Protostars and Planets VI, Heidelberg, July 15-20, 2013

Poster 1K085

Orbits and Masses in the young triple system TWA 5

Köhler, Rainer (MPI für Astronomie)
Ratzka, Thorsten (Universitäts-Sternwarte München)
Petr-Gotzens, Monika (ESO Garching)

TWA5 is one of the 5 original members of the TW Hydrae association. It is composed of three components: a pair of low-mass stars, TWA 5Aa-b, and a brown dwarf companion, TWA 5B. TWA 5Aa-b had a separation of 55mas when it was discovered in 2000, while TWA 5B is located about 2arcsec away. We obtained new relative astrometric measurements of all three components with NACO at the VLT. We use these observations and data from the literature to derive an improved fit for the orbit of TWA 5Aa/Ab around each other. Furthermore, we use TWA 5B as astrometric reference to solve for the individual orbits of Aa and Ab. This allows us to estimate the mass ratio of Aa and Ab, and hence individual masses of the two components. We compare the resulting masses to masses predicted by theoretical evolutionary tracks.

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