A detailed study of lithium in 107 CHEPS dwarf stars
Author
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Pavlenko, Ya. V.
Author
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Jenkins, James Stewart
Author
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Ivanyuk, O. M.
Author
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Jones, H. R. A.
Author
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Kaminsky, B. M.
Author
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Lyubchik, Yu. P.
Author
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Yakovina, L. A.
Admission date
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2018-07-17T15:55:59Z
Available date
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2018-07-17T15:55:59Z
Publication date
dc.date.issued
2018
Cita de ítem
dc.identifier.citation
Astronomy & Astrophysics, 611, A27 (2018)
es_ES
Identifier
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10.1051/0004-6361/201731547
Identifier
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https://repositorio.uchile.cl/handle/2250/149901
Abstract
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Context. We report results from lithium abundance determinations using high resolution spectral analysis of the 107 metal-rich stars from the Calan-Hertfordshire Extrasolar Planet Search programme.
Aims. We aim to set out to understand the lithium distribution of the population of stars taken from this survey.
Methods. The lithium abundance taking account of non-local thermodynamical equilibrium effects was determined from the fits to the Li I 6708 angstrom resonance doublet profiles in the observed spectra.
Results. We find that a) fast rotators tend to have higher lithium abundances; b) log N(Li) is higher in more massive and hot stars; c) log N(Li) is higher in stars of lower log g; d) stars with the metallicities >0.25 dex do not show the lithium lines in their spectra; e) most of our planet hosts rotate slower; and f) a lower limit of lithium isotopic ratio is Li-7/Li-6 > 10 in the atmospheres of two stars with planets (SWP) and two non-SWP stars.
Conclusions. Measurable lithium abundances were found in the atmospheres of 45 stars located at distances of 20 170 pc from the Sun, for the other 62 stars the upper limits of log N(Li) were computed. We found well defined dependences of lithium abundances on T-eff, V sin i, and less pronounced for the log g. In case of V sin i we see two sequences of stars: with measurable lithium and with the upper limit of log N(Li). About 10% of our targets are known to host planets. Only two SWP have notable lithium abundances, so we found a lower proportion of stars with detectable Li among known planet hosts than among stars without planets. However, given the small sample size of our planet-host sample, our analysis does not show any statistically significant differences in the lithium abundance between SWP and stars without known planets.
es_ES
Patrocinador
dc.description.sponsorship
EU PF7 Marie Curie Initial Training Networks (ITN) RoPACS project
213646
Fondecyt grant
1161218
CATA-Basal (CONICYT)
PB06
UK STFC
ST/M001008/1
Leverhulme Trust
RPG-2014-281
NAS Ukraine under the Main Astronomical Observatory GRAPE/GPU/GRID computing cluster project