High speed stars - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Astronomy and Astrophysics - A&A Année : 2024

High speed stars

E. Caffau
  • Fonction : Auteur correspondant
P. Bonifacio
  • Fonction : Auteur
L. Monaco
  • Fonction : Auteur
L. Sbordone
  • Fonction : Auteur
M. Spite
  • Fonction : Auteur
P. François
P. Panuzzo
  • Fonction : Auteur
P. Sartoretti
  • Fonction : Auteur
L. Chemin
  • Fonction : Auteur
F. Thévenin
  • Fonction : Auteur
A. Mucciarelli
  • Fonction : Auteur

Résumé

Context. The Gaia satellite has provided the community with three releases containing astrometrical and photometric data as well as by products, such as stellar parameters and variability indicators.Aims. By selecting in the Gaia database, one can select stars with the requested characteristics, such as high speed. At present any selection is based on available Gaia releases including a subset of the observations. This, for some stars, can show some limitations, for example there is still not a sufficient number of observations to detect binarity.Methods. We investigated a star selected in Gaia EDR3 for its high speed that appears unbound to the Galaxy. We requested high-quality spectra to derive more information on the star.Results. From the spectroscopic investigation we confirm the low metallicity content of the star, and we derive a detailed chemical composition. The star is poor in carbon and very rich in oxygen: [(C+N+O)/Fe] = +0.65. From the two spectra observed we conclude that the star is in a binary system and from the investigation of the ionisation balance we derive that the star is closer than implied by the Gaia DR3 parallax, and thus has a a lower intrinsic luminosity.Conclusions. The star is probably still unbound, but there is the possibility that it is bound to the Galaxy. Its low carbon abundance suggests that the star was formed in a dwarf galaxy.
Fichier principal
Vignette du fichier
aa49485-24.pdf (374.31 Ko) Télécharger le fichier
Origine : Publication financée par une institution

Dates et versions

hal-04538010 , version 1 (08-04-2024)

Identifiants

Citer

E. Caffau, P. Bonifacio, L. Monaco, L. Sbordone, M. Spite, et al.. High speed stars: III. Detailed abundances and binary nature of the extreme speed star GHS143. Astronomy and Astrophysics - A&A, 2024, 684, pp.L4. ⟨10.1051/0004-6361/202449485⟩. ⟨hal-04538010⟩
0 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More