Bibcode
Adibekyan, V. Zh.; Sousa, S. G.; Santos, N. C.; Delgado Mena, E.; González-Hernández, J. I.; Israelian, G.; Mayor, M.; Khachatryan, G.
Bibliographical reference
Astronomy and Astrophysics, Volume 545, id.A32
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9
2012
Journal
Citations
494
Refereed citations
436
Description
Context. We performed a uniform and detailed abundance analysis of 12
refractory elements (Na, Mg, Al, Si, Ca, Ti, Cr, Ni, Co, Sc, Mn, and V)
for a sample of 1111 FGK dwarf stars from the HARPS GTO planet search
program. Of these stars, 109 are known to harbor giant planetary
companions and 26 stars are exclusively hosting Neptunians and
super-Earths. Aims: The two main goals of this paper are to
investigate whether there are any differences between the elemental
abundance trends for stars of different stellar populations and to
characterize the planet host and non-host samples in terms of their
[X/H]. The extensive study of this sample, focused on the abundance
differences between stars with and without planets will be presented in
a parallel paper. Methods: The equivalent widths of spectral
lines were automatically measured from HARPS spectra with the ARES code.
The abundances of the chemical elements were determined using an LTE
abundance analysis relative to the Sun, with the 2010 revised version of
the spectral synthesis code MOOG and a grid of Kurucz ATLAS9
atmospheres. To separate the Galactic stellar populations we applied
both a purely kinematical approach and a chemical method.
Results: We found that the chemically separated (based on the Mg, Si,
and Ti abundances) thin- and thick disks are also chemically disjunct
for Al, Sc, Co, and Ca. Some bifurcation might also exist for Na, V, Ni,
and Mn, but there is no clear boundary of their [X/Fe] ratios. We
confirm that an overabundance in giant-planet host stars is clear for
all studied elements.We also confirm that stars hosting only
Neptunian-like planets may be easier to detect around stars with similar
metallicities than around non-planet hosts, although for some elements
(particulary α-elements) the lower limit of [X/H] is very abrupt.
Based on observations collected at the La Silla Paranal Observatory, ESO
(Chile) with the HARPS spectrograph at the 3.6-m telescope (ESO runs ID
72.C-0488, 082.C-0212, and 085.C-0063).Full Tables 4, 5, and the table
with EWs of the lines are only available at the CDS via anonymous ftp to
cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/545/A32Figure
A.1 is available in electronic form at http://www.aanda.org
Related projects
Observational Tests of the Processes of Nucleosynthesis in the Universe
Several spectroscopic analyses of stars with planets have recently been carried out. One of the most remarkable results is that planet-harbouring stars are on average more metal-rich than solar-type disc stars. Two main explanations have been suggested to link this metallicity excess with the presence of planets. The first of these, the “self
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Israelian