Kavli Affiliate: Saul A. Rappaport
| First 5 Authors: Colin Littlefield, D. W. Hoard, Peter Garnavich, Paula Szkody, Paul A. Mason
| Summary:
There have been relatively few published long-duration, uninterrupted light
curves of magnetic cataclysmic variable stars in which the accreting white
dwarf’s rotational frequency is slightly desynchronized from the binary orbital
frequency (asynchronous polars). We report Kepler K2 and TESS observations of
two such systems. The first, SDSS J084617.11+245344.1, was observed by the
Kepler spacecraft for 80 days during Campaign 16 of the K2 mission, and we
identify it as a new asynchronous polar with a likely 4.64 h orbital period.
This is significantly longer than any other asynchronous polar, as well as all
but several synchronous polars. Its spin and orbital periods beat against each
other to produce a conspicuous 6.77 d beat period, across which the system’s
accretion geometry gradually changes. The second system in this study, Paloma,
was observed by TESS for one sector and was already known to be asynchronous.
Until now, there had been an ambiguity in its spin period, but the TESS power
spectrum pinpoints a spin period of 2.27 h. During the resulting 0.7 d
spin-orbit beat period, the light curve phased on the spin modulation
alternates between being single- and double-humped. We explore two possible
explanations for this behavior: the accretion flow being diverted from one of
the poles for part of the beat cycle, or an eclipse of the emitting region
responsible for the second hump.
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