Validation of 13 Hot and Potentially Terrestrial TESS Planets

All of our TOIs were identified by the NASA Science Processing Operations Center (SPOC) pipeline (Jenkins et al. 2016), which analyzes data collected at a 2 minute or 20 s cadence. The SPOC pipeline identifies potential TOIs by conducting a search for transiting planet signatures using a wavelet-based, adaptive noise-compensating matched filter with the Transiting Planet Search (TPS; Jenkins 2002; Jenkins et al. 2010) algorithm. It then performs a limb-darkened transit model fit to the detected signatures (Li et al. 2019) and constructs a number of diagnostic tests to help assess the planetary nature of the detected signals (Twicken et al. 2018), which are compiled in data validation reports. The pipeline then removes the transits of each potential signature and calls TPS to detect additional transiting planet signatures, stopping when it fails to identify additional transits or reaches a limit of eight detected signatures. The SPOC pipeline generates two light curves for each TOI: light curves extracted via simple aperture photometry (SAP; Twicken et al. 2010; Morris et al. 2020), and light curves extracted via SAP with an additional presearch data conditioning step (PDCSAP; Stumpe et al. 2012; Smith et al. 2012; Stumpe et al. 2014). The PDC step aids in planet detection by removing background trends and flux contamination due to nearby bright stars, a process that is well established in exoplanet transit surveys (Stumpe et al. 2012).

While the SPOC pipeline typically generates light curves that are sufficient for analyzing transits, it is not designed to preserve out-of-transit variation originating from the system. Because we are interested in whether our planet candidates show evidence of phase curves caused by reflected light in the TESS data, we take a different approach to extracting light curves that detrends the instrument systematics and stellar rotation signal while preserving transits and potential secondary eclipses. First, using the same approach as that discussed in Hedges et al. (2021), we build design matrices consisting of (1) an estimate of the TESS scattered light background based on the top four principal components of the pixels outside of the optimum pipeline aperture, estimated via singular value decomposition, (2) a basis spline with a knot spacing of 0.25 days to capture stellar variability, (3) the centroids of the image in column and row dimension, (4) the single-scale cotrending basis vectors (CBVs) from the TESS pipeline, (5) a simple BLS transit model, at a fixed period, transit midpoint, and duration, and (6) a simple eclipse model, consisting of a cosine phase curve and a simple box eclipse at phase 0.5. Using the same methods from Hedges et al. (2020), we fit these design matrices to all sectors simultaneously, fitting a single transit and a single-eclipse model for all sectors but allowing each individual sector to have unique solutions for the background, spline, centroid, and CBV matrices. By taking this approach of fitting all the sectors simultaneously, we are the most sensitive to the small signal of eclipses, because all sectors are able to contribute to our eclipse measurement. Even with this rigorous approach, we detect no eclipse with a ≥3σ significance for the planet candidates in this paper.

Our light-curve generation code does not subtract out contamination due to nearby stars, which is an important step for correctly determining the radius of a planet candidate. However, because the code uses the same apertures as the SPOC pipeline, we are able to remove contamination using the crowding factor (labeled as CROWDSAP in the PDCSAP FITS headers) for each of our targets. We perform this subtraction when fitting the photometry for the orbital and physical parameters of the planet candidates, which is further described in Section 2.3.

We adopt stellar parameters for each of our host stars using a combination of spectrum analysis and empirical relation. The tools used to calculate stellar parameters from spectra are outlined in Section 4.2, and the empirical relations used to calculate stellar parameters are described below. Because different methods yield different parameters (e.g., some spectrum-based analysis methods only provide effective temperature and surface gravity, whereas others also provide estimates for stellar mass and radius), we take a curated approach for each of our stars. We describe this process in detail here and present the adopted parameters in Table 2.

When available, we use spectra to estimate T_eff. Where more than one spectrum-based estimate of T_eff is available, we adopt the average of the estimates. If spectra are not available, or if our stellar classification tools are unable to estimate parameters for a given star (which is sometimes the case for stars with T_eff ≤ 4500 K), we adopt the T_eff listed in the TIC.

For stars observed with Keck/HIRES and T_eff > 4250 K, we adopt the R_⋆ estimated from the spectrum. For all other stars with T_eff > 4250 K, we adopt the R_⋆ listed in the TIC. For all stars with T_eff ≤ 4250 K, we estimate R_⋆ and its uncertainties with the calibrations by Mann et al. (2015), using the 2MASS K_S-band magnitudes and Gaia/DR2 parallaxes.

For stars observed with Keck/HIRES and T_eff > 4700 K, we adopt the stellar mass (M_⋆) estimated from the spectrum. For all other stars with observed spectra and T_eff > 4250 K, we calculate M_⋆ using the R_⋆ listed in the TIC and the surface gravity estimated from the spectra. For all stars with T_eff ≤ 4250 K, we estimate M_⋆ with the near-infrared mass–luminosity calibrations in Mann et al. (2019) and Benedict et al. (2016; adopting the average of the two), using the 2MASS K_S-band magnitudes and Gaia/DR2 parallaxes.

For stars with observed spectra and T_eff > 4250 K, we adopt the surface gravity ($\mathrm{log}g$) estimated from the spectra. Where more than one spectrum-based estimate of $\mathrm{log}g$ is available, we adopt the average of the estimates. For all other stars, $\mathrm{log}g$ is calculated using the values of M_⋆ and R_⋆ determined with the methods described above.

To estimate the orbital and planetary parameters for each of our planet candidates, we fit each of our light curves with Markov Chain Monte Carlo sampling using the exoplanet (Foreman-Mackey et al. 2021) Python package. Our transit model assumed a circular orbit and was initialized with the following priors: (1) Gaussian priors for M_⋆ and R_⋆, (2) a Gaussian prior for the natural logarithm of P_orb, (3) a Gaussian prior for the time of inferior conjunction (T₀), (4) a uniform prior for the impact parameter (b), (5) uniform priors for quadratic limb-darkening coefficients (Kipping 2013), (6) a Gaussian prior for the natural logarithm of the transit depth, and (7) a Gaussian prior for the flux zero point of the light curve. For each TOI, we run a 10 walker ensemble for 20,000 steps and ensure that convergence was achieved, then discard the first 10,000 steps as burn-in. The best-fit parameters for each planet candidate are shown in Table 3, and the corresponding best-fit light-curve models are shown in Figure 1.

