EPoS Contribution
EPoS Contribution
The VLA/ALMA Nascent Disk and Multiplicity Survey of Perseus and Orion

John Tobin
OU, Norman, US
The formation of multiple star systems and disks is likely to begin early in the star formation process. Large, unbiased samples must be observed in order to fully understand what physics govern the formation of multiple systems, rotationally-supported disks, and when they arise. Results from the VLA Nascent Disk and Multiplicity Survey (VANDAM) for a sample of ~80 protostars in Perseus revealed evidence for a bi-modal distribution of companion protostar separations. The peaks of the distribution at ~75 AU and 3000 AU, may be evidence for disk fragmentation on small scales and turbulent fragmentation on large-scales. Furthermore, we detected evidence for disks with radii >20 AU toward 18 Class 0/I systems (including apparent circumbinary disks). Building on these results, we have embarked on the VANDAM II survey toward 330 protostars in the Orion molecular clouds at 30 AU resolution using ALMA at 850 micron and the VLA for a subset at 9 mm and 30 AU resolution (148 sources; ~100 Class 0s). This new Orion survey has greater sensitivity to extended disks because of the shorter wavelength where dust emission is brighter (850 micron) and has 4x more sources to substantially improve the characterization of the multiplicity frequency. We will present highlights and initial results from the ALMA and VLA Orion survey on multiplicity and the frequency of resolved disks (and other structures) at both 850 micron and 9 mm. The results presented demonstrate the power and utility of unbiased surveys of protostars and fully leverage the complementary power of both the VLA and ALMA.
Caption: A gallery of Class 0 disks for a wide range of luminosities toward Class 0 protostars in Orion.
Collaborators:
S.T. Megeath, U Toledo, US
N. Karnath, U Toledo, US
P. Sheehan, OU, US
L. Looney, UIUC, US
C. Chandler, NRAO, US
Z.Y. Li, U Virginia, US
D. Segura-Cox, MPE, DE
VANDAM Team
Key publication

Suggested Session: Protostellar disks