The massive double-lined O-type binary HD 165052 |
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| Authors: | J I Arias † N I Morrell ‡ R H Barbá G L Bosch § M Grosso ¶ M Corcoran |
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| Institution: | Facultad de Ciencias Astronómicas y Geofísicas, Universidad Nacional de La Plata, Paseo del Bosque S/N, B1900FWA La Plata, Argentina,; Complejo Astronómico El Leoncito, Av. España 1512 sur, 5400 San Juan, Argentina,; Universities Space Research Association, 7501 Forbes Blvd, Ste 206, Seabrook, MD 20706, USA and; Laboratory for High Energy Astrophysics, Goddard Space Flight Center, Greenbelt MD 20771, USA |
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| Abstract: | We present a new optical spectroscopic study of the O-type binary HD 165052 based on high- and intermediate-resolution CCD observations. We re-investigated the spectral classification of the binary components, obtaining spectral types of O6.5 V and O7.5 V for the primary and secondary, respectively, finding that both stars display weak C iii λ 5696 emission in their spectra. We also determined a radial-velocity orbit for HD 165052 with a period of 2.95510±0.00001 d , and semi-amplitudes of 94.8 and 104.7±0.5 km s-1 , resulting in a mass ratio Q =0.9 . From a comparison with previous radial-velocity determinations, we found evidence of apsidal motion in the system. Several signatures of wind–wind collision, such as phase-locked variability of the X-ray flux and the Struve–Sahade effect, are also considered. It was also found that the reddening in the region should be normal, in contrast with previous determinations. |
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| Keywords: | binaries: general stars: early-type stars: individual: HD 165052 X-rays: stars |
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