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Table 2. Adopted Stellar Parameters

TOI	Teff (K)	$\mathrm{log}g$	M⋆ (M⊙)	R⋆ (R⊙)
206	3383 ± 157	4.89 ± 0.03	0.35 ± 0.01	0.35 ± 0.01
500	4621 ± 50	4.63 ± 0.10	0.88 ± 0.25	0.75 ± 0.06
539	5031 ± 50	4.58 ± 0.10	0.91 ± 0.24	0.81 ± 0.05
544	4369 ± 100	4.73 ± 0.10	0.85 ± 0.20	0.66 ± 0.02
731	3540 ± 160	4.79 ± 0.03	0.48 ± 0.03	0.46 ± 0.01
833	3920 ± 160	4.67 ± 0.04	0.61 ± 0.03	0.60 ± 0.02
1075	3921 ± 157	4.69 ± 0.03	0.60 ± 0.02	0.58 ± 0.02
1242	4348 ± 100	4.69 ± 0.10	0.83 ± 0.31	0.68 ± 0.10
1263	5166 ± 50	4.54 ± 0.10	0.78 ± 0.20	0.82 ± 0.05
1411	4266 ± 100	4.73 ± 0.10	0.59 ± 0.23	0.66 ± 0.10
1442	3330 ± 160	4.92 ± 0.04	0.29 ± 0.02	0.31 ± 0.01
1693	3499 ± 70	4.80 ± 0.03	0.49 ± 0.03	0.46 ± 0.01
1860	5752 ± 100	4.58 ± 0.10	0.99 ± 0.03	0.94 ± 0.02
2260	5534 ± 100	4.62 ± 0.10	0.99 ± 0.04	0.94 ± 0.05
2290	3813 ± 70	4.70 ± 0.02	0.56 ± 0.01	0.57 ± 0.02
2411	4099 ± 123	4.59 ± 0.03	0.65 ± 0.02	0.68 ± 0.02
2427	4072 ± 121	4.62 ± 0.03	0.64 ± 0.02	0.65 ± 0.02
2445	3333 ± 157	4.97 ± 0.04	0.25 ± 0.01	0.27 ± 0.01

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For most of the TOIs in this paper, these fits only include TESS data. However, transits of TOI-206.01, TOI-1075.01, TOI-1442.01, TOI-1693.01, TOI-2411.01, TOI-2411.01, TOI-2427.01, and TOI-2445.01 were also observed by ground-based telescopes. For these targets, we perform joint fits including both the TESS data and the ground-based data. We fit for limb-darkening coefficients, transit depth, and flux zero point independently for each data set while treating M_⋆, R_⋆, P_orb, T₀, and b as parameters that are shared between the data sets. The ground-based data are discussed in Section 4.3. In these cases, we adopt the planet radii inferred from the TESS data.

Using these new planet properties, we recalculate the ESM for each TOI. All TOIs except for TOI-206.01, TOI-500.01, TOI-539.01, and TOI-1693.01 retained an ESM > 7.5. In addition, we find that TOI-544.01 may have a radius slightly larger than 2R_⊕. Even though these TOIs do not meet our initial selection criteria with their newly calculated properties, we keep them in our analysis.

We obtained high-resolution images of our TOIs using adaptive optics, speckle, and lucky imaging. In each of these observations, we search for stars within 5'' from the target star. In situations where companions were detected, we cross-checked the TIC to determine if these companions were previously known. These observations, which were obtained by members of TFOP Sub Group 3 (SG3), are summarized in Table 4, displayed in Figure 2, and discussed below.

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Table 4. Summary of High-resolution Imaging Follow-up

TOI	Telescope	Instrument	Filter	Image Type	Companion	Contrast (Δmag)
					(<5'')	01	05	10	15	20
206	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.625	4.323	4.641	4.958	5.275
	Gemini-S (8 m)	Zorro	562 nm	Speckle	⋯	4.115	4.398	4.309	⋯	⋯
	Gemini-S (8 m)	Zorro	832 nm	Speckle	⋯	4.908	5.787	6.081	⋯	⋯
500	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.721	4.738	5.164	5.591	6.017
	Gemini-S (8 m)	Zorro	562 nm	Speckle	⋯	5.307	6.083	6.564	⋯	⋯
	Gemini-S (8 m)	Zorro	832 nm	Speckle	⋯	5.057	6.441	7.386	⋯	⋯
539	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.660	5.238	5.462	5.686	5.910
544	CAHA (2.2 m)	AstraLux	SDSSz	Lucky	⋯	2.614	6.015	4.053	⋯	⋯
	Shane (3 m)	ShARCS	Ks	AO	⋯	0.588	3.272	4.774	5.816	6.625
	Shane (3 m)	ShARCS	J	AO	⋯	0.842	3.223	4.713	5.940	6.872
	WIYN (3.5 m)	NESSI	562 nm	Speckle	⋯	1.817	4.431	4.856	⋯	⋯
	WIYN (3.5 m)	NESSI	832 nm	Speckle	⋯	1.646	5.025	5.933	⋯	⋯
	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.903	5.370	5.629	5.887	6.145
731	Gemini-S (8 m)	DSSI	692 nm	Speckle	⋯	4.721	6.998	7.872	⋯	⋯
	Gemini-S (8 m)	DSSI	880 nm	Speckle	⋯	4.498	6.470	6.889	⋯	⋯
833	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.922	5.068	5.285	5.503	5.720
	Gemini-S (8 m)	Zorro	562 nm	Speckle	⋯	4.319	4.752	4.932	⋯	⋯
	Gemini-S (8 m)	Zorro	832 nm	Speckle	⋯	5.162	6.805	8.119	⋯	⋯
1075	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.708	4.990	5.310	5.631	5.9518
	Gemini-S (8 m)	Zorro	562 nm	Speckle	⋯	4.061	4.278	4.429	⋯	⋯
	Gemini-S (8 m)	Zorro	832 nm	Speckle	⋯	5.009	5.653	6.126	⋯	⋯
1242	CAHA (2.2 m)	AstraLux	SDSSz	Lucky	⋯	2.143	4.128	4.047	3.898	⋯
	Shane (3 m)	ShARCS	Ks	AO	Y	0.438	2.039	3.549	4.641	5.567
	Shane (3 m)	ShARCS	J	AO	Y	0.237	1.186	2.313	3.304	4.055
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	3.718	3.980	4.017	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.551	6.087	6.856	⋯	⋯
1263	WIYN (3.5 m)	NESSI	562 nm	Speckle	⋯	1.690	3.799	4.049	⋯	⋯
	WIYN (3.5 m)	NESSI	832 nm	Speckle	⋯	1.679	5.066	5.533	⋯	⋯
	SOAR (4.1 m)	HRCam	Ic	Speckle	Y	1.782	4.081	4.565	5.049	5.532
	Palomar (5 m)	PHARO	Brγ	AO	Y	1.716	6.869	8.648	9.145	9.275
	Palomar (5 m)	PHARO	Hcont	AO	Y	1.986	7.769	8.965	9.618	9.685
1411	CAHA (2.2 m)	AstraLux	SDSSz	Lucky	⋯	2.368	4.425	4.461	4.309
	Palomar (5 m)	PHARO	Brγ	AO	⋯	1.789	6.912	8.190	9.017	9.241
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	4.333	5.609	5.877	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.414	7.160	8.496	⋯	⋯
	Keck (10 m)	NIRC2	Ks	AO	⋯	3.892	7.574	8.308	8.317	8.312
1442	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	3.644	3.867	4.060	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.703	5.622	6.118	⋯	⋯
	Keck (10 m)	NIRC2	K	AO	⋯	3.905	7.638	7.801	7.837	7.782
1693	Shane (3 m)	ShARCS	Ks	AO	⋯	0.610	2.790	4.155	5.208	6.081
	Palomar (5 m)	PHARO	Brγ	AO	⋯	2.751	6.982	8.411	8.847	8.916
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	4.380	4.803	4.958	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.979	6.440	7.443	⋯	⋯
1860	Shane (3 m)	ShARCS	Brγ	AO	⋯	0.592	3.287	4.598	5.096	5.669
	Palomar (5 m)	PHARO	Brγ	AO	⋯	2.366	6.873	8.346	8.984	9.051
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	4.659	5.327	5.631	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.984	7.356	8.978	⋯	⋯
2260	CAHA (2.2 m)	AstraLux	SDSSz	Lucky	⋯	2.456	5.399	5.666	⋯	⋯
	SAI (2.5 m)	SPP	Ic	Speckle	⋯	2.548	5.293	6.406	⋯	⋯
	Shane (3 m)	ShARCS	Ks	AO	⋯	0.564	2.740	4.142	5.139	6.027
	Shane (3 m)	ShARCS	J	AO	⋯	0.547	2.345	3.799	5.040	5.968
	Palomar (5 m)	PHARO	Brγ	AO	⋯	2.875	6.920	8.418	8.983	9.106
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	4.688	5.674	6.283	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.539	6.577	8.384	⋯	⋯
2290	SAI (2.5 m)	SPP	Ic	Speckle	⋯	1.207	5.176	6.509	⋯	⋯
	Gemini-N (8 m)	'Alopeke	562 nm	Speckle	⋯	3.740	4.231	4.424	⋯	⋯
	Gemini-N (8 m)	'Alopeke	832 nm	Speckle	⋯	4.965	6.128	7.071	⋯	⋯
	Keck (10 m)	NIRC2	K	AO	⋯	3.755	7.169	7.276	7.254	7.181
2411	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.844	5.776	6.031	6.286	6.541
	Palomar (5 m)	PHARO	Brγ	AO	⋯	2.566	7.197	8.199	8.637	8.712
	Keck (10 m)	NIRC2	Brγ	AO	⋯	3.906	6.505	6.552	6.476	6.483
2427	SOAR (4.1 m)	HRCam	Ic	Speckle	⋯	1.955	5.434	5.758	6.083	6.408
	Keck (10 m)	NIRC2	Brγ	AO	⋯	3.949	5.908	5.972	5.891	5.922
2445	Palomar (5 m)	PHARO	Brγ	AO	⋯	2.608	6.876	7.527	7.571	7.623
	Keck (10 m)	NIRC2	K	AO	⋯	3.955	6.939	6.904	6.912	6.895

