The very massive X-ray bright binary system Wack 2134 (= WR 21a)★
Corresponding Author
V. S. Niemela
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
R. C. Gamen
Complejo Astronómico El Leoncito, Avda. España 1412 Sur, San Juan, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
R. H. Barbá
Complejo Astronómico El Leoncito, Avda. España 1412 Sur, San Juan, Argentina
Departamento de Física, Universidad de La Serena, Benavente 980, La Serena, Chile
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
E. Fernández Lajús
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
P. Benaglia
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
Instituto Argentino de Radioastronomía, C.C.5, 1894 Villa Elisa, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
G. R. Solivella
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorP. Reig
IESL, Foundation for Research and Technology, 711 10 Heraklion, Crete, Greece
University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
Search for more papers by this authorM. J. Coe
School of Physics and Astronomy, Southampton University, Southampton SO17 1BJ
Search for more papers by this authorCorresponding Author
V. S. Niemela
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
R. C. Gamen
Complejo Astronómico El Leoncito, Avda. España 1412 Sur, San Juan, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
R. H. Barbá
Complejo Astronómico El Leoncito, Avda. España 1412 Sur, San Juan, Argentina
Departamento de Física, Universidad de La Serena, Benavente 980, La Serena, Chile
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
E. Fernández Lajús
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
P. Benaglia
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
Instituto Argentino de Radioastronomía, C.C.5, 1894 Villa Elisa, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorCorresponding Author
G. R. Solivella
Facultad de Cs. Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900 La Plata, Argentina
In memoriam (1936–2006).
E-mail: [email protected]
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile, and CASLEO, Argentina.
Member of Carrera del Investigador CONICET, Argentina. Visiting Astronomer, Las Campanas Observatory and Cerro Tololo Inter-American Observatory, Chile.
Postdoctoral Fellow CONICET, Argentina.
Member of Carrera del Investigador CONICET, Argentina.
Visiting Astronomer, CASLEO, Argentina.
Search for more papers by this authorP. Reig
IESL, Foundation for Research and Technology, 711 10 Heraklion, Crete, Greece
University of Crete, Physics Department, PO Box 2208, 710 03 Heraklion, Crete, Greece
Search for more papers by this authorM. J. Coe
School of Physics and Astronomy, Southampton University, Southampton SO17 1BJ
Search for more papers by this authorBased partially on data collected at SAAO, CASLEO, LCO, CTIO and La Silla (under programme ID 68.D-0073) Observatories.
ABSTRACT
From the radial velocities of the N ivλ4058 and He iiλ4686 emission lines, and the N vλ4604-20 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.
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