The very massive x-ray bright binary system wack 2134 (= wr 21a)
| Autor: | Pablo Reig, G. R. Solivella, Rodolfo H. Barbá, Virpi S. Niemela, M. J. Coe, Roberto Claudio Gamen, Paula Benaglia, E. Fernández Lajús |
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| Jazyk: | angličtina |
| Rok vydání: | 2008 |
| Předmět: |
individual: Wack 2134 [Stars]
Ciencias Astronómicas Absorption spectroscopy Ciencias Físicas FOS: Physical sciences Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Binaries: spectroscopic Spectral line purl.org/becyt/ford/1 [https] spectroscopic [Binaries] Stars: Wolf-Rayet Emission spectrum Binary system Astrophysics::Galaxy Astrophysics Physics Stars: individual: WR 21a individual: WR 21a [Stars] Stars: individual: Wack 2134 Astrophysics (astro-ph) Astronomy and Astrophysics purl.org/becyt/ford/1.3 [https] Orbital period Wolf-Rayet [Stars] Radial velocity Astronomía Stars Amplitude Space and Planetary Science Astrophysics::Earth and Planetary Astrophysics CIENCIAS NATURALES Y EXACTAS |
| Zdroj: | MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY Artículos CONICYT CONICYT Chile instacron:CONICYT CONICET Digital (CONICET) Consejo Nacional de Investigaciones Científicas y Técnicas instacron:CONICET SEDICI (UNLP) Universidad Nacional de La Plata instacron:UNLP |
| Popis: | From the radial velocities of the N IV λ4058 and He II λ4686 emission lines, and the N v λ4604-20 absorption lines, determined in digital spectra, we report the discovery that the X-ray bright emission line star Wack 2134 (= WR 21a) is a spectroscopic binary system with an orbital period of 31.673 ± 0.002 d. With this period, the N IV and He II emission and N v absorption lines, which originate in the atmosphere of the primary component, define a rather eccentric binary orbit (e = 0.64 ± 0.03). The radial velocity variations of the N v absorptions have a lower amplitude than those of the He II emission. Such a behaviour of the emission line radial velocities could be due to distortions produced by a superimposed absorption component from the companion. High-resolution echelle spectra observed during the quadrature phases of the binary show H and He II absorptions of both components with a radial velocity difference of about 541 km s-1. From this difference, we infer quite high values of the minimum masses, of about 87 and 53 M⊙ for the primary and secondary components, respectively, if the radial velocity variations of the He II emission represent the true orbit of the primary. No He i absorption lines are observed in our spectra. Thus, the secondary component in the Wack 2134 binary system appears to be an early O-type star. From the presence of H, He II and N v absorptions, and N IV and C IV emissions, in the spectrum of the primary component, it most clearly resembles those of Of/WNLha-type stars. Facultad de Ciencias Astronómicas y Geofísicas Instituto Argentino de Radioastronomía |
| Databáze: | OpenAIRE |
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