Abstract

We report the discovery of a new ultrashort period hot Jupiter from the Next Generation Transit Survey. NGTS-6b orbits its star with a period of 21.17 h, and has a mass and radius of 1.330(-0.028)(+0.024)M(J) and 1.271(-0.188)(+0.197)R(J), respectively, returning a planetary bulk density of 0.711(-0.136)(+0.214) g cm(-3). Conforming to the currently known small population of ultrashort period hot Jupiters, the planet appears to orbit a metal-rich star ([Fe/H]=+0.11 +/- 0.09 dex). Photoevaporation models suggest the planet should have lost 5 per cent of its gaseous atmosphere over the course of the 9.6 Gyr of evolution of the system. NGTS-6b adds to the small, but growing list of ultrashort period gas giant planets, and will help us to understand the dominant formation and evolutionary mechanisms that govern this population.