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Gavin Ramsay
Armagh Observatory
College Hill
Armagh
N Ireland
BT61 9DG
gar@arm.ac.uk
+44 028 3751 2951

Flare Stars

Flares stars like the one described in our study (which has a mass around 1/4 of that of the Sun) have been studied for many decades. However, with the Kepler satellite, observations of stars lasting up to 4 years with very few interuptions were made. From the Earth, observations are uninterupted during the day and the times of year when the star gets too close to the Sun. The Kepler observations allowed astronomers to determine how the flare characteristics (the number, duration, energy) are effected by a stars mass, rotation period and age.

Flares of different energies and duration are regularly seen from the Sun with energies ranging from optical light to X-rays. We know that the Sun's activity varies on a dozen year timescale. By observing the flare characteristics of stars with different mass, age and rotation period we can gain insight to what really powers flares from stars.

We know that flares from the Sun can effect human activities on the Earth. (Think of the huge disruption to the electric grid in Canada in 1989). If a planet is close to a star which has lots of low energy flares, the effect could be much greater, and even prevent the formation of life on that exo-planet.

We have recently obtained data of some flare stars using Kepler in the next phase of its life. Last year Kepler lost the second of its 4 gyroscopes which meant it had difficultly in keeping its telescope pointing at the same patch of sky with the accuracy needed. Now K2 (as its called) will look at different fields for approximately 75 days along the ecliptic plane - the track the Sun follows during the year.

Below is 4 days worth of Kepler data on the M4 star KIC9726699.