Orbital constraints and mass determination of a young binary system Maria-Jose Maureira MPE, Garching, DE
The most widely used method to estimate protostellar masses uses the Keplerian rotation of the gas in the disk around the protostar, performed only in a few and mostly isolated objects in the earliest stages. However, since rotation and infall coexist, gas motions can deviate from a standard Keplerian profile, and hence measured masses may not reflect true protostellar masses. Constraining orbital parameters in multiple systems is the only direct method to measure protostellar masses, and thus embedded multiple systems are the best laboratory to weight stars during the assembly stages. I will present ALMA 3 mm observations at a resolution of ~7 au that confirm one of the most well-studied protostellar system (IRAS 16293-2422 A) as a very young binary (IRAS 16293 A1 and A2), currently separated by 54 au. By combining the new ALMA positions and radial velocity measurement with previous VLA radio astrometric observations we constrain the relative orbital parameters, yielding a direct measurement of the protostellar mass. This is the most embedded multiple system for which protostellar masses are robustly determined by orbital motions, providing the best laboratory to measure masses at the earliest stages.
Collaborators: J. E. Pineda, MPE, DE D. Segura-Cox, MPE, DE P. Caselli, MPE, DE L. Testi, ESO, DE G. Lodato, UNIMI, IT L. Loinard, UNAM, MX A. Hernandez-Gomez, MPIR, DE	Suggested Session: Cores2Disks