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The Temperature Scale of Metal-Poor Dwarfs: Lithium and Oxygen Abundances

Jorge Melendez·Nataliya G. Shchukina·Ivan Ramirez·Irina Vasiljeva
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Abstract

We employ a new Infrared Flux Method (IRFM) temperature scale (Ramirez & Melendez 2005, ApJ 626, 446; ApJ 626, 465) in order to determine Li, O, and Fe NLTE abundances in a sample of relatively unevolved (dwarfs, turn-off, subgiants) metal-poor stars. We show that the analysis of the permitted OI triplet and FeII lines leads to a plateau in [OI/FeII] over the broad metallicity range -3.2 < [Fe/H] < -0.7, independent of temperature and metallicity, and with a star-to-star scatter of only 0.1 dex. The Li abundance in halo stars is also found to be independent of temperature and metallicity (Spite plateau), with a star-to-star scatter of just 0.06 dex over the metallicity range -3.4 < [Fe/H] < -1. Our Li abundance (Melendez & Ramirez 2004, ApJ 615, L33) is higher than previously reported values, but still lower than the primordial abundance suggested by WMAP data and BBN.

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Jorge Melendez, Nataliya G. Shchukina, Ivan Ramirez, Irina Vasiljeva. 2005-07-06. The Temperature Scale of Metal-Poor Dwarfs: Lithium and Oxygen Abundances. https://doi.org/10.1017/s1743921305005752

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