The pulsating sdB+M eclipsing system NY Virginis and its circumbinary planets

We searched for circumbinary planets orbiting NY Vir in historical eclipse times including our long-term CCD data. 68 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...

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Veröffentlicht in:Monthly notices of the Royal Astronomical Society 2014-12, Vol.445 (3), p.2331-2339
Hauptverfasser: Lee, Jae Woo, Hinse, Tobias Cornelius, Youn, Jae-Hyuck, Han, Wonyong
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Sprache:eng
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Zusammenfassung:We searched for circumbinary planets orbiting NY Vir in historical eclipse times including our long-term CCD data. 68 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 3sin i 3 = 2.8 M Jup and M 4sin i 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.
ISSN:0035-8711
1365-2966
DOI:10.1093/mnras/stu1937