Kelt-21b: A hot Jupiter transiting the rapidly-rotating metal-poor late-A primary of a likely hierarchical triple system

Detection of the line profile perturbations confirmed that the planet candidate Kelt-21b does indeed transit its rapidly rotating host star. Furthermore, the motion of the line profile perturbation across the line profile during the transit diagnosted the spin-orbit misalignment, which is the angle between the stellar spin and planetary orbital angular momentum vectors projected onto the plane of the sky.

The Doppler tomographic PEPSI data for KELT-21. Time is from bottom up. Vertical lines mark the center of the line profile at v=0 and the edges at v = v sin i, a horizontal line shows the time of mid-transit, and the four small crosses depict the times of first through fourth contacts.


Read more: Johnson et al. 2018, AJ, 2018, 155, 100