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4.1.1. CAHA/AstraLux

4.1.2. SAI/SPP

4.1.3. WIYN/NESSI

4.1.4. SOAR/HRCam

4.1.5. Shane/ShARCS

4.1.6. Palomar/PHARO

4.1.7. Gemini-N/'Alopeke, Gemini-S/Zorro, and Gemini-S/DSSI

4.1.8. Keck/NIRC2

We obtained reconnaissance spectra of several of our TOIs to search for evidence of FPs and characterize the target stars. These spectra were obtained by members of TFOP Sub Group 2 (SG2). The observations and the stellar parameters extracted from the acquired spectra are summarized in Table 5. Further details on the observations and the analyses performed to search for FP signatures and characterize the stars are provided below.

Table 5. Summary of Reconnaissance Spectroscopy Follow-up and Derived Stellar Parameters

TOI	Telescope	Instrument	Nobs	Teff (K)	$\mathrm{log}g$	M⋆ (M⊙)	R⋆ (R⊕)	[Fe/H]	[M/H]	$v\sin i$ (km s−1)
500	SMARTS (1.5 m)	CHIRON	2	4621 ± 50	4.63 ± 0.10	⋯	⋯	⋯	−0.22 ± 0.10	2.00 ± 0.50
539	SMARTS (1.5 m)	CHIRON	2	5031 ± 50	4.58 ± 0.10	⋯	⋯	⋯	−0.14 ± 0.10	3.30 ± 0.50
544	SMARTS (1.5 m)	CHIRON	4	⋯	⋯	⋯	⋯	⋯	⋯	⋯
	FLWO (1.5 m)	TRES	2	4369 ± 100	4.73 ± 0.10	⋯	⋯	⋯	−0.42 ± 0.08	1.80 ± 0.50
731	SMARTS (1.5 m)	CHIRON	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
833	SMARTS (1.5 m)	CHIRON	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
1075	SMARTS (1.5 m)	CHIRON	1	⋯	⋯	⋯	⋯	⋯	⋯	⋯
1242	FLWO (1.5 m)	TRES	2	4437 ± 100	4.69 ± 0.10	⋯	⋯	⋯	−0.13 ± 0.08	3.60 ± 0.50
	Keck (10 m)	HIRES	2	4259 ± 70	⋯	⋯	0.68 ± 0.10	0.00 ± 0.09	⋯	⋯
1263	FLWO (1.5 m)	TRES	1	5160 ± 50	4.58 ± 0.10	⋯	⋯	⋯	0.04 ± 0.08	2.10 ± 0.50
	NOT (2.56 m)	FIES	4	5172 ± 50	4.50 ± 0.10	⋯	⋯	⋯	0.00 ± 0.08	0.60 ± 0.50
1411	FLWO (1.5 m)	TRES	2	4352 ± 100	4.73 ± 0.10	⋯	⋯	⋯	−0.37 ± 0.08	2.00 ± 0.50
	Keck (10 m)	HIRES	2	4180 ± 70	⋯	⋯	0.66 ± 0.10	0.10 ± 0.09	⋯	⋯
1693	FLWO (1.5 m)	TRES	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
	Keck (10 m)	HIRES	1	3466 ± 70	⋯	⋯	0.44 ± 0.10	0.03 ± 0.09	⋯	⋯
1860	NOT (2.56 m)	FIES	1	5780 ± 50	4.54 ± 0.10	⋯	⋯	⋯	−0.09 ± 0.08	11.10 ± 0.50
	Keck (10 m)	HIRES	1	5724 ± 100	4.61 ± 0.10	0.99 ± 0.03	0.94 ± 0.02	0.04 ± 0.06	⋯	10.37 ± 1.00
2260	Keck (10 m)	HIRES	1	5534 ± 100	4.62 ± 0.10	0.99 ± 0.04	0.94 ± 0.05	0.22 ± 0.06	⋯	5.05 ± 1.00
2290	FLWO (1.5 m)	TRES	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
	Keck (10 m)	HIRES	1	3813 ± 70	⋯	⋯	0.57 ± 0.10	−0.03 ± 0.09	⋯	⋯
2411	SMARTS (1.5 m)	CHIRON	3	⋯	⋯	⋯	⋯	⋯	⋯	⋯
	FLWO (1.5 m)	TRES	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
2427	SMARTS (1.5 m)	CHIRON	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯
	FLWO (1.5 m)	TRES	2	⋯	⋯	⋯	⋯	⋯	⋯	⋯

Note. Spectrum-derived parameters for each TOI. Entries that list no stellar parameters correspond to stars too cool to have parameters extracted using data collected with the specified instrument. More details on how these parameters were derived are in Section 4.2.

