Circumstellar molecular envelopes of AGB and post-AGB objects |
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| Authors: | Hans Olofsson |
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| Institution: | (1) Dipartimento di Astronomia, Università degli Studi, v. Tiepolo 11, I-34131 Trieste, Italy;(2) Institut d'Astrophysique, Centre National de La Recherche Scientifique, 98bis, Bd. Arago, F-75014 Paris, France;(3) Université de Paris Sud XI, Paris, France |
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| Abstract: | The line Li I 6708 has been sought in a sample of spectra of slow-rotating Ap stars, selected on the basis of their richness in metallic lines. The problem of the determination of the atmospheric parameters T
eff
and log g from colour indices is discussed. More than 20 per cent of the stars show an absorption line at  6708, but the presence of this feature, among Ap stars, appears to be erratic. Its identification as Li I is discussed and the parameters needed to obtain meaningful lithium abundances are examined.Based on observations collected at the European Southern Observatory (ESO), La Silla, Chile and at the Observatoire de Haute Provence (OHP), Saint Michel l'Observatoire, France. |
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