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arXiv · 1702.06311

Rapid orbital decay in detached binaries: evidence for circumbinary disks

Wen-Cong Chen·Philipp Podsiadlowski
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Abstract

Some short-period, detached binary systems have recently been reported to experience very rapid orbital decay, much faster than is expected from the angular-momentum loss caused by gravitational radiation alone. As these systems contain fully convective stars, magnetic braking is not believed to be operative, making the large orbital-period derivative puzzling. Here we explore whether a resonant interaction between the binary and a surrounding circumbinary (CB) disk could account for the observed orbital decay. Our calculations indicate that the observed orbital-period derivatives in seven detached binaries can be produced by the resonant interaction between the binary and a CB disk if the latter has a mass in the range of $10^{-4}-10^{-2}~ M_{\odot}$, which is of the same order as the inferred disk mass ($\sim2.4\times 10^{-4}~ M_{\odot}$) in the post-common-envelope binary NN Ser.

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Wen-Cong Chen, Philipp Podsiadlowski. 2017-02-21. Rapid orbital decay in detached binaries: evidence for circumbinary disks. https://doi.org/10.3847/2041-8213%2Faa624a

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