Lithium in the binary halo star HD 89499

Abstract

view Abstract Citations (12) References (50) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Lithium in the Binary Halo Star HD 89499 Balachandran, Suchitra ; Carney, Bruce W. ; Fry, Anne M. ; Fullton, Laura K. ; Peterson, Ruth C. Abstract We report the finding of an unusually large Li abundance in the tidally locked binary halo star HD 89499. The effective temperature of this star has been determined to be 4900 +/- 150 K from photometric and spectroscopic analyses. Its metallicity has been determined to be Fe/H = -2.08 +/- 0.07 from 26 Fe I lines, and its rotational velocity is estimated to be 22 +/- 4 km/s. If the star is a dwarf, its Li abundance is 1.35 which is a factor of 10-30 above that for other halo dwarfs of the same temperature. In this case, the Li depletion may have been arrested when the rotational period of the star tidally synchronized with the binary orbital period. The rotational velocity is not consistent with a tidally locked dwarf in an ancient 6 day binary system; either the orbital period is incorrect or the star is evolved. We discuss the difficulties in assigning HD 89499 such an evolved status, but note it is marginally possible, in which case its Li abundance is still a factor of 3 higher than comparable temperature halo subgiants. Publication: The Astrophysical Journal Pub Date: August 1993 DOI: 10.1086/173005 Bibcode: 1993ApJ...413..368B Keywords: Binary Stars; Metallicity; Stellar Composition; Stellar Evolution; Halos; Lithium; Stellar Models; Astrophysics; STARS: BINARIES: CLOSE; STARS: ABUNDANCES; STARS: EVOLUTION; STARS: INDIVIDUAL HENRY DRAPER NUMBER: HD 89499 full text sources ADS | data products SIMBAD (5)