- Published on 06 January 2016
In section 1. Letters
2MASS J18082002-5104378: The brightest (V=11.9) ultra metal-poor star
This paper presents the discovery of the brightest (V=11.9) ultra metal-poor star ([Fe/H]=-4.1dex), 2MASS J18082002−5104378. The star was selected by looking for misclassified objects, with differences between the expected spectral type based on effective temperatures and their actual spectral classification in large spectroscopic surveys. This star was followed up first with a medium-resolution spectrum from EFOSC2 at the NTT and then with a high-resolution spectrum with VLT/UVES. The abundance pattern is typical of a normal, not carbon-enhanced, ultra metal-poor star. The lack of carbon enhancement is unusual for this low [Fe/H], which makes it an important object in understanding chemical enrichment processes in the early Milky way environment. This star is also found to be part of a binary system..