Orbital and atmospheric parameters of two wide O-type subdwarf binaries: BD-11(o)162 and Feige 80

0555511 - ASÚ 2023 RIV FR eng J - Článek v odborném periodiku
Molina, F. - Vos, J. - Németh, Péter - Østensen, R. - Vuković, M. - Tkachenko, A. - Van Winckel, H.
Orbital and atmospheric parameters of two wide O-type subdwarf binaries: BD-11(o)162 and Feige 80.
Astronomy & Astrophysics. Roč. 658, February (2022), č. článku A122. ISSN 0004-6361. E-ISSN 1432-0746
Grant CEP: GA ČR(CZ) GA18-20083S
Institucionální podpora: RVO:67985815
Klíčová slova: galactic chemical evolution * helium white-dwarfs * final mass relation
Obor OECD: Astronomy (including astrophysics,space science)
Impakt faktor: 6.5, rok: 2022
Způsob publikování: Open access s časovým embargem
https://doi.org/10.1051/0004-6361/202141220

In this study, we aim to solve orbital and atmospheric parameters of two long-period sdO binaries and, for the first time, investigate the chemical composition of their main-sequence (MS) companions. HERMES high-resolution spectra are used to obtain radial velocities and solve their orbits. The GSSP code is used to derive the atmospheric parameters and photospheric chemical abundances of the MS companions. Stellar evolution models (MIST) are fitted to the companion atmospheric parameters to derive masses. The orbital and atmospheric parameters have been fully solved. Masses of the companions and the sdOs were obtained. The photospheric chemical abundances of the MS stars for elements with available lines in the optical range have been derived. They match general trends expected from Galactic chemical evolution but show a depletion of yttrium in both systems and an enrichment of carbon in the BD-11(o)162 MS. Conclusions. In the bimodal period-eccentricity diagram, the orbital parameters indicate that Feige 80 matches the same correlation as the majority of the systems. The analysis suggests that Feige 80 has a canonical subdwarf mass and followed a standard formation channel. However, BD-11(o)162 is an exceptional system with a lower mass. It also shows a C overabundance, which could be caused by a higher progenitor mass. The Y depletion in the MS companions could indicate the existence of a circumbinary disk in these systems' pasts. Nevertheless, a chemical analysis of a larger sample is necessary to draw strong conclusions.
Trvalý link: http://hdl.handle.net/11104/0330932