Hubble Space Telescope has detected a deep space activity — 32 light years away — where an angry red dwarf star is tearing one of its own planets apart.
The star — less than 100 million years old red dwarf AU Microscopii (AU Mic) — resides 32 light-years away from Earth, outside our planetary system. It is home to the oldest planets ever detected in the universe. Our sun is 4.6-billion-year-old.
This system was identified for the first time by the US space agency Nasa’s retired Spitzer Space Telescope and the Transiting Exoplanet Survey Satellite in 2020. Using the star’s brightness, it was also detected some planets residing in the system.
Upon the first orbit, Hubble did not detect anything but at the second time a year and a half later, it was seen that the closest planet was violently being destructed by the radiation of its star evaporating the planet’s hydrogen atmosphere.
The findings are set to publish in The Astronomical Journal.
Keighley Rockcliffe, a doctoral candidate in physics and astronomy at Dartmouth College in Hanover, New Hampshire, said: “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.”
“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,'” Rockcliffe said.
Though they are cooler than the sun, red dwarfs are known to experience violent outbursts of ultraviolet and X-ray radiation in their initial days
This radiation is destroying AU Mic b — located 6 million miles from the star.
“This frankly strange observation is kind of a stress-test case for the modeling and the physics about planetary evolution,” Rockliffe said.
“This observation is so cool because we’re getting to probe this interplay between the star and the planet that is really at the most extreme.”
As the material is released from the star that forms due to the motions of the stellar atmosphere, it sends powerful bursts, hitting the planet with its radiation.
“This creates a really unconstrained and frankly, scary, stellar wind environment that’s impacting the planet’s atmosphere,” Rockcliffe said.
Astronomers are also studying and looking for habitable planets within the red dwarf system.
“We want to find out what kinds of planets can survive these environments. What will they finally look like when the star settles down? And would there be any chance of habitability eventually, or will they wind up just being scorched planets?” Rockcliffe said.
“Do they eventually lose most of their atmospheres and their surviving cores become super-Earths? We don’t really know what those final compositions look like because we don’t have anything like that in our solar system.”
After the cosmic event, astronomers are finding answers to further questions about the planet’s life and its composition, studying its evolution.
