Oxygen Abundances: New Results from [O I] Lines

Oxygen abundances in metal - poor subgiants as determined from [ O i ] , O i and OH lines ⋆

Oxygen in Galactic Disk Stars : non - LTE abundances from the 777 nm O I triplet

Oxygen abundances for a large sample of dwarf and giant stars kinematically selected to be part of the Galactic thin and thick disks have been determined from a non-LTE analysis of the O I triplet lines at 777 nm. The abundance analysis was performed using the infrared flux method temperature scale, trigonometric surface gravities, and accurate atomic data. Within this framework, the ionization...

OXYGEN LINE FORMATION IN LATE-F THROUGH EARLY-K DISK/HALO STARS: INFRARED O i TRIPLET AND [O i] LINES

In order to investigate the formation of O i 7771–5 and [O i] 6300/6363 lines, extensive non-LTE calculations for neutral atomic oxygen were carried out for wide ranges of model atmosphere parameters, which are applicable to early-K through late-F halo/disk stars of various evolutionary stages. A useful formula with tabulated numerical coefficients is presented, applicable to evaluating NLTE co...

Oxygen abundances in unevolved metal-poor stars from near-UV OH lines

We have performed a detailed oxygen abundance analysis of 23 metal-poor (−3.0<[Fe/H]< −0.3) unevolved halo stars and one giant through the OH bands in the near UV, using high-resolution echelle spectra. Oxygen is found to be overabundant with respect to iron in these stars, with the [O/Fe] ratio increasing from 0.6 to 1 between [Fe/H]=−1.5 and −3.0. The behavior of the oxygen overabundance with...

OXYGEN ABUNDANCES IN METAL-POOR STARS (−2.2 < [Fe/H] < −1.2) FROM INFRARED OH LINES

Infrared OH lines at 1.55 1.56 μm in the H-band were obtained with the Phoenix high-resolution spectrograph at the 2.1m telescope of the Kitt Peak National Observatory for a sample of 14 metal-poor stars. Detailed analyses of the sample stars have been carried out, deriving stellar parameters based on two methods: (a) spectroscopic parameters; (b) IRFM effective temperatures, trigonometric grav...