Close binary systems in the regions of OB-associations. II. AT Vulpeculae in Vul OBl and EV Vulpeculae in Vul OB4
| 1Zakirov, MM, 2Eshankulova, MU 1Uzbekistan National University, 100174, Vuzgorodok, Tashkent, Uzbekistan 2Astronomical Institute, Academy of Sciences of Uzbekistan, ul. Astronomicheskaya 33, 100052, Tashkent, Uzbekistan |
| Kinemat. fiz. nebesnyh tel (Online) 2004, 20(6):525-539 |
| Language: Russian |
Abstract: The first UBVR photoelectric observations of the eclipsing variable stars AT Vul and EV Vul were carried out at the Maidanak Observatory (Uzbekistan) in 1990—2001. We improved the ephemerides of the binaries: Min I = HJD 2429906.9276(24) + 3.9803541E + (5.75 ± 0.53)⋅10-9E2 for AT Vul and Min I = HJD2442731.1301(42) + 2.8220971E + 0.029(9)sin(0.490 + 0.0407E) for EV Vul. The orbital period for the third body in EV Vul is 436 ± 1d. All light curves of two binaries were solved by Lavrov's direct method and the orbit photometric elements for the systems were derived. The orbit of AT Vul has a small eccentricity (0.02). The expected absolute basic parameters for the components of AT Vul were estimated: Mh = 16.0M☉, Mc = 8.1M☉, Rh = 5.1R☉, Rc = 10.0R☉, Mh,bol = -5.9m, Mc,bol = -5.0m. We failed to find the absolute physical data for EV Vul. It is possible that one or both components of EV Vul have thick dust discs. The star AT Vul belongs to the OB-association Vul OB1 and the star EV Vul is a member of Vul OB4. |
| Keywords: close binary system, OB-association |
