Bibcode
Delgado Mena, E.; Adibekyan, V. Zh.; Figueira, P.; González Hernández, J. I.; Santos, N. C.; Tsantaki, M.; Sousa, S. G.; Faria, J. P.; Suárez-Andrés, L.; Israelian, G.
Bibliographical reference
Publications of the Astronomical Society of the Pacific, Volume 130, Issue 991, pp. 094202 (2018).
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9
2018
Citations
11
Refereed citations
11
Description
To understand the formation and composition of planetary systems it is
important to study their host stars composition since both are formed in
the same stellar nebula. In this work, we analyze the behaviour of
chemical abundances of Cu, Zn, Sr, Y, Zr, Ba, Ce, Nd, and Eu in the
large and homogeneous HARPS-GTO planet search sample (R ˜ 115000).
This sample is composed of 120 stars hosting high-mass planets, 29 stars
hosting exclusively Neptunians and Super-Earths and 910 stars without
detected giant planets. We compare the [X/Fe] ratios of such elements in
different metallicity bins and we find that planet hosts present higher
abundances of Zn for [Fe/H] < -0.1 dex. On the other hand, Ba,
Sr, Ce, and Zr abundances are underabundant in stars with planets, with
a bigger difference for stars only hosting low-mass planets. However,
most of the offsets found can be explained by differences in stellar
parameters and by the fact that planet hosts at low metallicity mostly
belong to the Galactic thick disk. Only in the case of Ba we find a
statistically significant (3σ) underabundance of 0.03 dex for
low-mass planet hosts. The origin of these elements is quite complex due
to their evolution during the history of the Galaxy. Therefore, it is
necessary to understand and characterize the stellar populations to
which planet hosts belong in order to do a fair comparison with stars
without detected planets. This work demonstrates that the effects of
Galactic chemical evolution and not the presence of planets mostly
account for the differences we find.
Based on observations collected at the La Silla Observatory, ESO
(Chile), with the HARPS spectrograph at the 3.6 m ESO telescope (ESO
runs ID 72.C—0488, 082.C—0212, and 085.C—0063).
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
Garik
Israelian