Astron. Astrophys. 319, 535-546 (1997)

6. Summary

In this paper we presented the first Doppler images of IN Virginis, a moderately rapid rotating K2-3 subgiant in a spectroscopic binary system. Our main results can be summarized as follows:

1. IN Virginis is shown to be a single-lined spectroscopic binary with an orbital period of 8.1985 0.0009 days. Our new photometric period of 8.232 0.003 days indicates a synchronized rotator with respect to the orbital motion.
2. Several observational criteria agree best with a K2-3 spectral type and a subgiant luminosity classification.
3. The relatively small equatorial rotational velocity of 28 km s^-1 ( =24.0 km s^-1, ) is obviously sufficient for a K2-3 star to produce very strong chromospheric radiative losses.
4. From a spectrum synthesis we found an overabundance of heavy elements compared to the Sun (e.g. 0.05 dex for iron) but roughly solar abundance for some lighter elements. The low-to-moderate (logarithmic) lithium abundance of 0.55 is typical for evolved RS CVn stars.
5. The overall surface temperature and their respective rotationally modulated variation in 1994 were determined from three different techniques and yielded consistent results of 1000 K for the coolest, and thus dominating, features.
6. The morphology of the Doppler map of IN Vir is very similar to its "cousin" HU Virginis (K0IV, days) and is dominated by a cool polar spot with two appendages, a larger and a smaller one. Additionally, three equatorial spots with an average temperature difference of 400 K are seen. A warm equatorial spot with -150 K has been also recovered from all mapping lines and is likely real.
7. From three Ca II H&K spectra taken in 1995 and in 1996 we found emission-line strengths that varied by up to 20% on time scales of approximately one rotation period and one year.
8. We also found a complex H profile consisting of a variable, narrow absorption component at the H rest wavelength and a constantly blue-shifted emission component. These variations are likely to be caused by a combination of rotationally modulated chromospheric emission due to plages or possibly flares and a stellar wind of the order of 10 km s^-1. Further studies with higher time and phase resolution are needed, however, to uniquely determine their cause.

© European Southern Observatory (ESO) 1997

Online publication: July 3, 1998
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