Indication of a massive circumbinary planet orbiting the low-mass X-ray binary MXB 1658-298

作者：Jain Chetana^*; Paul Biswajit^*; Sharma Rahul; Jaleel Abdul; Dutta Anjan

来源：Monthly Notices of the Royal Astronomical Society, 2017, 468(1): L118-L122.

DOI：10.1093/mnrasl/slx039

• planet-star interactions
• binaries: eclipsing
• stars: neutron
• X-rays: binaries

We present an X-ray timing analysis of the transient X-ray binary MXB 1658-298, using data obtained from the RXTE and XMM-Newton observatories. We have made 27 new mid-eclipse time measurements from observations made during the two outbursts of the source. These new measurements have been combined with the previously known values to study long-term changes in orbital period of the binary system. We have found that the mid-eclipse timing record of MXB 1658-298 is quite unusual. The long-term evolution of mid-eclipse times indicates an overall orbital period decay with a time-scale of -6.5(7) x 10(7) yr. Over and above this orbital period decay, the O-C residual curve also shows a periodic residual on shorter time-scales. This sinusoidal variation has an amplitude of similar to 9 lt-s and a period of similar to 760 d. This is indicative of the presence of a third body around the compact X-ray binary. The mass and orbital radius of the third body are estimated to lie in the ranges 20.5-26.9 Jupiter mass and 750-860 lt-s, respectively. If true, then it will be the most massive circumbinary planet and also the smallest period binary known to host a planet.

• 出版日期2017-6