期刊
ASTROPHYSICAL JOURNAL
卷 709, 期 1, 页码 447-457出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/709/1/447
关键词
Galaxy: bulge; Galaxy: evolution; gravitational lensing: micro; stars: abundances
资金
- NSF [AST 0757888]
- Polish MNiSW [N20303032/4275]
- STFC [ST/H001913/1] Funding Source: UKRI
- Science and Technology Facilities Council [ST/H001913/1, ST/H00243X/1] Funding Source: researchfish
- Direct For Mathematical & Physical Scien
- Division Of Astronomical Sciences [0757888] Funding Source: National Science Foundation
We present a high-resolution spectrum of a microlensedGdwarf in the Galactic bulge with spectroscopic temperature T-eff = 5600 +/- 180 K. This I similar to 21 mag star was magnified by a factor ranging from 1160 to 1300 at the time of observation. Its high metallicity ([Fe/H] = 0.33 +/- 0.15 dex) places this star at the upper end of the bulge giant metallicity distribution. Using a Kolmogorov-Smirnov test, we find a 1.6% probability that the published microlensed bulge dwarfs share an underlying distribution with bulge giants, properly accounting for a radial bulge metallicity gradient. We obtain abundance measurements for 15 elements and perform a rigorous error analysis that includes covariances between parameters. This star, like bulge giants with the same metallicity, shows no alpha enhancement. It confirms the chemical abundance trends observed in previously analyzed bulge dwarfs. At supersolar metallicities, we observe a discrepancy between bulge giant and bulge dwarf Na abundances.
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