# Circumbinary Planet(s?) at NY Vir

## Circumbinary Planet(s?) at NY Vir

Circumbinary Planets Orbiting the Rapidly Pulsating Subdwarf B-type binary NY Vir
http://arxiv.org/abs/1112.4269

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.

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Sirius_Alpha

Number of posts : 3388
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Registration date : 2008-04-06

## Re: Circumbinary Planet(s?) at NY Vir

Nice to see so much cataclysmic variables and dwarf novae hosting even multi-planet system.

Next I bet to be exoplanet hosts may be QS Vir, OY Car, RR Cae and UU Aqr.

Edasich
dM star

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## Re: Circumbinary Planet(s?) at NY Vir

The Pulsating sdB+M Eclipsing System NY Virginis and its Circumbinary Planets
http://arxiv.org/abs/1409.4907

We searched for circumbinary planets orbiting NY Vir in historical eclipse times including our long-term CCD data. Sixty-eight times of minimum light with accuracies better than 10 s were used for the ephemeris computations. The best fit to those timings indicated that the orbital period of NY Vir has varied due to a combination of two sinusoids with periods of P 3 =8.2 yr and P 4 =27.0 yr and semi-amplitudes of K 3 =6.9 s and K 4 =27.3 s, respectively. The periodic variations most likely arise from a pair of light-time effects due to the presence of third and fourth bodies that are gravitationally bound to the eclipsing pair. We have derived the orbital parameters and the minimum masses, M 3 sini 3 = 2.8 M Jup and M 4 sini 4 = 4.5 M Jup , of both objects. A dynamical analysis suggests that the outer companion is less likely to orbit the binary on a circular orbit. Instead we show that future timing data might push its eccentricity to moderate values for which the system exhibits long-term stability. The results demonstrate that NY Vir is probably a star-planet system, which consists of a very close binary star and two giant planets. The period ratio P 3 /P 4 suggests that a long-term gravitational interaction between them would result in capture into a nearly 3:10 mean motion resonance. When the presence of the circumbinary planets is verified and understood more comprehensively, the formation and evolution of this planetary system should be advanced greatly.

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Sirius_Alpha

Number of posts : 3388
Location : Earth
Registration date : 2008-04-06

## Re: Circumbinary Planet(s?) at NY Vir

So finally they start doing dynamical analysis in the discovery papers. Still would be nice to have some other way of checking that these variations are actually due to planets. I guess the dynamical timescales for planet-planet interactions are too long to observe for any of the proposed PCEB planetary systems.

Lazarus
dG star

Number of posts : 2752
Registration date : 2008-06-12

## Re: Circumbinary Planet(s?) at NY Vir

Everyone, try to keep back your shock and surprise.

Observing NY Vir and the quest for circumbinary planets
http://arxiv.org/abs/1608.00078

We add 9 new observations of NY Vir and identify four others from AASVO database. Our results indicate that the one and two exo-planet predictions made by earlier authors do match these new results.

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Sirius_Alpha

Number of posts : 3388
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Registration date : 2008-04-06