Spectroscopic searches for evolutionary orbital period changes in WR+OB binaries: the case of V444 Cygстатья
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Дата последнего поиска статьи во внешних источниках: 15 февраля 2024 г.
Аннотация:We present the results of new photometric and spectroscopic observations of the WN5+O6 binary V444 Cyg and a detailed analysis of extant spectroscopy and photometry. Using elements of the spectroscopic orbit and assuming e ≈ 0, i ≈ 78° we determined the masses and orbit sizes of the components of V444 Cyg as M_O6 ≈ 26.4 Msun, M_WN5 ≈ 10.7 Msun, a_O6 ≈ 10.6 Rsun, a_WN5 ≈ 26.1 Rsun. Based on new and archival light curves and using the Hertzsprung method, we improved the photometric estimate of the secular increase rate of the orbital period in V444 Cyg, obtaining Ṗ_ph=0.119±0.003 s yr^-1. From a comparison of the new and archival radial velocity curves of V444 Cyg, we independently derived the secular orbital period change rate as Ṗ_sp=0.147±0.032 s yr^-1, in agreement with the photometric Ṗ_ph . The obtained secular increase rate of the binary orbital period Ṗ and the mean radii of the components enabled us to estimate the stellar wind mass-loss rate from the WR star as Ṁ_WN5=−(6.0±0.4)×10^−6 Msun yr^−1.