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4.2.1. FLWO/TRES and NOT/FIES

4.2.2. SMARTS/CHIRON

4.2.3. Keck/HIRES

To determine whether or not the signal observed by TESS is on the presumed target star and to help eliminate FPs from blends, we compile a set of observations collected by members of TFOP Sub Group 1 (SG1). These follow-up observations were scheduled using the TESS Transit Finder, which is a customized version of the Tapir software package (Jensen 2013). A summary of these observations is given in Table 7 and details about the facilities used are given in Table 8.

Table 7. Summary of Time-series Photometry Follow-up

TOI	TIC ID	Telescope	Date (UT)	Filter(s)
206.01	55650590	LCO 1.0 m	2018-11-19	${r}^{{\prime} }$
		SLR2	2018-11-22	V
		LCO 1.0 m	2018-11-23	${i}^{{\prime} }$
		CKD700	2018-11-30	${r}^{{\prime} }$
		LCO 1.0 m	2018-12-01	${r}^{{\prime} }{i}^{{\prime} }$
		LCO 1.0 m	2018-12-02	${i}^{{\prime} }$
		LCO 1.0 m	2018-12-06	${r}^{{\prime} }$
		LCO 1.0 m	2018-12-09	${i}^{{\prime} }$
500.01	134200185	LCO 1.0 m	2019-03-15	${r}^{{\prime} }$
		TRAPPIST-S.	2019-03-24	B
		LCO 0.4 m	2019-03-30	${i}^{{\prime} }$
		PEST	2019-03-30	Rc
		LCO 1.0 m	2019-05-02	zs
539.01	238004786	PEST	2019-03-29	Rc
		MKO CDK700	2019-03-31	${r}^{{\prime} }$
		LCO 1.0 m	2019-04-06	${i}^{{\prime} }$
		LCO 1.0 m	2019-04-08	zs
		LCO 1.0 m	2019-04-17	${i}^{{\prime} }$
544.01	50618703	LCO 1.0 m	2019-09-20	zs
		TCS	2019-10-13	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }$
731.01	34068865	LCO 1.0 m	2019-06-10	V
		MKO CDK700	2019-06-11	${i}^{{\prime} }$
		PEST	2020-01-05	Rc
		LCO 1.0 m	2020-05-12	zs
833.01	362249359	LCO 1.0 m	2020-03-28	zs
		LCO 1.0 m	2020-05-14	zs
		MKO CDK700	2020-05-15	${i}^{{\prime} }$
1075.01	351601843	LCO 1.0 m	2019-08-25	zs
		LCO 1.0 m	2019-08-26	zs
		MEarth-S	2019-09-22	RG715
		LCO 1.0 m	2019-09-23	zs
		LCO 1.0 m	2019-09-24	zs
		LCO 1.0 m	2019-09-26	zs
		MEarth-S	2019-09-28	RG715
1242.01	198212955	TCS	2020-01-27	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		TCS	2020-02-01	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		TCS	2020-02-09	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		ULMT	2020-05-18	${i}^{{\prime} }$
		TCS	2020-06-09	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
1263.01	406672232	LCO 1.0 m	2020-06-15	zs
		LCO 1.0 m	2020-07-28	zs
1411.01	116483514	LCO 1.0 m	2020-02-28	${i}^{{\prime} }$
		DSW CDK500	2020-04-16	${r}^{{\prime} }$
		TCS	2020-04-21	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		LCO 1.0 m	2020-04-29	${r}^{{\prime} }$
		ULMT	2020-05-02	${i}^{{\prime} }$
		TCS	2020-05-10	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
1442.01	235683377	OMM 1.6 m	2020-02-09	${i}^{{\prime} }$
		LCO 1.0 m	2020-08-14	${i}^{{\prime} }$
		LCO 1.0 m	2020-08-30	Ic
		LCO 1.0 m	2020-09-26	${i}^{{\prime} }$
		LCO 2.0 m	2021-05-21	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		LCO 2.0 m	2021-06-06	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
		LCO 2.0 m	2021-06-17	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
1693.01	353475866	LCO 1.0 m	2020-02-14	zs
		LCO 1.0 m	2020-10-11	zs
		TCS	2020-09-18	${g}^{{\prime} }{i}^{{\prime} }{z}_{s}$
1860.01	202426247	Adams	2020-06-06	Ic
		TCS	2020-07-20	${g}^{{\prime} }{r}^{{\prime} }{i}^{{\prime} }{z}_{s}$
2260.01	232568235	TRAPPIST-N	2020-09-28	${z}^{{\prime} }$
		Adams	2021-06-26	Ic
2290.01	321688498	LCO 1.0 m	2020-10-15	${i}^{{\prime} }$
2411.01	10837041	MKO CDK700	2021-01-13	${i}^{{\prime} }$
		LCO 1.0 m	2021-06-19	${r}^{{\prime} }$
		LCO 1.0 m	2021-07-10	${i}^{{\prime} }$
		LCO 1.0 m	2021-07-25	${i}^{{\prime} }$
		LCO 1.0 m	2021-08-27	${i}^{{\prime} }$
		LCO 1.0 m	2021-08-29	${i}^{{\prime} }$
		LCO 1.0 m	2021-08-30	${i}^{{\prime} }$
		LCO 1.0 m	2021-09-09	${i}^{{\prime} }$
2427.01	142937186	PEST	2021-01-12	Rc
		LCO 1.0 m	2021-01-30	zs
		LCO 1.0 m	2021-02-22	zs
		LCO 1.0 m	2021-08-14	zs
		LCO 1.0 m	2021-08-17	zs
2445.01	439867639	MLO	2021-01-10	Ic
		TRAPPIST-S	2021-01-08	I + z
		TRAPPIST-S	2021-01-14	I + z
		NAOJ 188 cm	2021-02-07	${g}^{{\prime} }{r}^{{\prime} }{z}_{s}$

Download table as:  ASCIITypeset images: 1 2

We search for transits around the target stars in our observations using the Bayesian Information (Schwarz 1978), considering a transit detected if a transit model is preferred over a flat line. For several of our TOIs, transits were verified on target using these observations. These cases are further described below. We incorporate these data into the transit fits described in Section 2.3 to obtain tighter constraints on the ephemerides of the planet candidates.

4.3.1. LCO 1.0 m/Sinistro

We observed full transits of TOI-206.01, TOI-1075.01, TOI-1442.01, TOI-1693.01, TOI-2411.01, and TOI-2427.01 using the Sinistro cameras on the Las Cumbres Observatory (LCO) 1.0 m telescopes. Images were calibrated by the standard LCOGT BANZAI pipeline (McCully et al. 2018), and the photometric data were extracted using the AstroImageJ (AIJ) software package (Collins et al. 2017). (Brown et al. 2013).

