EPoS Contribution
EPoS Contribution
New Constraints on Protostellar Multiplicity and Disk Formation

Michael Dunham
CfA-SAO, Cambridge, US
The transfer of mass from cores to stars is regulated by the complex interaction of many physical properties, including gravity, turbulence, conservation of angular momentum, and magnetic fields. The formation of both disks and multiple systems can give important clues to the relative roles these processes play in star formation, and furthermore both have profound effects on the efficiency with which the mass in cores collapses to form stars. While both disks and multiple systems are generally thought to begin early in the star formation process, current observations lack the resolution, sensitivity, and statistics to determine when and where most binaries form and whether or not large, massive disks are common at early times. On behalf of a large collaboration, I will present initial results from a large, 264 hour Jansky VLA program (PI: John Tobin) to observe all 80 protostars in the Perseus Molecular Cloud in the B and A configurations at 8 mm and 1, 4, and 6 cm. This program is sensitive to both dust and free-free emission, and will obtain a final spatial resolution of 15 AU, capable of detecting very close binaries and sampling the peak of the field binary separation distribution (~50 AU) toward protostars for the very first time. We will also detect and resolve disks as small as 30 AU. We currently have all data from the B array and are already detecting numerous multiple systems with separations less than 100 AU, and all remaining data will be taken by the time of the conference. This is the largest and most complete high-resolution millimeter/centimeter wavelength survey of protostellar binaries and disks to date and will greatly improve our understanding of the earliest stages of star formation.
Caption: VLA 8 mm observations of sixteen binary sources detected in our B-configuration data obtained to date, with each panel 4" on a side. All binary detections are greater than 7sigma, are detected at both 8 mm and 1 cm, and have projected separations ranging from 60 to 420 AU.
Collaborators:
J. Tobin, NRAO, USA
L. Looney, UIUC, USA
Z.-Y. Li, UVa, USA
C. Chandler, NRAO, USA
K. Kratter, JILA, USA
S. Sadavoy, MPIA, Germany
L. Perez, NRAO, USA
D. Segura-Cox, UIUC, USA
C. Melis, UCSD, USA
R. Harries, UIUC, USA
Suggested Session: Cores to Disks