Volume 397, Number 3, January III 2003
|Page(s)||987 - 995|
|Section||Stellar structure and evolution|
|Published online||21 January 2003|
Fast-rotating nearby solar-type stars *,**
II. Li abundances, v sin i and X-ray luminosities relationships
INAF – Catania Astrophysical Observatory, v. S. Sofia 78, 95125 Catania, Italy e-mail: firstname.lastname@example.org
2 INAF – Brera Astronomical Observatory, via Bianchi 46, 22055 Merate (LC), Italy e-mail: email@example.com; firstname.lastname@example.org
3 University Federal of Rio Grande do Norte, Department of Physics, 59072-970 Natal, R.N., Brazil e-mail: email@example.com
4 European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei München, Germany e-mail: firstname.lastname@example.org
5 Astronomical Observatory, NBIfAFG, Juliane Maries Vej 30, 2100 Copenhagen, Denmark e-mail: email@example.com
Corresponding author: G. Cutispoto, firstname.lastname@example.org
Accepted: 28 October 2002
We present an analysis of our high-resolution spectroscopic and high-precision photometric observations of a sample of 110 nearby late-F and G-type stars selected for their large rotational velocity. The relationships between Li abundance, X–ray luminosity, and are investigated. We find that, as expected, the stars in our sample show statistically higher Li abundance and activity level than field star samples with similar characteristics, but slower rotation. Surprisingly, however, we also find four rapidly-rotating single main-sequence stars with very low Li abundance. For both single and binary stars we find a large spread of Li abundance for stars with rotation lower than about 18 . The well-established correlation between X–ray luminosity and rotation rate is clearly observed. All single unevolved solar type stars with larger than 18 are strong X–ray emitters and have high Li abundance. Finally, we find also five evolved stars with very low Li abundance that are still rather fast rotators. The results from our sample confirm the presence of young very active stars close to the Sun, in agreement with recent findings from EUV and X–ray surveys, although our sample does not show such extreme characteristics as those selected from EUV and X–ray surveys at the current flux limits.
Key words: stars: abundances / stars: activity / stars: fundamental parameters / stars: variables: general / X-rays: stars
© ESO, 2003
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