We present ALMA 850 µm continuum observations of the Orion Nebula Cluster that provide the highest angular resolution (∼ 0.001 ≈ 40 AU) and deepest sensitivity (∼ 0.1 mJy) of the region to date. We mosaicked a field containing ∼ 225 optical or near-IR-identified young stars, ∼ 60 of which are also optically-identified “proplyds”. We detect continuum emission at 850 µm towards ∼ 80% of the proplyd sample, and ∼ 50% of the larger sample of previously-identified cluster members. Detected objects have fluxes of ∼ 0.5–80 mJy. We remove sub-mm flux due to free-free emission in some objects, leaving a sample of sources detected in dust emission. Under standard assumptions of isothermal, optically thin disks, sub-mm fluxes correspond to dust masses of ∼ 0.5 to 80 Earth masses. We measure the distribution of disk sizes, and find that disks in this region are particularly compact. Such compact disks are likely to be significantly optically thick. The distributions of sub-mm flux and inferred disk size indicate smaller, lower-flux disks than in lower-density star-forming regions of similar age. Measured disk flux is correlated weakly with stellar mass, contrary to studies in other star forming regions that found steeper correlations. We find a correlation between disk flux and distance from the massive star θ1 Ori C, suggesting that disk properties in this region are influenced strongly by the rich cluster environment.
|Original language||English (US)|
|State||Published - May 9 2018|
- Galaxy:Open Clusters and Associations:Individual: Orion
- Stars: Pre-Main-Sequence
- Stars:Planetary Systems:Protoplanetary Disks
ASJC Scopus subject areas