Research Note

What are the temperatures of T Tauri stars?

Constraints from coeval formation of young eclipsing binaries

¹ AIU Jena, Schillergäßchen 2-3, 07745 Jena, Germany e-mail: ammler@astro.uni-jena.de
² Sterrewacht Leiden/ Leiden Observatory, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands

Received: 5 January 2005
Accepted: 24 June 2005

Abstract

We show how the assumption of coeval formation can be used to constrain the effective temperatures of the components of young eclipsing double-lined spectroscopic binaries. Our method extends the approach of White et al. (1999) to a two-step analysis. The first step compares evolutionary models to the observed masses and radii and selects those models that predict ages that are consistent with coeval formation. The second step then uses these models to constrain the effective temperatures. We applied the method to literature values of the stellar parameters of the eclipsing binaries RX J0529.4+0041 A and V1174 Ori and confirm that V1174 Ori A has dwarf-like temperatures at an age of 9 Myrs, while we cannot draw any conclusions for RX J0529.4+0041 A and V1174 Ori B. Considering these binaries, we find that none of the evolutionary models gives coeval solutions simultaneously in mass, radius and effective temperature.