Astronomy and Astrophysics – Astrophysics – Solar and Stellar Astrophysics
Scientific paper
2009-10-23
Astronomy and Astrophysics
Astrophysics
Solar and Stellar Astrophysics
14 pages, 13 figures. Accepted for publication in ApJ
Scientific paper
We report extensive spectroscopic and differential photometric BVRI observations of the active, detached, 1.309-day double-lined eclipsing binary IM Vir, composed of a G7-type primary and a K7 secondary. With these observations we derive accurate absolute masses and radii of M(1) = 0.981 +/- 0.012 M(Sun), M(2) = 0.6644 +/- 0.0048 M(Sun), R(1) = 1.061 +/- 0.016 R(Sun), and R(2) = 0.681 +/- 0.013 R(Sun) for the primary and secondary, with relative errors under 2%. The effective temperatures are 5570 +/- 100 K and 4250 +/- 130 K. The significant difference in mass makes this a favorable case for comparison with stellar evolution theory. We find that both stars are larger than the models predict, by 3.7% for the primary and 7.5% for the secondary, as well as cooler than expected, by 100 K and 150 K, respectively. These discrepancies are in line with previously reported differences in low-mass stars, and are believed to be caused by chromospheric activity, which is not accounted for in current models. The effect is not confined to low-mass stars: the rapidly-rotating primary of IM Vir joins the growing list of objects of near-solar mass (but still with convective envelopes) that show similar anomalies. The comparison with the models suggests an age of 2.4 Gyr for the system, and a metallicity [Fe/H] of approximately -0.3 that is consistent with other indications, but requires confirmation.
Brehm W.
Marschall Laurence A.
Morales Juan Carlos
Torres Gabino
No associations
LandOfFree
Absolute dimensions of the G7+K7 eclipsing binary star IM Virginis: Discrepancies with stellar evolution models 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 the G7+K7 eclipsing binary star IM Virginis: Discrepancies with stellar evolution models, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Absolute dimensions of the G7+K7 eclipsing binary star IM Virginis: Discrepancies with stellar evolution models will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-423378