Transits of TOI-206.01 were observed with an $i^{\prime}$ filter on UT 2018 November 23, 2018 December 1, and 2018 December 9 and were found to have a depth of ∼1.0–1.5 ppt. Transits of TOI-1075.01 were observed with a z_s filter on UT 2019 August 26, 2019 September 23, 2019 September 24, and 2019 September 26 and were found to have a depth of ∼0.5–1.0 ppt. Transits of TOI-1442.01 were observed with an $i^{\prime}$ filter on UT 2020 August 14, 2020 September 26, and 2020 October 21 and were found to have a depth of ∼1.0–2.0 ppt. Transits of TOI-1693.01 were observed with a z_s filter on UT 2020 February 14 and 2020 October 11 and were found to have a depth of ∼0.5–1.0 ppt. Transits of TOI-2441.01 were observed with an $i^{\prime}$ filter on UT 2021 July 10, 2021 July 25, 2021 August 27, 2021 August 29, 2021 August 30, and 2021 September 9 and were found to have a depth of ∼0.25–0.75 ppt. Transits of TOI-2427.01 were observed with a z_s filter on UT 2021 August 14 and 2021 August 17 and were found to have a depth of ∼0.25–0.75 ppt. The data for each of these TOIs can be seen in Figures 3–9.

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4.3.2. MEarth-South

We observed full transits of TOI-1075.01 on UT 2019 September 22 and 2019 September 28 using the MEarth-South telescope array at the Cerro Tololo Inter-American Observatory (Nutzman & Charbonneau 2008; Irwin et al. 2015). The observations were collected with an RG715 filter and were found to have a transit depth of ∼0.5–1.0 ppt. The data can be seen in Figure 4.

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4.3.3. OMM 1.6 m/PESTO

We observed a full transit of TOI-1442.01 on UT 2020 February 9 using the PESTO camera installed at the 1.6 m Observatoire du Mont-Mégantic (OMM), Canada. PESTO is equipped with a 1024 × 1024 EMCCD detector with a scale of 0466 per pixel, providing an FOV of 795 × 795. The observations were collected with an $i^{\prime}$ filter and with a 30 s exposure time. Image calibrations, including bias subtraction and flat-field correction, and differential aperture photometry were performed with AstroImageJ (Collins et al. 2017). The events were observed with an $i^{\prime}$ filter and were found to have a transit depth of ∼1 ppt. The data can be seen in Figure 5.

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4.3.4. TRAPPIST-South

4.3.5. NAOJ 188 cm/MuSCAT, TCS/MuSCAT2, and LCO 2.0 m/MuSCAT3

We observed transits of TOI-1442.01, TOI-1693.01, and TOI-2445.01 using the MuSCAT, MuSCAT2, and MuSCAT3 instruments (Narita et al. 2015, 2019, 2020), which collect simultaneous observations using several filters. We observed full transits of TOI-1442.01 on UT 2021 May 21, 2021 June 6, and 2021 June 17 using MuSCAT3 on the LCO 2.0 m telescope at Haleakala Observatory. Observations were collected with the $g^{\prime}$, $r^{\prime}$, $i^{\prime}$, and z_s filters and measured a transit depth of ∼1.0–2.0 ppt. We observed a full transit of TOI-1693.01 on UT 2020 September 18 using MuSCAT2 on the Telescopio Carlos Sánchez (TCS) at Teide Observatory. Observations were collected with $g^{\prime}$, $i^{\prime}$, and z_s filters and measured a transit depth of ∼0.5–1.0 ppt. We observed a full transit of TOI-2445.01 on UT 2021 February 7 using MuSCAT on the National Astronomical Observatory of Japan (NAOJ) 188 cm telescope. Observations were collected with the $g^{\prime}$, $r^{\prime}$, and z_s filters and measured a transit depth of ∼1.0–5.0 ppt. These data can be seen in Figure 5, Figure 6, and Figure 10.

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TOI-206.01 is a 1.30 ± 0.05 R_⊕ planet candidate with a 0.74 day orbital period orbiting an M dwarf (TIC 55650590) that is 47.7 pc away and has a V magnitude of 14.94. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.04, indicating that the star is quiet. TOI-206 has been observed in 26 TESS sectors (1–13 and 27–39).

Follow-up observations have found no evidence of this TOI being an FP, although no spectroscopic observations have been collected. Time-series photometric follow-up has made several detections of the transit of TOI-206.01 on TIC 55650590 (shown in Figure 3).

The DAVE analysis of this TOI detects a potential secondary eclipse in the TESS light curve, which could indicate that the transit is due to an eclipsing binary. Because follow-up observations do not detect a companion star that could dilute the radius of the transiting object and because the transit was detected on target, this eclipsing binary would need to have a grazing transit. The morphology of the transit shown in Figure 1 is inconsistent with that of a grazing eclipsing binary, meaning the feature detected in the TESS photometry is unlikely to be an actual secondary eclipse. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (2.02 ± 1.48) × 10⁻⁵. Because all neighboring stars have been cleared, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-206 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.1}_{-1.0}^{+2.0}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.2}_{-0.7}^{+1.4}\,{M}_{\oplus }$.

TOI-500.01 is a 1.16 ± 0.12 R_⊕ planet candidate with a 0.55 day orbital period orbiting a K dwarf (TIC 134200185) that is 47.4 pc away and has a V magnitude of 10.54. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.007, indicating that the star is quiet. This is corroborated by the low $v\sin i$ extracted from our CHIRON spectra. TOI-500 has been observed in six TESS sectors (6–8 and 33–35).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit but has not yet detected the 0.23 ppt event seen in the TESS data around the target star.

DAVE finds no strong indicators that the candidate is an FP. We note, though, that the photocenter offset analysis performed by DAVE suffers from low S/N and poor quality in most of the per-transit difference images. As a result, there is a large scatter in the measured photocenters for each individual transit, making it difficult for DAVE to detect a significant photocenter offset. The SPOC data validation report, however, does detect significant centroid offsets in sectors 8, 34, and 35. No offsets were detected in sectors 7 or 33 by SPOC, and no data validation report was generated by the SPOC pipeline for sector 6. Given that all neighboring stars have been cleared from being nearby eclipsing binaries, these offsets are unlikely to be caused by an FP originating from a nearby star.

The TRICERATOPS analysis of this TOI finds FPP = (7.12 ± 1.13) × 10⁻³. Because all neighboring stars have been cleared, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-500 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={1.4}_{-0.7}^{+1.1}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={1.6}_{-0.7}^{+1.3}\,{M}_{\oplus }$.

TOI-539.01 is a 1.25 ± 0.10 R_⊕ planet candidate with a 0.31 day orbital period orbiting a K dwarf (TIC 238004786) that is 108.4 pc away and has a V magnitude of 11.73. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.07, indicating that the star is quiet. This is corroborated by the low $v\sin i$ extracted from our CHIRON spectrum. TOI-539 has been observed in 11 TESS sectors (2, 6, 8, 9, 12, 29, 32–35, and 39).

Follow-up observations have found no evidence of this TOI being an F. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit except for TIC 767067264, which is 72 west and 7.9 mag fainter in the Gaia G_Rp band. This nearby star appears not to show an event of the necessary depth but is not cleared at high confidence. The 0.31 ppt event seen in the TESS data has not been detected around the target star.

