Quick search Find article
Quick search
Find article

Distribution of Circumstellar Disk Masses in the Young Cluster NGC 2024

FREE

J. A. Eisner1 and John M. Carpenter1

Show affiliations


We determine the distribution of circumstellar disk masses in the young (~0.3 Myr) cluster NGC 2024 by imaging a 2farcm5 × 2farcm5 region in 3 mm continuum emission to an rms noise level of ~0.75 mJy beam-1 with the Owens Valley Millimeter Array. The mosaic encompasses 147 K-band sources, as well as the molecular ridge seen previously in dust continuum emission. We detect 10 pointlike sources in 3 mm continuum emission above the level of 5 σ within the unit gain region of the mosaic. One of these sources corresponds to the near-IR source IRS 2, an early B-type star. Two other sources are tentatively associated with low-mass near-IR cluster members, and the remaining seven sources have no K-band counterparts. Assuming the millimeter continuum point sources represent emission from circumstellar disks and/or envelopes, then ~6% of the total population (infrared and millimeter sources) in the NGC 2024 mosaic have a circumstellar mass in excess of ~0.06 Msun. We obtain further constraints on the average circumstellar disk mass by considering the mean millimeter continuum flux observed toward a sample of 140 K-band sources that likely have stellar masses lesssim1-2 Msun. While none of these sources are detected individually above the 3 σ limit of ~0.035 Msun, the ensemble of sources are detected in the mean at the 5 σ level with a mean disk mass of ~0.005 Msun. Compared with the older (~2 Myr) cluster IC 348, NGC 2024 contains a higher frequency of massive disks or envelopes and has a higher mean disk mass by a factor of 2.5 ± 1.3 among K-band sources, suggesting that the mean circumstellar mass is decreasing with cluster age. We also compare the results for the NGC 2024 and IC 348 clusters with those for the lower density Taurus star-forming region. Finally, we compare our detection limits with the minimum mass estimate for the proto-solar nebula and discuss possible implications for planet formation.


Subject headings

open clusters and associations: individual (NGC 2024); planetary systems: protoplanetary disks; stars: pre-main sequence


Dates

Issue 2 (2003 December 1)

Received 2003 June 4, accepted for publication 2003 August 15



Users also read

What's this?
This innovative new feature generates a list of articles 'also read' by other users based on them reading the original article. Article abstracts citations and references are all considered and weighted accordingly. We hope that this will help you find relevant papers for your research.

  1. Proplyds and Massive Disks in the Orion Nebula Cluster Imaged with CARMA and SMA

View by subject




Export








Please login to access our web services, or create an account if you don't yet have one.

You must have cookies enabled in your web browser to be able to login.

Username
Password

Forgotten your password? Get a new one here.