TOPoS: III. An ultra iron-poor multiple CEMP system ?
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Archivos
Fecha
2016-11
Profesor/a Guía
Facultad/escuela
Idioma
en
Título de la revista
ISSN de la revista
Título del volumen
Editor
EDP Sciences
Nombre de Curso
Licencia CC
Atribution 4.0 International (CC BY 4.0)
Licencia CC
https://creativecommons.org/licenses/by/4.0/deed.es
Resumen
Aims. One of the primary objectives of the TOPoS survey is to search for the most metal-poor stars. Our search has led to the discovery
of one of the most iron-poor objects known, SDSS J092912.32+023817.0. This object is a multiple system, in which two components
are clearly detected in the spectrum.
Methods. We have analysed 16 high-resolution spectra obtained using the UVES spectrograph at the ESO 8.2 m VLT telescope to
measure radial velocities and determine the chemical composition of the system.
Results. Cross correlation of the spectra with a synthetic template yields a double-peaked cross-correlation function (CCF) for eight
spectra, and in one case there is evidence for the presence of a third peak. Chemical analysis of the spectrum obtained by averaging
all the spectra for which the CCF showed a single peak found that the iron abundance is [Fe/H] = −4.97. The system is also
carbon enhanced with [C/Fe] = +3.91 (A(C) = 7.44). From the permitted oxygen triplet we determined an upper limit for oxygen
of [O/Fe] < +3.52 such that C/O > 1.3. We are also able to provide more stringent upper limits on the Sr and Ba abundances
([Sr/Fe] < +0.70, and [Ba/Fe] < +1.46, respectively).
Notas
Indexación: Scopus.
Palabras clave
Stars: Population II, Stars: Abundances, Binaries: Spectroscopic, Galaxy: Abundances, Galaxy: Halo
Citación
Astronomy and Astrophysics. Volume 595. 1 November 2016. Article number L6
DOI
10.1051/0004-6361/201629776