Pelisoli, I., Marsh, T.R., Dhillon, V.S. et al. (9 more authors) (Submitted: 2021) Found : a rapidly spinning white dwarf in LAMOST J024048.51+195226.9. arXiv. (Submitted)
Abstract
We present optical photometry of the cataclysmic variable LAMOST J024048.51+195226.9 taken with the high-speed, five-band CCD camera HiPERCAM on the 10.4 m Gran Telescopio Canarias (GTC). We detect pulsations originating from the spin of its white dwarf, finding a spin period of 24.9328(38)s. The pulse amplitude is of the order of 0.2% in the g-band, below the detection limits of previous searches. This detection establishes LAMOST J024048.51+195226.9 as only the second white dwarf magnetic propeller system, a twin of its long-known predecessor, AE Aquarii. At 24.93s, the white dwarf in LAMOST J024048.51+195226.9 has the shortest known spin period of any cataclysmic variable star. The white dwarf must have a mass of at least 0.7MSun to sustain so short a period. The observed faintest u-band magnitude sets an upper limit on the white dwarf's temperature of ~25000K. The pulsation amplitudes measured in the five HiPERCAM filters are consistent with an accretion spot of ~30000K covering ~2% of the white dwarf's visible area, although much hotter and smaller spots cannot be ruled out.
Metadata
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Copyright, Publisher and Additional Information: | © 2021 The Authors. | ||||||
Keywords: | binaries: general; stars: cataclysmic variables; binaries: close | ||||||
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Institution: | The University of Sheffield | ||||||
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > Department of Physics and Astronomy (Sheffield) | ||||||
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Depositing User: | Symplectic Sheffield | ||||||
Date Deposited: | 10 Sep 2021 07:19 | ||||||
Last Modified: | 23 Jan 2023 17:13 | ||||||
Status: | Submitted | ||||||
Identification Number: | https://doi.org/10.48550/arXiv.2108.11396 | ||||||
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