Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars

Details Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars

Jul 2007

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007a%26a...469..285v&link_type=abstract

Astronomy and Astrophysics, Volume 469, Issue 1, July I 2007, pp.285-296

Astronomy and Astrophysics

Astrophysics

14

Stars: Binaries: Eclipsing, Stars: Fundamental, Parameters, Stars: Evolution, Galaxy: Evolution

Scientific paper

Context: Precise stellar masses and radii provide unique information on stellar evolution. In a Galactic context, they may also provide information on the evolution of the Solar neighbourhood. Aims: We aim to determine absolute dimensions for the mid B-type eclipsing binary U Ophiuchi and compare the inferred ages and chemical compositions to those of other binary stars with masses near 5 {M}&sun;. Methods: We determine masses, radii, log g, log T_eff, and luminosities for the stars in U Oph from new radial velocities and uvby light curves. By improving the Wilson-Devinney code, we also derive precise apsidal-motion and light-time orbits of this triple system, using 353 times of minimum over 120 years. Finally, we compare the data for U Oph and three similar systems with the predictions of stellar models. Results: The stars in U Oph have masses of 5.27 ± 0.09 {M}&sun; and 4.74 ± 0.07 {M}&sun;, radii of 3.48 ± 0.02 {R}&sun; and 3.11 ± 0.03 {R}&sun;; we argue that systematic errors are negligible. The apsidal motion period is exceptionally short, U ˜21 yr, while the light-time orbit has P3 ˜ 38.4 yr. The precise log g values for DI Her, U Oph, V760 Sco, and MU Cas, all within 10% of 5 {M}&sun;, place them successively from the ZAMS to the TAMS, at ages of 5-100×106 yr. Current stellar evolution models fit both stars in each system very well if the (otherwise unconstrained) metal abundance Z is adjusted in each case. Conclusions: More accurate data and/or binary systems with larger mass ratios are needed to actually test stellar models near 5 {M}&sun;. The different Z values found for these young, nearby systems suggest that disk stars form with a range of metal abundances even today, but more data are needed to confirm this result.
Based on observations collected at the European Southern Observatory, La Silla, Chile. Table [see full text] is only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/469/285

Affiliated with

Also associated with

No associations

Rating

Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absolute dimensions of eclipsing binaries. XXV. U Ophiuchi and the evolution and composition of 5 M&sun; stars will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1027929