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 |$1.330^{+0.024}_{-0.028}$|MJ and |$1.271^{+0.197}_{-0.188}$|RJ, respectively, returning a planetary bulk density of |$0.711^{+0.214}_{-0.136}$| 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.

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