2014/10/22 by E. Jofré, R. Petrucci, C. Saffe +6 · 4 citations
Physics and Astronomy · #Astro and Planetary Science #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph.EP #astro-ph.SR
paper · pdf · doi:10.1051/0004-6361/201424474
published as A&A 574, A50 (2015) · 49 pages, 31 figures, Accepted for publication in A&A, abstract shortened - corrected references, typos, acknowledgements included
openalex publication_date 2014/10/22 · arxiv created 2014/11/19 · arxiv updated 2015/01/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04
We present fundamental stellar parameters and chemical abundances for a sample of 86 evolved stars with planets and for a control sample of 137 stars without planets. The analysis was based on both high S/N and resolution echelle spectra. The goals of this work are i) to investigate chemical differences between stars with and without planets; ii) to explore potential differences between the properties of the planets around giants and subgiants; and iii) to search for possible correlations between these properties and the chemical abundances of their host stars. In agreement with previous studies, we find that subgiants with planets are, on average, more metal-rich than subgiants without planets by ~ 0.16 dex. The [Fe/H] distribution of giants with planets is centered at slightly subsolar metallicities and there is no metallicity enhancement relative to the [Fe/H] distribution of giants without planets. Furthermore, contrary to recent results, we do not find any clear difference between the metallicity distributions of stars with and without planets for giants with M > 1.5 Msun. With regard to the other chemical elements, the analysis of the [X/Fe] distributions shows differences between giants with and without planets for some elements, particularly V, Co, and Ba. Analyzing the planet properties, some interesting trends might be emerging: i) multi-planet systems around evolved stars show a slight metallicity enhancement compared with single-planet systems; ii) planets with a \lesssim 0.5 AU orbit subgiants with [Fe/H] > 0 and giants hosting planets with a \lesssim 1 AU have [Fe/H] < 0; iii) higher-mass planets tend to orbit more metal-poor giants with M < 1.5 Msun, whereas planets around subgiants seem to follow the planet-mass metallicity trend observed on dwarf hosts; iv) planets orbiting giants show lower orbital eccentricities than those orbiting subgiants and dwarfs.