AO Vel: un notable sistema cuádruple con una primario BpSi y dos componentes de Hg-Mn

GONZÁLEZ, J. F.; NESVACIL, N.; HUBRIG, S.; WOLFF, B.

Capilla del Monte, Córdoba, Argentina

Congreso; 49 Reunión Anual de la Asociación Argentina de Astronomía; 2006

Asociación Argentina de Astronomía

We present a study of chemical abundances of all four stellar components of AOVel, a multiple system recently reported as a spectroscopic quadruple system with components very close to the ZAMS (González et al. 2006). The temperature obtained for components A, B, C, and D are 13 700, 12 200, 12 000, and 11 500 K, respectively. Star A exhibits an overabundance of Si by 1.0 dex and an underabundance of He by -0.5 dex. Star B is a normal late B-type star with abundances close to solar. Stars C and D present spectral lines typical for HgMn stars, although very few MnII lines have been identi_ed. Star C shows a strong overabundance of Hg by 6.7 dex, while other metals (Fe, Ti, Mg and Si) show solar abundances. Star D exhibits, besides Hg, overabundance of  YII (3.1 dex), Pt I (5 dex), and Sr II (2.2 dex). The measured wavelength of Hg II 3984 indicates that the heavy Hg isotopes 202 and 204 are predominant in components C and D. A more detailed study, including spectral synthesis is planned to provide limits on the Mn abundance.