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 about 1700 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 violent mega-flares. 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.


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Last modified: Mon Oct 22 17:38:38 CEST 2012 by S. Wedemeyer