Triggers:Flares

Statistical study of M dwarf flares in Stripe 82 is presented in Kowalski et al. 2009.

• Colour range for M-dwarfs (r − i) > 0.53 and (i − z) > 0.3 and (u-r) > 3
• The most flaring are late type M-dwarfs (M4-M6), earlier types (M2-M3) flare half as often as late types and M0-M1 dwarfs flare only 20% as often as late types.
• flares are the most pronounced in u-band
• around 35% of M-dwarfs are in binary systems - these have bluer u-g. Most single M-dwarfs will have u-g > 1.8
• g - K > 4
• amplitude in u > 0.7 mag up to 5 mag.
• large and small flares possible
• flaring fraction: 0.0108%, i.e. 1 of every 10,000 observation of a M-dwarf in Stripe 82 resulted in a flare
• 1.3 flares per hour sq.deg with <math>\Delta u > 0.7</math> mag, with slightly more flares towards the galactic plane.

Example of flares in Gl234AB (V577 Mon) from Doyle et al. 1989

Example flare detected by Pi of the Sky project. From Sokolowski 2008.

High temporal resolution observations of a flare star by Pi of the Sky. From Sokolowski 2008.