Chemical analysis of CH stars - III. Atmospheric parameters and elemental abundances

Purandardas, M.; Goswami, A.; Goswami, P. P.; Shejeelammal, J.; Masseron, T.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society, Volume 486, Issue 3, p.3266-3289

Fecha de publicación:
7
2019
Número de autores
5
Número de autores del IAC
1
Número de citas
21
Número de citas referidas
19
Descripción
Elemental abundances of CH stars can provide observational constraints for theoretical studies on the nucleosynthesis and evolution of low- and intermediate-mass stars. However, available abundance data in literature are quite scanty. In our pursuit to generate a homogeneous data base of elemental abundances of CH stars we have performed a detailed chemical abundance study for a sample of 12 potential CH star candidates based on high-resolution spectroscopy. We present first time abundance analysis for the objects HE0308-1612, CD-281082, HD30443, and HD87853. For the other objects, although limited information is available, detailed chemical composition studies are missing. Our analysis shows CD-281082 to be a very metal-poor object with [Fe/H] = -2.45 and enriched in carbon with [C/Fe] = 2.19. With a ratio of [Ba/Eu] ˜ 0.02 the star satisfies the classification criteria of a CEMP-r/s star. The objects CD-382151 with [Fe/H] = -2.03 and HD30443 with [Fe/H] ˜ -1.68 are found to show the characteristic properties of CH stars. HE0308-1612 and HD87853 are found to be moderately metal poor with [Fe/H] ˜ -0.73; while HE0308-1612 is moderately enhanced with carbon ([C/Fe] ˜ 0.78) and shows the spectral properties of CH stars, the abundance of carbon could not be estimated for HD87853. Among the two moderately metal-poor objects, HD87080 ([Fe/H] = -0.48) shows near solar carbon abundance, and HD176021 ([Fe/H] = -0.63) is mildly enhanced in carbon with [C/Fe] = 0.52. HD176021 along with HD202020 a known binary, exhibit the characteristic properties of CH stars as far as the heavy element abundances are concerned. Five objects in our sample show spectral properties that are normally seen in barium stars.
Proyectos relacionados
Project Image
Nucleosíntesis y procesos moleculares en los últimos estados de la evolución estelar

Las estrellas de masa baja e intermedia (M < 8 masas solares, Ms) representan la mayoría de estrellas en el Cosmos y terminan sus vidas en la Rama Asintótica de las Gigantes (AGB) - justo antes de formar Nebulosas Planetarias (NPs) - cuando experimentan procesos nucleosintéticos y moleculares complejos. Las estrellas AGB son importantes

Domingo Aníbal
García Hernández
spectrum of mercury lamp
Abundancias Químicas en Estrellas

La espectroscopía de estrellas nos permite determinar las propiedades y composiciones químicas de las mismas. A partir de esta información para estrellas de diferente edad en la Vía Láctea es posible reconstruir la evolución química de la Galaxia, así como el origen de los elementos más pesados que el boro, forjados principalmente en los interiores

Carlos
Allende Prieto