The stars of the low part of the main sequence

T. V. Mishenina (1) , S. I. Belik (1) , I.A. Usenko (1) , O. Bienaymé (2) , C. Soubiran (2, 3, 4, 5) , V. V. Kovtyukh (6) , S. A. Korotin (6)

1 Odessa Astronomical Observatory
2 OAS - Observatoire astronomique de Strasbourg
3 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
4 OASU - Observatoire aquitain des sciences de l'univers
5 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
6 Astronomical observatory of Odessa National University [Odessa]

Li, and volatile (O, Na, Al, Zn) and refractory ( Si, Ti, V, Cr, Co and Ni) element abundances in 133 stars belonging to the low part of MS have been determined. Among them about 30 stars are the variable stars of BY Dra type, for which the determination of the chemical composition was made for the first time. The effective temperatures Teff were estimated by the line depth ratio method. The surface gravities log g were determined by two methods (ionization balance of iron and using parallaxes). The abundances of lithium and oxygen were determined by the calculation of synthetic spectrum. The comparison of volatile and refractory element abundances in variable stars and other stars was made. We have found that the behaviour of the abundances of the majority of elements in MS stars and spotted stars does not differ. The Li is detected in 65 % BY Dra stars and in 26 % of MS stars. The Li abundance in variable stars is higher than in MS dwarfs.

Mots clés: Stars: fundamental parameters; stars: abundances; stars: main -sequence; stars: BY Dra type.; stars: BY Dra type

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]

T. V. Mishenina, S. I. Belik, I.A. Usenko, O. Bienaymé, C. Soubiran, et al.. The stars of the low part of the main sequence. 2007. ⟨hal-00260809⟩