Wednesday, January 11, 2012

1201.2013 (T. Bensby et al.)

Signatures of an intermediate-age metal-rich bulge population    [PDF]

T. Bensby, S. Feltzing, A. Gould, J. A. Johnson, M. Asplund, D. Adén, J. Meléndez, J. G. Cohen, I. Thompson, S. Lucatello, A. Gal-Yam
We have determined detailed elemental abundances and stellar ages for a sample of now 38 microlensed dwarf and subgiant stars in the Galactic bulge. Stars with sub-solar metallicities are all old and have enhanced alpha-element abundances -- very similar to what is seen for local thick disk stars. The metal-rich stars on the other hand show a wide variety of stellar ages, ranging from 3-4 Gyr to 12 Gyr, and an average around 7-8 Gyr. The existence of young and metal-rich stars are in conflict with recent photometric studies of the bulge which claim that the bulge only contains old stars.
View original: http://arxiv.org/abs/1201.2013

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