Chemical Abundances in Metal-Rich Bulge-like Stars

Abstract

Abstract. We have derived chemical abundances for Ca, Ti, Si, Mg, O, Na, Al, Ni, Co and Cr for a sample of stars with peculiar kinematics and probable origin near the bulge. Our sample stars are in the metallicity range = −0.8 [Fe/H] +0.6 dex, and have small pericentric distances, Rp 3.5 kpc, small scale height, with Zmax < 0.16 kpc, and old ages, 9 to 11 Gyr. We have found that the abundance distributions of O, Mg and Al lie between bulge and both thin and thick disks distributions, i. e., with an enhanced pattern relative to thin and thick disk stars, and an underabundant behavior compared to bulge stars. [Na/Fe] ratios ovelarp the bulge distribution in the metal-poor tail, and show similar values compared to thin and thick disk stars for the super-solar metallicity range. Ca, Ti and Si values are similar to those of the thick disk stars in the metal-poor range, while an underabundant behavior is seen relative to thin disk stars for metallicities [Fe/H] > +0.3 dex. Compared to bulge stars, such elements are deficient in our sample stas. For the iron-peak elements Cr and Ni we have found a slightly overabundant behavior relative to both thin and thick disks distributions in the metal-poor range, and a smooth decreasing trend for [Cr/Fe] for stars in the supersolar regime. [Co/Fe] ratios track the solar value in the metal-poor range, and show an underabundant behavior relative do thin disk stars for metallicities [Fe/H] > 0.0 dex.

Analysis of old very metal rich stars in the solar neighbourhood

“…5.3. Ti, Si, and Ni spectral lines were selected A42, page 13 of 26 from Bensby et al (2004), Cohen et al (2009), andPompéia et al (2007). Through a similar procedure used in the iron abundance determination, the log g f values were fitted to the solar equivalent widths, adopting (Ti/H) = 5.02, (Si/H) = 7.55 and (Ni/H) = 6.25 (Grevesse & Sauval 1998).…”

Formação e evolução de galáxias: populações estelares na Via Láctea, galáxias elípticas e propriedades de galáxias em grupos

“…2.5.3. Ti, Si, and Ni spectral lines were selected from Bensby et al (2004), Cohen et al (2009), andPompéia et al (2007). Through a similar procedure used in the iron abundance determination, the log g f values were fitted to the solar equivalent widths, adopting (Ti/H) ⊙ = 5.02, (Si/H) ⊙ = 7.55 and (Ni/H) ⊙ = 6.25 (Grevesse & Sauval, 1998).…”