Wednesday, July 20, 2016

Hot Planet Orbiting a Rapidly-Rotating A-Type Star

Zhou et al. (2016) present the discovery of a hot-Jupiter transiting a massive, rapidly-rotating A-type star. The planet is identified as KELT-17b. Transit and radial velocity observations indicate that KELT-17b has ~1.31 times the mass and ~1.525 times the radius of Jupiter. The planet's orbital period is 3.08 days. The host star of KELT-17b has ~1.635 times the mass, ~1.645 times the radius and ~7.51 times the luminosity of the Sun. It is a rapidly-rotating star with a rotation speed of at least 44.2 km/s. Also, its effective temperature is 7454 K. The host star of KELT-17b is one of the most massive, hottest, and most rapidly-rotating star with a known planet. Furthermore, the orbit of KELT-17b is severely misaligned. KELT-17b is only the fourth hot-Jupiter found transiting an A-type star, after WASP-33b, KOI-13b, and HAT-P-57b. All four hot-Jupiters orbiting A-type stars are in severely misaligned orbits.

Zhou et al. (2016), "KELT-17b: A hot-Jupiter transiting an A-star in a misaligned orbit detected with Doppler tomography", arXiv:1607.03512 [astro-ph.EP]