29 Oct 2019
Featured Publication: Giant Flares from Little Stars
The SkyMapper team has determined how often M dwarf stars, the most common and longest-lived stars in our galaxy, have energetic outbursts. These tiny, red stars often undergo giant flares that may impact the habitability of exoplanets around host stars such as TRAPPIST-1 or Proxima Centauri. The flares also show up in searches for other explosive events in the universe -- like supernova explosions, gamma-ray bursts, and kilonovae (the stellar collisions detected by gravitational-wave observatories).
The new discovery from this work is that the flaring fraction is nearly constant in the "Solar neighbourhood", regardless of the M dwarf temperature, with flares occurring in about 1 out of every 600 stars at any given time. Reassuringly for SkyMapper, the flares are much fainter in red light, so we have confidence that M dwarf flares will not confuse SkyMapper's search for kilonovae from gravitational-wave events, which uses light just beyond the red end of the visible spectrum.
"Photometric Flaring Fraction of M dwarf Stars from the SkyMapper Southern Survey" by Chang et al. has been published by the Monthly Notices of the Royal Astronomical Society.