NGTS-8b and NGTS-9b non-inflated hot Jupiters

These orbit a V=13.68 K0V star (T_eff_=5241+/-50K) with a period of 2.49970d, and a V=12.80 F8V star (T_eff_=6330+/-130K) in 4.43527d, respectively. The transits were independently verified by follow-up photometric observations with the South African Astronomical Observatory 1.0-m and Euler telescopes, and we report on the planetary parameters using HARPS, FEROS, and CORALIE radial velocities.

NGTS-8b has a mass, 0.93^+0.04^_-0.03_M_J_ and a radius, 1.09+/-0.03R_J_ similar to Jupiter, resulting in a density of 0.89^+0.08^_-0.07_gcm^-3^. This is in contrast to NGTS-9b, which has a mass of 2.90+/-0.17M_J_ and a radius of 1.07+/-0.06R_J_, resulting in a much greater density of 2.93^+0.53^_-0.49_gcm^-3^. Statistically, the planetary parameters put both objects in the regime where they would be expected to exhibit larger than predicted radii.