INTERNATIONAL TEAM - MAGNETIC ACTIVITY OF DWARF STARS AND
HABITABILITY OF EXTRA-SOLAR PLANETS
In 2012, the
International Space Science Institute
(ISSI) in Bern, Switzerland granted my proposal for an
international team to investigate the
"Magnetic Activity of M-type Dwarf Stars and the Influence on Habitable Extra-solar Planets".
The team consists of 17 scientists from across Europe, the USA, and
Mexico, with complementary expertise in observing magnetic fields and
flares on the Sun and other cool stars, in numerical modelling of cool
stellar and planetary atmospheres, habitability of extra-solar
planets, and astrobiology.
As of today, we know more than 800 confirmed planets that orbit other
stars outside our solar system.
About 80 % of all stars in our galaxy are red dwarf stars of spectral
type M (also referred to as M-dwarfs).
These stars are much cooler, fainter, and smaller than our Sun.
Their large number, however, makes it likely that they are by far the
most common hosts of extra-solar planets.
There is only a big potential problem with these host stars:
Many M-dwarfs are known to exhibit high levels of magnetic activity and
Flares are intense bursts of radiation and highly energetic particles
that occur in the layers above the surface of a star.
Such outbursts occur on our Sun, too, and lead in connection with
coronal mass ejections to polar lights on Earth and -- in the worst
case -- to problems with satellites or even power grids on the ground.
Mega-flares on M-dwarfs, however, can be a thousand times stronger
than their solar analogues.
Moreover, a potentially habitable planet has to be rather close to its
cool host star compared to the much hotter Sun.
Consequently, these energetic outbursts can have a potentially
hazardous impact on accompanying nearby planets.
It is not clear yet if and how the conditions for life to form and
exist are influenced and if an otherwise habitable world would be
turned into a hostile environment.
The selected team of experts will meet in Bern to discuss how to investigate these
questions which are crucial for understanding under which conditions
life may evolve.
Last modified: Mon Oct 22 17:38:38 CEST 2012
by S. Wedemeyer