A Differential Study of the Oxygen Abundances in the Galactic Thin and Thick Disks

Summary, in English

First results from a study into the abundance trends of oxygen in the Galactic thin and thick disks are presented. Oxygen abundances for 63nearby F and G dwarf stars, based on very high resolution spectra (R∼215 000) and high signal-to-noise (S/N>400) of the faint forbidden oxygen line at 6300Å, have been determined. Our findings can be summarized as follows: 1) at [Fe/H]<0 the oxygen trends in thethin and thick disk are smooth and distinct, indicating their different origins, 2) [O/Fe] for the thick disk stars show a turn-over at[Fe/H]∼-0.35, indicating the peak of the enrichment from SNe type Ia to the interstellar medium, 3) the thin disk stars show a shallow decrease going from [Fe/H] ∼-0.7 to the highest metallicities with no apparent turn-over present indicating a more quiet star formation history, and 4) [O/Fe] continues to decrease at [Fe/H] > 0 without showing the leveling out that previously has been seen.

• Author: Thomas Bensby; Sofia Feltzing; Ingemar Lundström
• Department/s: Lund Observatory - Has been reorganised
• Publishing year: 2004
• Language: English
• Publication/Series: Carnegie Observatories Astrophysics Series, Origin and Evolution of the Elements
• Volume: 4
• Document type: Conference paper
• Publisher: Carnegie Observatories
• Topic: Astronomy, Astrophysics and Cosmology
• Status: Published