Fundamental parameters of two O9-type giant stars: the (former) spectral classification standard HD 93249 A and ALS 12502 A

Ansín, T.; Gamen, R.; Morrell, N. I.; Barbá, R. H.; Maíz Apellániz, J.; Arias, J. I.; Simón-Díaz, S.; Holgado, G.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society

Advertised on:
11
2023
Number of authors
8
IAC number of authors
1
Citations
2
Refereed citations
0
Description
The evolution of massive stars is not completely understood. Several phenomena affect their birth, life, and death, multiplicity being one of them. In this context, the OWN and MONOS projects are systematically observing O- and WN-type stars whose multiplicity status is unknown. Their major goal considers the necessity of determining absolute parameters of massive stars. We have collected spectra of HD 93249 A and ALS 12502 A aiming at characterizing their binary nature. For both stars, we analysed high-resolution spectra and combined them with Transiting Exoplanet Survey Satellite (TESS) observations to be compared with binary models constructed by means of the PHOEBE code. We discovered that the radial velocity of HD 93249 A varies with a period of 2.97968 ± 0.00001 d and that the system presents ellipsoidal light variations. We disentangled the composite spectra and classified its components as O9 III and B1.5 III, respectively. Confirmed as a spectroscopic binary, HD 93249 A can no longer be used as spectral classification standard. ALS 12502 A turned out to be a detached eclipsing binary in the TESS and Gaia data. These results enable us to determine absolute parameters for each component in the system.
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Physical properties and evolution of Massive Stars
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Sergio
Simón Díaz