EPoS Contribution
EPoS Contribution
High angular resolution radio-astrometry to YSOs in the ONC core

Sergio Dzib
MPIfR, Bonn, DE
In the last few years, we have observed compact radio sources associated to YSOs in the ONC core to determine their astrometric parameters. VLA observations spanned in a time period of 30 years were used to study the proper motions of ~100 YSOs and study the kinematic properties of the cluster. On the other hand, as part of the Gould Belt Distances survey (GOBELINS), VLBA observations to the more compact radio sources were used to accurately determine their distances and to obtain a better determina- tion of the mean distance to the ONC. With the recent second Data release of the Gaia mission (Gaia DR2) our findings are being confirmed and probe that the VLBA astrometric results are highly accurate. Thus, we are now observing a larger sample of YSOs (556) with the VLBA with the objective to nail down the non-thermal population, to study the kinematics of the cluster, and to look for tight binaries (separations < 0.1 arcseconds) to estimate their dynamical masses. In this talk, I will present the new results from these observations and how they compare with Gaia DR2 results.
Caption: Absolute proper motions of radio stellar sources using VLA observations.
Collaborators:
J. Forbrich, UH, UK
J. Vargas, UH, UK
G. Ortiz-Leon, MPIfR, DE
L. Loinard, IRyA-UNAM, MX
Key publication

Suggested Session: High-Mass Star Formation