Narrator: NASA’s TESS and Spitzer observatories have found a long-sought world orbiting the star AU Microscopii, or AU Mic for short. Located about 32 light-years away, the system will be a touchstone for understanding planetary evolution for decades to come.

AU Mic is a red dwarf star at least 150 times younger than our Sun. It’s so young that a vast disk of dust and icy grains still surrounds it.

The planet, AU Mic b, orbits very close to its star within a central zone where the disk material is cleared away.

TESS data show the newly discovered planet is about 8% larger than Neptune, with no more than about 3.4 times its mass.

TESS finds worlds like AU Mic b by catching tiny, regular dips in starlight called transits.

Spitzer, now decommissioned, confirmed the transits during its final year of operations.

The planet’s host star is very young. Flares and other phenomena also alter its brightness, which complicated the search. In order to find AU Mic b, the science team had to remove these effects from the data.

AU Mic is a nearby laboratory for studying how stars and planets form and evolve. Studying AU Mic b with future missions will also tell us more about the development and evolution of planetary atmospheres.

Until then, TESS will continue to hunt for more mysterious worlds…

…including possibly others orbiting AU Mic.