EPoS Contribution
EPoS Contribution
Dynamical Masses of young visual binaries

Rainer Koehler
NN, Heidelberg, DE
The mass is the most important parameter for the structure and evolution of a star. Therefore, empirical mass determinations are crucial for our understanding of stellar astrophysics. In particular, this is the case for low-mass pre-main-sequence stars, for which a number of evolutionary models with different mass predictions exist. The stellar masses and ages derived from these models form the basis for studies of, e.g., the Initial Mass Function, cluster ages, and disk lifetimes. It is therefore important to calibrate pre-main- sequence tracks with model-independent mass measurements. The only way to do this is with the help of dynamics, namely by determining the orbits of binary stars. We are monitoring a number of young visual binaries that were discovered in the 1990s. Many of them show significant orbital motion by now, and it was possible to determine the orbit for some. We will present first results and show some interesting systems.
Caption: The dynamical mass of TWA 5Aa-Ab compared to predictions by pre-main-sequence models.
Collaborators:
T. Ratzka, PiMaS, DE
R. Grellmann, U Cologne, DE
K. Kubiak, U Lisbon, PT
Suggested Session: Galactic Dynamics