New research explores how super flares affect planets' habitability
Largest ever sample of super flares

Date:
October 7, 2020
Source:
University of North Carolina at Chapel Hill
Summary:
New research will help astrobiologists understand how much radiation
planets experience during super flares and whether life could
exist on worlds beyond our solar system.



FULL STORY ========================================================================== Ultraviolet light from giant stellar flares can destroy a planet's habitability. New research from the University of North Carolina at
Chapel Hill will help astrobiologists understand how much radiation
planets experience during super flares and whether life could exist on
worlds beyond our solar system.


========================================================================== Super flares are bursts of energy that are 10 to 1,000 times larger
than the biggest flares from the Earth's sun. These flares can bathe a
planet in an amount of ultraviolet light huge enough to doom the chances
of life surviving there.

Researchers from UNC-Chapel Hill have for the first time measured the temperature of a large sample of super flares from stars, and the flares' likely ultraviolet emissions. Their findings, published Oct. 5 ahead of
print in Astrophysical Journal, will allow researchers to put limits on
the habitability of planets that are targets of upcoming planet-finding missions.

"We found planets orbiting young stars may experience life-prohibiting
levels of UV radiation, although some micro-organisms might survive," said
lead study author Ward S. Howard, a doctoral student in the Department
of Physics and Astronomy at UNC-Chapel Hill.

Howard and colleagues at UNC-Chapel Hill used the UNC-Chapel Hill
Evryscope telescope array and NASA's Transiting Exoplanet Survey Satellite (TESS) to simultaneously observe the largest sample of super flares.

The team's research expands upon previous work that has largely focused on flare temperatures and radiation from only a handful of super flares from
a few stars. In expanding the research, the team discovered a statistical relationship between the size of a super flare and its temperature. The temperature predicts the amount of radiation that potentially precludes
on- surface life.

Super flares typically emit most of their UV radiation during a rapid
peak lasting only five to 15 minutes. The simultaneous Evryscope and TESS observations were obtained at two-minute intervals, ensuring multiple measurements were taken during the peak of each super flare.

This is the first time the temperatures of such a large sample of super
flares has ever been studied. The frequency of observations allowed
the team to discover the amount of time super flares can cook orbiting
planets with intense UV radiation.

The flares observed have already informed the TESS Extended Mission to
discover thousands of exoplanets in orbit around the brightest dwarf
stars in the sky.

TESS is now targeting high priority flare stars from the UNC-Chapel Hill
sample for more frequent observations.

"Longer term these results may inform the choice of planetary systems to
be observed by NASA's James Webb Space Telescope based on the system's
flaring activity," said study co-author Nicholas M. Law, associate
professor of physics and astronomy at UNC-Chapel Hill and principal investigator of the Evryscope telescope.


========================================================================== Story Source: Materials provided by University_of_North_Carolina_at_Chapel_Hill. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Ward S. Howard, Hank Corbett, Nicholas M. Law, Jeffrey K. Ratzloff,
Nathan Galliher, Amy L. Glazier, Ramses Gonzalez, Alan Vasquez
Soto, Octavi Fors, Daniel del Ser, Joshua Haislip. EvryFlare
III: Temperature Evolution and Habitability Impacts of Dozens
of Superflares Observed Simultaneously by Evryscope and
TESS. Astrophysical Journal, 2020 [abstract] ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201007123037.htm

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