S. -B. Qian, L. -Y. Zhu, Z. -B. Dai, E. Fernández Lajús, F. -Y. Xiang, J. -J. He
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 $\dot{P}=-9.2\times{10^{-12}}$). 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 $M_3\sin{i^{\prime}}=2.3(\pm0.3)$\,$M_{Jupiter}$ when a total mass of
0.60\,$M_{\odot}$ 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 ($\sim2.5$$M_{Jupiter}$) in the
system.
View original:
http://arxiv.org/abs/1112.4269
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