Martins, F;
Foschino, S;
Bouret, J-C;
Barba, R;
Howarth, I;
(2016)
Surface abundances of OC supergiants.
Astronomy & Astrophysics
, 588
, Article A64. 10.1051/0004-6361/201628288.
Preview |
Text
Howarth_stv2568.pdf - Published Version Download (1MB) | Preview |
Abstract
Some O and B stars show unusually strong or weak lines of carbon and/or nitrogen. These objects are classified as OBN or OBC stars. It has recently been shown that nitrogen enrichment and carbon depletion are the most likely explanations for the existence of the ON class. We investigate OC stars (all being supergiants) to check that surface abundances are responsible for the observed anomalous line strengths. We perform a spectroscopic analysis of three OC supergiants using atmosphere models. A fourth star was previously studied by us. Our sample thus comprises all OC stars known to date in the Galaxy. We determine the stellar parameters and He, C, N, and O surface abundances. We show that all stars have effective temperatures and surface gravities fully consistent with morphologically normal O supergiants. However, OC stars show little, if any, nitrogen enrichment and carbon surface abundances consistent with the initial composition. OC supergiants are thus barely chemically evolved, unlike morphologically normal O supergiants.
Type: | Article |
---|---|
Title: | Surface abundances of OC supergiants |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1051/0004-6361/201628288 |
Publisher version: | http://dx.doi.org/10.1051/0004-6361/201628288 |
Language: | English |
Keywords: | Science & Technology, Physical Sciences, Astronomy & Astrophysics, stars: massive, stars: abundances, stars: fundamental parameters, stars: early-type, Galactic O, Spectroscopic Survey, Massive Stars, Rotational Velocities, Binary Frequency, Magnetic-field, Zeta Orionis, Obc Stars, Cno Stars, Nitrogen |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
URI: | https://discovery.ucl.ac.uk/id/eprint/1479624 |
Archive Staff Only
View Item |