We present the discovery of a hot Jupiter transiting the V = 9.23 mag main-sequence A-star KELT-17 (BD+14 1881). KELT-17b is a 1.31+0.28-0.29 MJ, 1.525+0.065-0.060 RJ hot-Jupiter in a 3.08-day period orbit misaligned at -115.°9 ± 4.°1 to the rotation axis of the star. The planet is confirmed via both the detection of the radial velocity orbit, and the Doppler tomographic detection of the shadow of the planet during two transits. The nature of the spin-orbit misaligned transit geometry allows us to place a constraint on the level of differential rotation in the host star; we find that KELT-17 is consistent with both rigid-body rotation and solar differential rotation rates (α<0.30 at 2σ significance). KELT-17 is only the fourth A-star with a confirmed transiting planet, and with a mass of 1.635+0.066-0.061 MΘ, an effective temperature of 7454 ± 49 K, and a projected rotational velocity of v sinI∗ = 44.2+1.5-1.3 kms-1 it is among the most massive, hottest, and most rapidly rotating of known planet hosts.
- Planets and satellites: individual (KELT-17b)
- stars: individual (KELT-17, BD+14 1881, TYC 807-903-1)