English

Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir

Solar and Stellar Astrophysics 2015-06-03 v1

Abstract

We report here the tentative discovery of a Jovian planet in orbit around the rapidly pulsating subdwarf B-type (sdB-type) eclipsing binary NY Vir. By using new determined eclipse times together with those collected from the literature, we detect that the observed-calculated (O-C) curve of NY Vir shows a small-amplitude cyclic variation with a period of 7.9\,years and a semiamplitude of 6.1\,s, while it undergoes a downward parabolic change (revealing a period decrease at a rate of P˙=9.2×1012\dot{P}=-9.2\times{10^{-12}}). The periodic variation was analyzed for the light-travel time effect via the presence of a third body. The mass of the tertiary companion was determined to be M3sini=2.3(±0.3)M_3\sin{i^{\prime}}=2.3(\pm0.3)\,MJupiterM_{Jupiter} when a total mass of 0.60\,MM_{\odot} for NY Vir is adopted. This suggests that it is most probably a giant circumbinary planet orbiting NY Vir at a distance of about 3.3 astronomical units (AU). Since the rate of period decrease can not be explained by true angular momentum loss caused by gravitational radiation or/and magnetic braking, the observed downward parabolic change in the O-C diagram may be only a part of a long-period (longer than 15 years) cyclic variation, which may reveal the presence of another Jovian planet (2.5\sim2.5MJupiterM_{Jupiter}) in the system.

Keywords

Cite

@article{arxiv.1112.4269,
  title  = {Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir},
  author = {S. -B. Qian and L. -Y. Zhu and Z. -B. Dai and E. Fernández Lajús and F. -Y. Xiang and J. -J. He},
  journal= {arXiv preprint arXiv:1112.4269},
  year   = {2015}
}

Comments

12 pages, 3 figures, accepted by ApJ Letters

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