, J043326.74+204758.7, J044428.98+201537.5, J045522.17+250923.2, and J045943.63+252647.2.
Figure 10. SDSS r vs. (r − z) in AB magnitudes for the recovered previously identified YSOs (+), the rejected candidates (×), and the best remaining candidates (circles). The main sequence from Bochanski et al. (2010) is the solid line. Legitimate Taurus objects could be below the main sequence as a result of edge on disks; in those cases, we are seeing scattered light from substantial infrared excesses viewed at a high inclination angle.
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Standard image High-resolution image4.6. Size of Infrared Excess
Since the WISE spatial resolution is relatively low, especially if there is an infrared excess seen only at 22 μm, one must be suspicious of source confusion. The long wavelength excess objects may also be the most interesting astrophysically, since they could have large inner disk holes. We have investigated each of the images and have not been able to identify source confusion. Objects that we have identified that have excesses only at 22 μm can be selected out of Figure 11. Objects with small Ks−W3 excesses (<2) generally also have small W1−W4 excesses, but the eleven that also have W1−W4 < 4 are the ones for which we are most suspicious of source confusion: J035958.81+312901.1, J040159.15+321941.2, J040651.36+254128.3, J041025.61+315150.7, J041752.27+360720.2, J041946.18+194539.8, J042954.77+291228.5, J045808.02+251852.6, J050357.98+265828.8, and J050450.13+264314.6.
Figure 11. W1−W4 ([3.4]−[22]) vs. Ks−W3 (Ks−[12]) for the recovered previously identified YSOs (+), the rejected candidates (×), and the best remaining candidates (circles).
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Standard image High-resolution image4.7. Distribution of SED Classifications
In Rebull et al. (2010), we compared a variety of YSO selection methods, and we also had enough ancillary data that we were able to categorize most of the objects that WISE sees in this overlap region; Figure 3 shows relatively few WISE-identified new YSO candidates in the region where we had Spitzer data (compare to Figure 1). In the region of Spitzer coverage, we can compare the selection statistics for the Koenig et al. (2011) method with that from Gutermuth et al. (2008, 2009). There are IRAC-1 measurements for ∼25% of our set. There are 210 for which we can calculate a Gutermuth et al. classification, 119 of which are recovered known YSOs. Both the Koenig et al. and Gutermuth et al. methods return SED classifications of objects. Table 4 shows a comparison of the methods. For the most part, the classifications agree—Gutermuth et al. identify relatively few of the sources as contaminants (9%), and both methods agree that 31% of the sample are Class I and 40% are Class II.
Table 4. Comparison of Gutermuth et al. (2008, 2009) and Koenig et al. (2011) Methods
| Koenig et al. Classification | Gutermuth et al. | Gutermuth et al. | Gutermuth et al. |
|---|---|---|---|
| Contaminant | Class 0/I | Class II | |
| Class I | 2 | 65 | 19 |
| Class II | 5 | 17 | 84 |
| Transition disk | 12 | 2 | 4 |
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Finally, we consider, among the objects we have recovered, rejected, or retained as YSO candidates, the distribution of classifications returned by the Koenig et al. (2011) method; see Table 5. The rejected sources are predominantly categorized as Class I candidates, consistent with the observation that many have very flat SEDs suggestive of extragalactic objects (or a reflection of our selection bias against very flat SEDs). The recovered YSOs are mostly categorized as Class II, consistent with what is already known in Taurus. The set of surviving YSO candidates is also mostly categorized as Class II objects.
