From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Sep 14 2005 - 15:47:55 UTC
astro-ph/0509326 [abs, ps, pdf, other] :
Title: Oxygen abundances in planet-harbouring stars. Comparison of different
abundance indicators
Authors: A. Ecuvillon (1), G. Israelian (1), N. C. Santos (2,3), N. G.
Shchukina (4), M. Mayor (3), R. Rebolo (1,5) ((1)IAC, Spain, (2)Observatorio
Astronomico de Lisboa, Portugal, (3) Observatoire de Geneve, Switzerland,
(4)Main Astronomical Observatory, Ukraine, (5)CSIC, Spain)
Comments: 19 pages, 11 figures (low resolution), accepted for publication in
A&A
We present a detailed and uniform study of oxygen abundances in 155 solar
type stars, 96 of which are planet hosts and 59 of which form part of a
volume-limited comparison sample with no known planets. EW measurements were
carried out for the [O I] 6300 \AA line and the O I triplet, and spectral
synthesis was performed for several OH lines. NLTE corrections were
calculated and applied to the LTE abundance results derived from the O I
7771-5 \AA\ triplet. Abundances from [O I], the O I triplet and near-UV OH
were obtained in 103, 87 and 77 dwarfs, respectively. We present the first
detailed and uniform comparison of these three oxygen indicators in a large
sample of solar-type stars. There is good agreement between the [O/H] ratios
from forbidden and OH lines, while the NLTE triplet shows a systematically
lower abundance. We found that discrepancies between OH, [O I] and the O I
triplet do not exceed 0.2 dex in most cases. We have studied abundance
trends in planet host and comparison sample stars, and no obvious anomalies
related to the presence of planets have been detected. All three indicators
show that, on average, [O/Fe] decreases with [Fe/H] in the metallicity range
-0.8<[Fe/H]<0.5. The planet host stars present an average oxygen
overabundance of 0.1-0.2dex with respect to the comparison sample.
http://arxiv.org/abs/astro-ph/0509326
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