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. However, like TOI-500 b, the per-transit difference images used by DAVE have very low S/N and the measured photocenters are unreliable. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (3.98 ± 0.03) × 10⁻² and NFPP = (7.76 ± 0.26) × 10⁻²². This >1% FPP comes from the scenario that the TOI is a blended eclipsing binary. While this NFPP indicates that this TOI is unlikely to originate from the nearby star TIC 767067264, the FPP is too high to validate the planet candidate.

Assuming this is a real planet, we estimate the semiamplitude of its RV signal to be ${K}_{\mathrm{RV}}={1.9}_{-0.7}^{+1.6}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={1.9}_{-0.7}^{+1.6}\,{M}_{\oplus }$.

TOI-544.01 is a 2.03 ± 0.10 R_⊕ planet candidate with a 1.55 day orbital period orbiting a K dwarf (TIC 50618703) that is 41.1 pc away and has a V magnitude of 10.78. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.25, indicating that the star is quiet. This is corroborated by the low $v\sin i$ extracted from our TRES spectrum. TOI-544 has been observed in 2 TESS sectors (6 and 32).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit except for TIC 713009339 (located 526 south-southeast and 9.5 mag fainter in the TESS band) and TIC 50618707 (located 918 east-southeast and 6.9 mag fainter in the TESS band). TIC 713009339 is too faint to be the source of an astrophysical FP, but TIC 50618707 is not. We would like to note that the former of these nearby stars was detected by Gaia but not by 2MASS, while the latter was detected by 2MASS but not by Gaia. The parallaxes and proper motions of these two stars are unknown, so it is possible that they are the same star observed at two different epochs. If this were the case, the star would have been within the ∼10'' × 10'' FOV of the Shane/ShARCS observations obtained on UT 2019 September 13, which reach contrasts of >8 mags in the K_s and J bands. However, no stars other than TIC 50618703 were detected in these observations. If this star (or stars, if they are indeed different sources) are really there, it (or they) would be far too faint to host eclipsing binaries mistakable for the TOI-544.01 transit. Regardless, we consider these two nearby stars in the remaining vetting steps for the sake of completeness.

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (8.25 ± 0.91) × 10⁻³ and NFPP = (1.67 ± 0.16) × 10⁻¹⁶. This FPP and NFPP are sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-544 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.2}_{-1.4}^{+2.4}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={5.0}_{-2.0}^{+4.0}\,{M}_{\oplus }$.

TOI-731.01 is a 0.59 ± 0.02 R_⊕ planet candidate with a 0.32 day orbital period orbiting a high-proper-motion (μ_α = −462.5 mas yr⁻¹, μ_δ = −582.8 mas yr⁻¹) M dwarf (TIC 34068865) that is 9.4 pc away and has a V magnitude of 10.15. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.07, indicating that the star is quiet. TOI-731 has been observed in three TESS sectors (9, 35, and 36).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as transit sources except for TIC 34068883, which is 6.2 mag fainter in Gaia G_Rp and was 64 southwest at epoch 2020.361. ⁸⁶ However, this follow-up has not detected the 0.24 ppt transit around the target star that is seen in the TESS data.

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. Compared to TOI-500, the S/N of the per-transit difference images used by DAVE is even lower, and the measured centroids are unreliable. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (1.89 ± 0.46) × 10⁻² and NFPP = (9.21 ± 1.48) × 10⁻²⁶. This >1% FPP comes from the scenario that the TOI is a blended eclipsing binary. This FPP is too high to consider the planet candidate validated.

Assuming this is a real planet, we estimate the semiamplitude of the RV signal to be ${K}_{\mathrm{RV}}={0.22}_{-0.07}^{+0.11}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={0.15}_{-0.04}^{+0.07}\,{M}_{\oplus }$.

TOI-833.01 is a 1.27 ± 0.07 R_⊕ planet candidate with a 1.04 day orbital period orbiting a K dwarf (TIC 362249359) that is 41.7 pc away and has a V magnitude of 11.72. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.20, indicating that the star is quiet. TOI-833 has been observed in 5 TESS sectors (9, 10, 11, 36, and 37).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has made tentative detections of a ∼0.8–0.9 ppt transit on two different occasions. The field around this TOI is crowded, and it is not clear if the event is on target or due to blending with TIC 847323367 (located 31 north and 7.9 mag fainter in the TESS band).

The DAVE analysis of this TOI detects a potential centroid offset to the northeast but found no other indicators that this TOI is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (2.32 ± 0.23) × 10⁻⁴ and NFPP = (3.89 ± 0.11) × 10⁻¹⁰. This FPP and NFPP are sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-833 b. We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={1.8}_{-0.5}^{+1.3}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.0}_{-0.6}^{+1.5}\,{M}_{\oplus }$.

TOI-1075.01 is a 1.72 ± 0.08 R_⊕ planet candidate with a 0.60 day orbital period orbiting a K dwarf (TIC 351601843) that is 61.5 pc away and has a V magnitude of 12.62. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.02, indicating that the star is quiet. TOI-1075 has been observed in 2 TESS sectors (13 and 27).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up has made several detections of the transit of TOI-1075.01 on TIC 351601843 (shown in Figure 4).

The DAVE analysis of this TOI found no strong indicators that the candidate is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (1.01 ± 0.16) × 10⁻³. Because TIC 351601843 has been verified as the host of the transit, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-1075 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={4.3}_{-1.5}^{+2.9}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={4.0}_{-1.4}^{+2.7}\,{M}_{\oplus }$.

TOI-1242.01 is a 1.65 ± 0.23 R_⊕ planet candidate with a 0.38 day orbital period orbiting a K dwarf (TIC 198212955) that is 110 pc away and has a V magnitude of 12.78. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.03, indicating that the star is quiet. This is corroborated by the low $v\sin i$ extracted from our TRES spectrum. TOI-1242 has been observed in 15 TESS sectors (14–26, 40, and 41) and is scheduled to be reobserved in another 8 sectors (48–55) between 2022 January 28 and 2022 September 1.

High-resolution imaging of this star detects TIC 198212956, a previously known star that is 43 north and 2.6 mag fainter in the TESS band but finds no other unresolved stars within detection limits. TIC 198212956 is almost certainly bound to TIC 198212955, due to their similar parallaxes and proper motions as reported by Gaia DR2. Spectroscopic observations confirm that the star is on the main sequence and rule out obvious spectroscopic binaries. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit except for TIC 198212956. The 0.6 ppt event seen in the TESS data has not been detected around the target star or its companion.

The DAVE analysis of this TOI detects a potential centroid offset to the northeast but finds no other indicators that this TOI is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (3.36 ± 0.17) × 10⁻² and NFPP = (2.92 ± 0.16) × 10⁻². These >1% FPP and NFPP are driven by the uncertainty over whether or not the transit originates from the target star or TIC 198212956. This FPP and NFPP are too high to consider this planet candidate validated.

Assuming this is a real planet around TIC 198212955, we estimate the semiamplitude of the RV signal to be ${K}_{\mathrm{RV}}={3.7}_{-1.7}^{+3.0}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={3.7}_{-1.5}^{+2.9}\,{M}_{\oplus }$.

