Reference : Observational signatures of past mass-exchange episodes in massive binaries: the case...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/211075
Observational signatures of past mass-exchange episodes in massive binaries: the case of LSS 3074
English
Raucq, Françoise mailto [Université de Liège > > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Gosset, Eric mailto [Université de Liège > > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Rauw, Grégor mailto [Université de Liège > > Groupe d'astrophysique des hautes énergies (GAPHE) >]
Manfroid, Jean mailto [Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Département d'astrophys., géophysique et océanographie (AGO) >]
Mahy, Laurent mailto [Université de Liège > Département d'astrophys., géophysique et océanographie (AGO) > Astroph. extragalactique et observations spatiales (AEOS) >]
Mennekens, Nicki [Vrije Universiteit Brussel - VUB > > Astronomy and Astrophysics Research Group > >]
Vanbeveren, Danny [Vrije Universiteit Brussel - VUB > > Astronomy and Astrophysics Research Group > >]
2017
Astronomy and Astrophysics
EDP Sciences
601
A133
Yes (verified by ORBi)
International
0004-6361
1432-0746
Les Ulis
France
[en] stars: early-type ; binaries: spectroscopic ; stars: fundamental parameters ; stars: massive ; stars: individual: LSS 3074
[en] Context. The role of mass and momentum exchanges in close massive binaries is very important in the subsequent evolution of the components. Such exchanges produce several observational signatures such as asynchronous rotation and altered chemical compositions,
that remain after the stars detach again.
Aims. We investigated these effects for the close O-star binary LSS 3074 (O4 f + O6-7:(f):), which is a good candidate for a past Roche lobe overflow (RLOF) episode because of its very short orbital period, P = 2.185 days, and the luminosity classes of both components.
Methods.We determined a new orbital solution for the system. We studied the photometric light curves to determine the inclination of the orbit and Roche lobe filling factors of both stars. Using phase-resolved spectroscopy, we performed the disentangling of the optical spectra of the two stars.We then analysed the reconstructed primary and secondary spectra with the CMFGEN model atmosphere code to determine stellar parameters, such as the effective temperatures and surface gravities, and to constrain the chemical composition of the components.
Results. We confirm the apparent low stellar masses and radii reported in previous studies. We also find a strong overabundance in nitrogen and a strong carbon and oxygen depletion in both primary and secondary atmospheres, together with a strong enrichment in helium of the primary star.
Conclusions. We propose several possible evolutionary pathways through a RLOF process to explain the current parameters of the system. We confirm that the system is apparently in overcontact configuration and has lost a significant portion of its mass to its surroundings. We suggest that some of the discrepancies between the spectroscopic and photometric properties of LSS 3074 could stem from the impact of a strong radiation pressure of the primary.
Fonds de la Recherche Scientifique (Communauté française de Belgique) - F.R.S.-FNRS
Researchers ; Students
http://hdl.handle.net/2268/211075
10.1051/0004-6361/201630330
http://adsabs.harvard.edu/abs/2017arXiv170303247R

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