Chemical abundances and kinematics of 257 G-, K-type field giants: setting a base for further analysis of giant-planet properties orbiting evolved stars

Adibekyan, V. Zh; Benamati, L; Santos, N. C; Alves, S; Lovis, C; Udry, S; Israelian, G; Sousa, S. G; Tsantaki, M; Mortier, A; Sozzetti, A; Medeiros, José Renan de

Chemical abundances and kinematics of 257 G-, K-type field giants: setting a base for further analysis of giant-planet properties orbiting evolved stars

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dc.contributor.author	Adibekyan, V. Zh
dc.contributor.author	Benamati, L
dc.contributor.author	Santos, N. C
dc.contributor.author	Alves, S
dc.contributor.author	Lovis, C
dc.contributor.author	Udry, S
dc.contributor.author	Israelian, G
dc.contributor.author	Sousa, S. G
dc.contributor.author	Tsantaki, M
dc.contributor.author	Mortier, A
dc.contributor.author	Sozzetti, A
dc.contributor.author	Medeiros, José Renan de
dc.date.accessioned	2020-05-31T20:26:56Z
dc.date.available	2020-05-31T20:26:56Z
dc.date.issued	2015
dc.description.resumo	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 257 G- and K-type evolved stars from the CORALIE planet search programme. To date, only one of these stars is known to harbour a planetary companion. We aimed to characterize this large sample of evolved stars in terms of chemical abundances and kinematics, thus setting a solid base for further analysis of planetary properties around giant stars. This sample, being homogeneously analysed, can be used as a comparison sample for other planet-related studies, as well as for different type of studies related to stellar and Galaxy astrophysics. The abundances of the chemical elements were determined using an local thermodynamic equilibrium (LTE) abundance analysis relative to the Sun, with the spectral synthesis code MOOG and a grid of Kurucz ATLAS9 atmospheres. To separate the Galactic stellar populations, both a purely kinematical approach and a chemical method were applied. We confirm the overabundance of Na in giant stars compared to the field FGK dwarfs. This enhancement might have a stellar evolutionary character, but departures from LTE may also produce a similar enhancement. Our chemical separation of stellar populations also suggests a ‘gap’ in metallicity between the thick-disc and high-α metal-rich stars, as previously observed in dwarfs sample from HARPS. The present sample, as most of the giant star samples, also suffers from the B − V colour cut-off, which excludes low-log g stars with high metallicities, and high-log g star with low [Fe/H]. For future studies of planet occurrence dependence on stellar metallicity around these evolved stars, we suggest to use a subsample of stars in a ‘cut-rectangle’ in the log g–[Fe/H] diagram to overcome the aforementioned issue	pt_BR
dc.identifier.citation	ADIBEKYAN, V. Z. ; BENAMATI, L. ; SANTOS, N. C. ; Alves, S. ; LOVIS, C. ; UDRY, S. ; ISRAELIAN, G. ; SOUSA, S. G. ; TSANTAKI, M. ; MORTIER, A. ; SOZZETTI, A. ; MEDEIROS, J. R de. . Chemical abundances and kinematics of 257 G-, K-type field giants. Setting a base for further analysis of giant-planet properties orbiting evolved stars. Monthly Notices of the Royal Astronomical Society, v. 450, p. 1900-1915, 2015. Disponível em: https://academic.oup.com/mnras/article/450/2/1900/983680. Acesso em: 26 Maio 2020. https://doi.org/10.1093/mnras/stv716 .	pt_BR
dc.identifier.doi	https://doi.org/10.1093/mnras/stv716
dc.identifier.uri	https://repositorio.ufrn.br/jspui/handle/123456789/29104
dc.language	en	pt_BR
dc.publisher	Oxford University Press	pt_BR
dc.subject	methods observational – techniques	pt_BR
dc.subject	Spectroscopic – stars	pt_BR
dc.subject	Abundances – planetary system	pt_BR
dc.title	Chemical abundances and kinematics of 257 G-, K-type field giants: setting a base for further analysis of giant-planet properties orbiting evolved stars	pt_BR
dc.type	article	pt_BR