TOI-1263.01 is a 1.36 ± 0.16 R_⊕ planet candidate with a 1.02 day orbital period orbiting a K dwarf (TIC 406672232) that is 46.6 pc away and has a V magnitude of 9.36. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.12, indicating that the star is quiet. This is corroborated by the low $v\sin i$ extracted from our TRES and FIES spectra. TOI-1263 has been observed in three TESS sectors (14, 15, and 41) and is scheduled to be reobserved in another sector (55) between 2022 August 5 and 2022 September 1.

High-resolution imaging of this star detects TIC 1943945558, a previously known star that is 26 southeast and 3.6 mag fainter in the TESS band, but finds no other unresolved stars within detection limits. TIC 1943945558 is almost certainly bound to TIC 406672232 due to their similar parallaxes and proper motions as reported by Gaia DR2. Multiple spectroscopic observations confirm that the star is on the main sequence and rule out obvious spectroscopic binaries. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit except for TIC 1943945558 and TIC 1943945562, which is 91 northeast and 7.4 mag fainter in the TESS band. The 0.26 ppt event seen in the TESS data has not been detected around the target star.

The DAVE analysis of this TOI detects a potential difference between the even and odd primary transits, which could be indicative of an FP in the form of an eclipsing binary. DAVE did not report any other FP indicators for this TOI. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (1.12 ± 0.05) × 10⁻² and NFPP = (1.04 ± 0.05) × 10⁻². These >1% FPP and NFPP are driven by the uncertainty over whether or not the transit originates from the target star or TIC 1943945562. This FPP and NFPP are too high to consider this planet candidate validated.

Assuming this is a real planet around TIC 406672232, we estimate the semiamplitude of the RV signal to be ${K}_{\mathrm{RV}}={1.8}_{-0.7}^{+1.3}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.4}_{-0.8}^{+1.7}\,{M}_{\oplus }$.

TOI-1411.01 is a 1.36 ± 0.16 R_⊕ planet candidate with a 1.45 day orbital period orbiting a K dwarf (TIC 116483514) that is 32.5 pc away and has a V magnitude of 10.51. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.02, indicating that the star is quiet. This is corroborated by the $\mathrm{log}{R}_{{\rm{H}}\ {\rm{K}}}^{{\prime} }$ of −4.7252 extracted from our HIRES spectrum and the low $v\sin i$ extracted from our TRES spectrum. TOI-1411 has been observed in three TESS sectors (16, 23, and 24) and is scheduled to be reobserved in another two sectors (50 and 51) between 2022 March 26 and 2022 May 18.

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit. Of note to this TOI is TIC 1101969798, a periodic variable with a semiamplitude of 0.1 mag and a period of 0.107 days, which is located 90'' to the northeast.

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (1.18 ± 0.68) × 10⁻⁴. Because all neighboring stars have been cleared, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-1411 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={2.0}_{-1.0}^{+1.7}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.5}_{-1.1}^{+2.0}\,{M}_{\oplus }$. D. Vermilion et al. (2021, in preparation), who detect the RV signal of this planet, reports a K_RV 5σ upper limit of 4.26 m s⁻¹ (or a mass of 5.66 M_⊕), consistent with our estimate and with a terrestrial composition.

TOI-1442.01 is a 1.17 ± 0.06 R_⊕ planet candidate with a 0.41 day orbital period orbiting an M dwarf (TIC 235683377) that is 41.2 pc away and has a V magnitude of 15.39. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.02, indicating that the star is quiet. TOI-1442 has been observed in 15 TESS sectors (14–26, 40, and 41) and is scheduled to be reobserved in another 9 sectors (47–55) between 2021 December 30 and 2022 September 1.

Follow-up observations have found no evidence of this TOI being an FP, although no spectroscopic observations of this TOI have been collected. Time-series photometric follow-up has made several detections of the transit of TOI-1442.01 on TIC 235683377 (shown in Figure 5).

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. However, the S/N of the per-transit difference images used by DAVE is very low, and the measured centroids are unreliable. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (7.00 ± 4.11) × 10⁻⁶. Because the transit has been verified on target, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-1442 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.2}_{-1.0}^{+2.2}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={1.6}_{-0.5}^{+1.1}\,{M}_{\oplus }$.

TOI-1693.01 is a 1.42 ± 0.10 R_⊕ planet candidate with a 1.77 day orbital period orbiting an M dwarf (TIC 353475866) that is 30.8 pc away and has a V magnitude of 12.96. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.01, indicating that the star is quiet. This is corroborated by the $\mathrm{log}{R}_{{\rm{H}}\ {\rm{K}}}^{{\prime} }$ of –5.2169 extracted from our HIRES spectrum. TOI-1693 has been observed in four TESS sectors (19 and 43–45).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up has made several detections of the transit of TOI-1693.01 on TIC 353475866 (shown in Figure 6). ⁸⁷

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI finds FPP = (1.47 ± 0.13) × 10⁻³. Because the transit has been verified on target, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-1693 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={2.4}_{-0.8}^{+1.9}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.8}_{-1.0}^{+2.2}\,{M}_{\oplus }$.

TOI-1860.01 is a 1.31 ± 0.04 R_⊕ planet candidate with a 1.07 day orbital period orbiting a G dwarf (TIC 202426247) that is 45.9 pc away and has a V magnitude of 8.4. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.83, indicating strong activity and a young host star. We also estimate a $\mathrm{log}{R}_{{\rm{H}}\ {\rm{K}}}^{{\prime} }$ of –4.2524 from our HIRES spectrum, which indicates that the star is young and active. TOI-1860 has been observed in seven TESS sectors (14–16, 21–23, and 41) and is scheduled to be reobserved in another three sectors (48–50) between 2022 January 28 and 2022 April 22.

Because this is an active star, we can use the TESS light curve to derive its rotation period. In Figure 7, we display the results of a Lomb–Scargle periodogram applied to each sector separately, which gives a rotation period of 4.43 ± 0.06 days. Using the relation defined in Barnes (2007), we estimate the age of the star to be 133 ± 26 Myr. Lastly, we use BANYAN Σ (Gagné et al. 2018) to determine the probability that the star is a member of a nearby young association. This analysis returns a 99.9% probability that TOI-1860 is a field star.

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Another interesting aspect of TOI-1860 is that it has stellar parameters and a metallicity very similar to that of the Sun and qualifies as a solar twin according to most definitions (de Strobel 1996; Ramírez et al. 2014). For solar twins, there is known to be a strong correlation between [Y/Mg] and stellar age (Nissen 2015; Maia et al. 2016). Because we obtained elemental abundances for this star using KeckSpec (see Table 6), we are able to conduct an independent check of the age of this system. Using the relation provided in Maia et al. (2016) and [Y/Mg] = 0.196 ± 0.090, we estimate an age upper limit of 1.93 Gyr, which is consistent with our estimation based on gyrochronology.

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit except for TIC 1102367690, which is 55 west and 5.8 mag fainter in the TESS band. The 0.23 ppt event seen in the TESS data has not been detected around the target star.

