NASA | GSFC | STScI | HubbleSite | 2018 Oct 18
The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by affecting their atmospheres.Young Red Dwarf Stripping away a Planet's Atmosphere
Illustration Credit: NASA, ESA, and D. Player (STScI)
Science: NASA, ESA, and P. Loyd and E. Shkolnik (Arizona State Univ)
NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT — HAbitable Zones and M dwarf Activity across Time.
"M dwarf" is the astronomical term for a red dwarf star — the smallest, most abundant, and longest-lived type of star in our galaxy. The HAZMAT program is an ultraviolet survey of red dwarfs at three different ages: young, intermediate, and old.
Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars. Hubble's ultraviolet sensitivity makes the telescope very valuable for observing these flares. The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere. When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.
The team has found that the flares from the youngest red dwarfs they surveyed—just about 40 million years old—are 100 to 1,000 times more energetic than when the stars are older. This younger age is when terrestrial planets are forming around their stars. ...
Astronomers Catch Red Dwarf Star in a Superflare Outburst
Arizona State University | 2018 Oct 18
HAZMAT. IV. Flares and Superflares on Young M Stars in the Far Ultraviolet ~ R.O. Parke Loyd et al
- arXiv.org > astro-ph > arXiv:1810.03277 > 08 Oct 2018