Circumbinary Planet(s?) at NY Vir

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

Quote :

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.

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.

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

Quote :

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.

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.

Everyone, try to keep back your shock and surprise.

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

Quote :

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.

Circumbinary Planets Orbiting the sdB Binary NY Virginis: An Updated Two Planet Solution
https://arxiv.org/abs/1812.01726

Quote :

We report 18 new primary minima timing observations of the short-period eclipsing binary system NY Virginis. We combined these minima with previously published primary minima to update circumbinary exoplanet models in this system based on O-C timing variations. We performed a non-linear least-squares minimization search using a quadratic ephemeris and either one or two exoplanets. The only model with an acceptable fit includes a period derivative (P˙=−2.09×10−12) and two planets in eccentric orbits with minimum masses 2.9 and 4.9 Jovian masses. However, a number of model parameters are highly degenerate, so additional observations are required to determine planetary parameters with high statistical confidence.

In a totally unprecedented development, it turns out the two-planet fit isn't stable.

Orbital Stability of Proposed NY Virginis Exoplanets
https://arxiv.org/abs/2210.00214

Quote :

As the number of these confounding systems increases, it is becoming clear that interpreting ETV variations in sdB binaries as resulting solely from gravitational perturbations from orbiting substellar objects is untenable, and that the observed ETV signatures must be at least in part a result of other physical mechanisms.

Sounds pretty reasonable to me.