DAVE was unable to perform a vetting analysis of this TOI, due to a failure of its transit model to fit the TESS data. The SPOC data validation report for this TOI reports no significant centroid offset.

The TRICERATOPS analysis of this TOI find FPP = (1.97 ± 0.45) × 10⁻⁴ and NFPP = (9.68 ± 2.23) × 10⁻⁶. This FPP and NFPP are sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-1860 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={1.4}_{-0.4}^{+0.8}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.2}_{-0.7}^{+1.3}\,{M}_{\oplus }$.

TOI-2260.01 is a 1.62 ± 0.13 R_⊕ planet candidate with a 0.35 day orbital period orbiting a G dwarf (TIC 232568235) that is 101.3 pc away and has a V magnitude of 10.47. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.93, indicating strong activity and a young host star. We also estimate a $\mathrm{log}{R}_{{\rm{H}}\ {\rm{K}}}^{{\prime} }$ of –4.438 from our HIRES spectrum, which indicates that the star is young and active. TOI-2260 has been observed in three TESS sectors (23–25) and is scheduled to be reobserved in another three sectors (50–52) between 2022 March 26 and 2022 June 13.

Because this is an active star, we can use the TESS light curve to derive its rotation period. In Figure 7, we display the results of a Lomb–Scargle periodogram applied to each sector separately, which gives a rotation period of 8.45 ± 0.03 days. Using the relation defined in Barnes (2007), we estimate the age of the star to be 321 ± 96 Myr. Lastly, we use BANYAN Σ (Gagné et al. 2018) to determine the probability that the star is a member of a nearby young association. This analysis returns a 99.9% probability that TOI-2260 is a field star.

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit.

The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. The SPOC data validation report for this TOI reports a significant centroid offset in sector 24 but has not conducted centroid offset analyses for sectors 23 and 25. However, given that all neighboring stars have been cleared from being nearby eclipsing binaries, this offset is unlikely to be caused by an FP coming from a nearby star.

The TRICERATOPS analysis of this TOI finds FPP = (5.26 ± 0.50) × 10⁻³. Because all neighboring stars have been cleared, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-2260 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.0}_{-1.1}^{+2.2}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={3.5}_{-1.3}^{+2.5}\,{M}_{\oplus }$.

TOI-2290.01 is a 1.17 ± 0.07 R_⊕ planet candidate with a 0.39 day orbital period orbiting a K dwarf (TIC 321688498) that is 58.1 pc away and has a V magnitude of 12.64. A Lomb–Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.03, indicating that the star is quiet. However, the $\mathrm{log}{R}_{{\rm{H}}\ {\rm{K}}}^{{\prime} }$ of −4.459 extracted from our HIRES spectrum suggests that the star may actually be quite active. TOI-2290 has been observed in four TESS sectors (17, 18, 24, and 25).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up of this TOI has cleared all neighboring stars as origins of the transit.

The DAVE analysis of this TOI finds a potential centroid offset but finds no other significant FP indicators. No data validation reports have been generated by the SPOC pipeline for this TOI.

The TRICERATOPS analysis of this TOI finds FPP = (4.92 ± 0.11) × 10⁻¹. Because all neighboring stars have been cleared, TRICERATOPS finds NFPP = 0.0. The reason for this >1% FPP comes from the scenario that the TOI is a blended eclipsing binary. This FPP is too high to consider the planet validated.

Assuming this is a real planet, we estimate the semiamplitude of the RV signal to be ${K}_{\mathrm{RV}}={2.1}_{-0.7}^{+1.7}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={1.6}_{-0.6}^{+1.4}\,{M}_{\oplus }$.

TOI-2411.01 is a 1.68 ± 0.11 R_⊕ planet candidate with a 0.78 day orbital period orbiting a K dwarf (TIC 10837041) that is 59.5 pc away and has a V magnitude of 11.27. A Lomb−Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.002, indicating that the star is quiet. TOI-2411 has been observed in two TESS sectors (3 and 30).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up has made several detections of the transit of TOI-2411.01 on TIC 10837041 (shown in Figure 8).

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DAVE is unable to analyze this TOI due to the very low S/N of the data. The SPOC data validation report for this TOI reports no significant centroid offset or any other FP indicators.

The TRICERATOPS analysis of this TOI finds FPP = (1.17 ± 0.05) × 10⁻³. Because transits have been verified on target, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet as TOI-2411 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.6}_{-1.3}^{+2.5}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={3.9}_{-1.4}^{+2.8}\,{M}_{\oplus }$.

TOI-2427.01 is a 1.80 ± 0.12 R_⊕ planet candidate with a 1.31 day orbital period orbiting a K dwarf (TIC 142937186) that is 28.5 pc away and has a V magnitude of 10.30. A Lomb−Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.05, indicating that the star is quiet. TOI-2427 has been observed in one TESS sector (31).

Follow-up observations have found no evidence of this TOI being an FP. Time-series photometric follow-up has made several detections of the transit of TOI-2427.01 on TIC 142937186 (shown in Figure 9).

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The DAVE analysis of this TOI finds a potential centroid offset but finds no other indicators that this TOI is an FP. The SPOC data validation report for this TOI also reports a significant centroid offset. However, given that all neighboring stars have been cleared from being nearby eclipsing binaries, this offset is unlikely to be caused by an FP originating from a nearby star.

The TRICERATOPS analysis of this TOI finds FPP = (7.35 ± 2.72) × 10⁻³. Because transits have been verified on target, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereafter refer to this planet TOI-2427 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={3.2}_{-1.2}^{+2.4}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={4.1}_{-1.5}^{+3.1}\,{M}_{\oplus }$.

TOI-2445.01 is a 1.25 ± 0.08 R_⊕ planet candidate with a 0.37 day orbital period orbiting an M dwarf (TIC 439867639) that is 48.6 pc away and has a V magnitude of 15.69. A Lomb−Scargle periodogram of the photometry from each TESS sector finds a maximum peak of 0.04, indicating that the star is quiet. TOI-2445 has been observed in two TESS sectors (4 and 31).

Follow-up observations have found no evidence of this TOI being an FP, although no spectroscopic observations of this TOI have been collected. Time-series photometric follow-up has made several detections of the transit of TOI-2445.01 on TIC 439867639 (shown in Figure 10).

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The DAVE analysis of this TOI finds no strong indicators that the candidate is an FP. However, like TOI-739, the S/N of the per-transit difference images used by DAVE is very low and the measured centroids are unreliable. No data validation reports have been generated by the SPOC pipeline for this TOI.

The TRICERATOPS analysis of this TOI finds FPP = (1.88 ± 0.45) × 10⁻⁴. Because transits have been verified on target, TRICERATOPS finds NFPP = 0.0. This FPP is sufficiently low to consider the planet validated. We hereby refer to this planet as TOI-2445 b.

We estimate the semiamplitude of the RV signal for this planet to be ${K}_{\mathrm{RV}}={4.5}_{-1.7}^{+2.8}$ m s⁻¹, corresponding to ${M}_{{\rm{p}}}={2.0}_{-0.7}^{+1.2}\,{M}_{\oplus }$.