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Wen-Cong Chen, On the Origin of Orbital Period Change in WY Cancri: A Genuine Angular-Momentum Loss?, Publications of the Astronomical Society of Japan, Volume 65, Issue 3, 25 June 2013, L4, https://doi.org/10.1093/pasj/65.3.L4
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Abstract
WY Cnc is a short-period (|$ P$||$ =$| 0.829 d) eclipsing RS Canum Venaticorum star, and both components are of the late-type stars. Recently, observations provided by photometric observations and light-time minima show that the orbital period of WY Cnc is experiencing a secular decrease at a rate of |$ {d}P/{d}t$||$ =$||$-$| 1.2 |$ \times$| 10|$ ^{-7}$| d yr|$ ^{-1}$| . In this letter, we consider whether the period change of WY Cnc can originate from angular-momentum loss. In calculations, we assumed that this source has a high wind loss rate of |$ \sim$| 10|$ ^{-10}$||$ M_{\odot}$| yr|$ ^{-1}$| . To account for the observation, magnetic braking demands a strong surface magnetic field of |$ \gtrsim$| 10000 G, like that of Ap/Bp stars. Furthermore, if this source is perhaps surrounded by a circumbinary disk, and 6% of the wind loss feeds the disk, the tidal torque between the disk and the binary can account for the observed angular-momentum loss rate. Such a strong magnetic field, or an extremely high wind input fraction, seems to be highly unlikely.
