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Astron. Astrophys. 321, L17-L20 (1997)


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Letter to the Editor

A stellar endgame - the born-again Sakurai's object

M. Asplund 1, B. Gustafsson 1, D.L. Lambert 2 and N. Kameswara Rao 3

1 Astronomiska observatoriet, Box 515, S-751 20  Uppsala, Sweden
2 Department of Astronomy, University of Texas, Austin, TX 78712, USA
3 Indian Institute of Astrophysics, Bangalore 560 034, India

Received 7 February 1997 / Accepted 13 March 1997

Abstract

The surface chemical composition of this remarkable star shows that it is hydrogen-deficient, carbon-rich and enriched in the light s -process elements. Spectra taken in May and October 1996 indicate a decrease in the surface hydrogen abundance by 0.7 dex in five months along with an increase in the abundances of Li, Sr, Y and Zr. The abundance changes are in agreement with the hypothesis of the star being a rapidly evolving "born-again" AGB star experiencing a final He-shell flash, similar to FG Sge. The 12 C/13 C ratio in October is very low, also suggesting hydrogen ingestion. By chemical composition, Sakurai's object resembles the R Coronae Borealis (R CrB) stars.

Key words: Stars: individual: Sakurai's object – Stars: evolution – Stars: AGB and post-AGB – Stars: abundances – Stars: variables: other – Stars: individual: FG Sge

Send offprint requests to: M. Asplund (martin@astro.uu.se)

© European Southern Observatory (ESO) 1997

Online publication: June 30, 1998

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