UBV photometry, UV spectroscopy and radio observations of the peculiar binary V Sagittae |
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| Authors: | J J Lockley Janet H Wood S P S Eyres T Naylor Sergei Shugarov |
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| Institution: | Department of Physics and Astronomy, University of Southampton, Highfield, Southampton SO17 1BJ; Physics Department, Keele University, Keele ST5 5BG; Sternberg Astronomical Institute, 13 University Avenue, 119899, Moscow, Russia |
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| Abstract: | We have performed high-speed UBV photometric observations on the peculiar binary V Sagittae. Using three new eclipse timings we update the orbital ephemeris and convert it to a dynamical time-scale (TDB). We also searched for quasi-periodic oscillations but did not detect them. Using the Wilson–Devinney algorithm we have modelled the light curve to find the stellar parameters of V Sge. We find that the system is a detached binary but that the primary star is very close to filling its Roche lobe, while the secondary star fills 90 per cent of its Roche lobe volume. We find temperatures of the primary and the secondary star to be T 1=41 000 K and T 2=22 000 K. We find i =72° and masses of 0.8 M⊙ and 3.3 M⊙ for the primary and secondary stars respectively. De-archived Hubble Space Telescope ( HST ) spectroscopy of V Sge shows evidence of mass loss via a wind or winds. In addition we report radio observations of V Sge during an optical high state at 2 cm, 3.6 cm and 6 cm wavelengths. The 3.6 cm emission is increased by a factor of more than six compared with an earlier detection in a previous optical high state. |
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| Keywords: | binaries: eclipsing stars: individual: V Sge stars: mass-loss stars: variables: other radio continuum: stars ultraviolet: stars |
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