Table 5. Breakdown of the Koenig et al. (2011) Classifications
| Sample | Class I | Class II | Transition Disk |
|---|---|---|---|
| Of the rejects (number) | 365 | 211 | 148 |
| Of the rejects (fraction) | 0.50 | 0.29 | 0.20 |
| Of the recovered (number) | 62 | 122 | 12 |
| Of the recovered (fraction) | 0.32 | 0.62 | 0.06 |
| Of the candidates (number) | 28 | 46 | 20 |
| Of the candidates (fraction) | 0.29 | 0.49 | 0.21 |
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5. CONCLUSIONS
We have presented the results of our search for new candidate Taurus members using 2MASS+WISE data over ∼260 deg2. We used NIR+MIR colors to select a set of YSO candidates following methodology presented by Koenig et al. (2011). We compared the resultant list of YSO candidates to our own catalog from Rebull et al. (2010), updated to include Taurus members not in our original Spitzer map, the 2MASS Extended Source Catalog, several SDSS stripes (photometry plus spectroscopy), and Akari data. We recover 196 previously identified young stars in the direction of Taurus with infrared excess and identify 686 objects that are confirmed or likely galaxies, 13 foreground or background stars, 1 PN, 24 objects likely subject to confusion based on inspection of the images, and 94 new YSO candidates. As was the case for our smaller Spitzer-based search for YSO candidates (Rebull et al. 2010), supporting ancillary data and manual inspection of the images and SEDs for each YSO candidate are critical. The YSO candidates are broadly distributed in (projected) space, unlike the previously identified YSOs, which are generally clustered. Few are in regions of high AV (again, unlike the recovered YSO sample), but they are generally fainter in 3.4 μm than the previously identified sample. There is likely to be contamination lingering in this list. We identify a few objects that are particularly likely to be legitimate YSOs, and a few that are particularly likely to be contaminants. Follow-up spectra to obtain spectral types and to search for emission lines and other indications of youth are warranted.
This publication makes use of data products from the Wide-field Infrared Survey Explorer, which is a joint project of the University of California, Los Angeles, and the Jet Propulsion Laboratory/California Institute of Technology, funded by the National Aeronautics and Space Administration. This research has made use of NASA's Astrophysics Data System (ADS) Abstract Service, and of the SIMBAD database, operated at CDS, Strasbourg, France. This research has made use of data products from the Two Micron All Sky Survey (2MASS), which is a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center, funded by the National Aeronautics and Space Administration and the National Science Foundation. These data were served by the NASA/IPAC Infrared Science Archive, which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration. This research has made use of the Digitized Sky Surveys, which were produced at the Space Telescope Science Institute under U.S. Government grant NAG W-2166. The images of these surveys are based on photographic data obtained using the Oschin Schmidt Telescope on Palomar Mountain and the UK Schmidt Telescope. The plates were processed into the present compressed digital form with the permission of these institutions.
The research described in this paper was partially carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
APPENDIX: SEDs FOR ALL OF THE CANDIDATES
For each of our new candidate Taurus members, we provide an SED here in Figure 12. Notation is as follows: "+"–literature Johnson photometry, "*"–Sloan photometry, "×"–CFHT photometry, diamonds–2MASS, circles–IRAC, stars–WISE, triangles–Akari, and squares–MIPS. Limits for any band, if available, are indicated by arrows. The wavelength is in microns; λFλ is in cgs units (erg s−1 cm−2). Each plot has the WISE catalog number, which can also be found in Table 3.
Figure 12.
SEDs for the new candidate members, shown here for J041551.98+315514. Notation is as follows: "+"–literature Johnson photometry, "*"–Sloan photometry, "×"–CFHT photometry, diamonds–2MASS, circles–IRAC, stars–WISE, triangles–Akari, squares–MIPS. Limits for any band, if available, are indicated by arrows. The wavelength is in microns; λFλ is in cgs units (erg s−1 cm−2). Each plot has the WISE catalog number, which can also be found in Table 3. (The complete figure set (94 images) is available in the online journal.)
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Standard image High-resolution imageNote added in proof: E. Mamajek, via private communication, notes that Tycho-2 and UCAC3 proper motions for several of the objects do not seem to have a proper motion consistent with the Taurus subgroups. The motions of HD 281395, 281479, 281664, 281789, 284346, and 284075 are all very small—they are probably background objects. HD 32509 is a previously known Ae star with IR excess—it seems to be an isolated young massive star with a disk, but its proper motion (pmRA, pmDec = +15, −32 mas yr−1) isn't similar to that of the group that it is nearest to (L1544; pmRA, pmDec = +0.9, −17.6 mas yr−1; Table 8 of Luhman et al. 2009). The clump near RA, Dec ∼ 60, +31 (HD 281395, 281479, 281664, 281789) might be members of Per OB2 association at d ∼ 300 pc.
Footnotes
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"D" denotes diffraction spike, "H" indicates that the source is spurious as a result of, or contaminated by, the scattered light halo surrounding a nearby bright source, "O" denotes optical ghost, and "P" denotes persistence artifact.