The CEMP star SDSSJ0222-0313: the first evidence of proton ingestion in very low-metallicity AGB stars? - Observatoire de Paris Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2019

The CEMP star SDSSJ0222-0313: the first evidence of proton ingestion in very low-metallicity AGB stars?

Résumé

Context. Carbon-enhanced metal-poor (CEMP) stars are common objects in the metal-poor regime. The lower the metallicity we look at, the larger the fraction of CEMP stars with respect to metal-poor stars with no enhancement in carbon. The chemical pattern of CEMP stars is diversified, strongly suggesting a different origin of the C enhancement in the different types of CEMP stars. Aims. We selected a CEMP star, SDSS J0222-0313, with a known high carbon abundance and, from a low-resolution analysis, a strong enhancement in neutron-capture elements of the first peak (Sr and Y) and of the second peak (Ba). The peculiarity of this object is a greater overabundance (with respect to iron) of the first s-process peak than the second s-process peak. Methods. We analysed a high-resolution spectrum obtained with the Mike spectrograph at the Clay Magellan 6.5 m telescope in order to derive the detailed chemical composition of this star. Results. We confirmed the chemical pattern we expected; we derived abundances for a total of 18 elements and significant upper limits. Conclusions. We conclude that this star is a carbon-enhanced metal-poor star enriched in elements produced by s-process (CEMP-s), whose enhancement in heavy elements is due to mass transfer from the more evolved companion in its asymptotic giant branch (AGB) phase. The abundances imply that the evolved companion had a low main sequence mass and it suggests that it experienced a proton ingestion episode at the beginning of its AGB phase.
Fichier principal
Vignette du fichier
j0222m0313_final.pdf (314.19 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

obspm-02202783 , version 1 (31-07-2019)

Identifiants

Citer

E. Caffau, L. Monaco, P. Bonifacio, S. Korotin, S. Andrievsky, et al.. The CEMP star SDSSJ0222-0313: the first evidence of proton ingestion in very low-metallicity AGB stars?. Astronomy and Astrophysics - A&A, In press, 628, ⟨10.1051/0004-6361/201935680⟩. ⟨obspm-02202783⟩
112 Consultations
78 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More