Chemical abundances of planet-host stars

Abstract

Abstract. In this paper, we present a study of the abundances of Si, Ca, Sc, Ti, V, Cr, Mn, Co, and Ni in a large set of stars known to harbor giant planets, as well as in a comparison sample of stars not known to have any planetary-mass companions. We have checked for possible chemical differences between planet hosts and field stars without known planets. Our results show that overall, and for a given value of [Fe/H], the abundance trends for the planet hosts are nearly indistinguishable from those of the field stars. In general, the trends show no discontinuities, and the abundance distributions of stars with giant planets are high [Fe/H] extensions to the curves traced by the field dwarfs without planets. The only elements that might present slight differences between the two groups of stars are V, Mn, and to a lesser extent Ti and Co. We also use the available data to describe galactic chemical evolution trends for the elements studied. When comparing the results with former studies, a few differences emerge for the high [Fe/H] tail of the distribution, a region that is sampled with unprecedented detail in our analysis.

Chemical abundances of 451 stars from the HARPS GTO planet search program

“…This difference is also above the results of Bond et al (2006) for all elements. Our results are, on average, similar to those of Bodaghee et al (2003) and Gilli et al (2006). The dispersion in this differences for all elements is the smallest of all authors, which probably attests to the quality of our results.…”

“…Gradually, similar abundance studies were made for elements other than iron (e.g. Gonzalez et al 2001;Sadakane et al 2002;Israelian et al 2003;Bodaghee et al 2003;Beirão et al 2005;Fischer & Valenti 2005;Gilli et al 2006;Ecuvillon et al 2006;Takeda 2007). The same abundance difference was observed in these elements, suggesting that the probability of finding a giant planet is strongly related to the abundance content of its host star.…”

“…In this section, we analyse them only to determine whether there are any differences in the abundances of stars with and without planets, for the same value of [Fe/H]. The reported cases of potential trends described by other authors such as, for instance, Sadakane et al (2002) for vanadium and cobalt, Bodaghee et al (2003) for Ti, Mn, V, and Co, and Gilli et al (2006) for V, Co, Mg, and Al, were not found. Robinson et al (2006) claimed to have found clear and significant overabundances of [Si/Fe] and [Ni/Fe].…”

“…These potential differences were detected for some elements (e.g. Si, Ti, Mn, V, Co, Ni, Na, and Mg - Bodaghee et al 2003;Gilli et al 2006;Robinson et al 2006) and are difficult to explain with galactic chemicalevolution models. Despite that, the results obtained are still contradictory and no definitive conclusion has yet been reached.…”

Binarity, activity and metallicity among late-type stars

“…Additional error sources are due to NLTE effects, which are known to affect a few elements, like Fe (discussed in Sect. 4.1), V, Mn and to a lesser extent Ti (Bodaghee et al 2003). For the remaining elements the effects are unknown or uncertain.…”