1. The Eclipsing Triple System U Ophiuchi Revisited – poster 094 Symposium 240 BINARY STARS AS CRITICAL TOOLS AND TESTS IN CONTEMPORARY ASTROPHYSICS Luiz Paulo R. Vaz – UFMG - Brazil Johannes Andersen – Copenhagen University - Denmark Antônio Claret – IAA – Spain

2. U Ophiuchi - Motivation  Mid B-type (~5Msun) on the Main Sequence  Eclipsing system (P ~ 1.67 d)  Triple system (P3 ~ 38.4 yr)  Apsidal motion (U ~ 21.2 yr)  Opportunity to improve absolute dimensions determination and to test evolutionary models

3. Spectroscopic analysis  Photographic spectra from ESO 1.5m  Primary with stronger and broader lines  New ephemeris (including apsidal motion and light- time orbit) fully accounted for in the analysis

4. Photometric analysis  uvbyHβ SAT observations  HR6412 detected as eclipsing  Wilson-Devinney simultaneous solutions: 4 LCs (uvby) + 2 RVs (pri/sec) and fully account for the ephemeris  Both traditional least-squares and SIMPLEX minimization methods

5. Apsidal Motion and light-time orbit  Lacy (1992) exact method for apsidal motion, implemented with time-light effect Irwin 1952, 1959  353 times of minima (229 pri, 124 sec) carefully selected from 512 (334 pri, 178 sec) individual times from literature from 1882 to 2004

6. New ephemeris  Radial velocity and light curves taken at different dates (and orbital configurations) analized simultaneously

7. Absolute Dimensions

8. Evolutionary status and comparison with other systems  U Oph is well fitted with Z=0.02, Y=0.28  MU Cas and V760 Sco seem to require Z=0.01  Difficult to assign ages with models, coevality is the key  DI Her is still a puzzle (too young, too long apsidal motion period)

9. Conclusions  Claret and Padova models give different ages, but are consistent with respect to coevality  The chemical diversity of these young systems (all younger than 100Myr old) presents a challenge to models of galactic chemical evolution