Located less than 32 light-years from Earth, AU Microscopii is among the youngest planetary systems ever observed by astronomers, and its star throws vicious temper tantrums! You’ve heard of the “terrible twos”? Well, AU Mic is in the midst of its terrible 22 … millions!

This devilish young system holds planet AU Mic b captive inside a looming disk of ghostly dust and ceaselessly torments it with deadly blasts of X-rays and other radiation, thwarting any chance of life… as we know it! Beware! There is no escaping the stellar fury of this system. The monstrous flares of AU Mic will have you begging for eternal darkness.

The planet, AU Microscopii b, is a gas giant exoplanet that orbits the young M-type star. Its mass is 0.18 Jupiters, it takes 8.5 days to complete one orbit of its star, and is 0.066 AU from its star. Its discovery was announced in 2020.

In July 2023, researchers using NASA's Hubble Space Telescope saw the planet being blasted by its star and puffing off the hydrogen in its atmosphere. More observations revealed that the planet seemed to be ''hiccuping.'' On one orbit, the planet was seen puffing up, during another, no such atmospheric loss was noted.

"We've never seen atmospheric escape go from completely not detectable to very detectable over such a short period when a planet passes in front of its star," said Keighley Rockcliffe of Dartmouth College in Hanover, New Hampshire. "We were really expecting something very predictable, repeatable. But it turned out to be weird. When I first saw this, I thought 'That can't be right.'"

PLANET TYPE
Neptune-like
DISCOVERY DATE
2020
MASS
20.12 Earths
PLANET RADIUS
0.353 x Jupiter
ORBITAL RADIUS
0.0645 AU
ORBITAL PERIOD
8.5 days
ECCENTRICITY
0.19
DETECTION METHOD