Letter to the Editor
A Spectroscopic study of the non-thermal radio emitter Cyg OB2 #8A: Discovery of a new binary system*
Institut d'Astrophysique et de Géophysique, Université de Liège, 17, Allée du 6 Août, B5c, 4000 Sart Tilman, Belgium e-mail: firstname.lastname@example.org
Accepted: 2 August 2004
We present the results of a spectroscopic campaign revealing that the non-thermal radio emitter Cyg OB2 #8A is an O6 + O5.5 binary system. We propose the very first orbital solution indicating a period of about 21.9 days. The system appears to be eccentric (0.24 ± 0.04) and is likely seen under a rather low inclination angle. The mass ratio of the components is close to unity. The impact of the binarity of this star in the framework of our understanding of non-thermal radio emission from early-type stars is briefly discussed.
Key words: binaries: spectroscopic / stars: early-type / stars: fundamental parameters / stars: individual: Cyg OB2 #8A
© ESO, 2004