ALMA Observations of the Orion Proplyds


Using the Atacama Large Millimeter/Submillimeter Array (ALMA), we surveyed 22 Hubble Space Telescope identified protoplanetary disks in Orion.  We detected 21 of these disks using ALMA at 850 um and determined their disk masses.  Nine disks were detected for the first time, including prominent and puzzling disk 114-426 (see below).  The disk masses ranged from 0.3-80 Jupiter masses, with ~10% of the disks having sufficient mass to potentially form a Solar system like ours.   These results will be published in the March 20th edition of Astrophysical Journal, ApJ, 2014, 784, 82;  See Press Release; Full Paper; Quirks & Quarks Interview

Collaborators: James Di Francesco, Sean M. Andrews, Jonathan P. Williams, Doug Johnstone,            John Bally, Luca Ricci, A. Meredith Hughes, Brenda C. Matthews.

Mann et al. 2014, ApJ

Mann et al. 2014, ApJ

The ALMA images are the highest resolution observations ever taken at submillimeter wavelengths towards the Orion Nebula, comparable to the Hubble Space Telescope images.

Combining our new Atacama Large Millimeter/Submillimeter Array observations with previous Submillimeter Array observations of the Orion disks, we find a clear correlation between disk mass and distance from the massive O-star, θ1 Ori C.  Particularly at short distances from θ1 Ori C, within 0.03pc (0.1 lightyears) of the O-star, we find there is a lack of disks with masses appropriate to reproduce our Solar system.  At larger separations from the massive star, there is a wide range of disk masses, similar to that found in low mass star forming regions like Taurus, with at least 10% of the stars having appropriate masses to potentially form Solar systems like our own.  These results suggest that a rapid dissipation of disk masses likely inhibits potential planet formation in the extreme-UV dominated regions of OB associations, but leaves disks in the far-UV dominated regions relatively unaffected.

We also have an approved Cycle 1 project using the Atacama Large Millimeter Array to study protoplanetary disks in the Orion Nebula. These observations will exploit ALMA’s Early Science capabilities to perform the most sensitive and large-scale study of protoplanetary disks in Orion at submillimeter wavelengths, surveying 300 young stars, including ~75% of all known Hubble Space Telescope identified disks in the region.