A team of astronomers has used the High Dispersion Spectrograph on the Subaru Telescope to conduct spectroscopic observations of Sun-like "superflare" stars first observed and cataloged by the Kepler Space Telescope. The investigations focused on the detailed properties of these stars and confirmed that Sun-like stars with large starspots can experience superflares.
The team targeted a set of solar-type stars emitting very large flares that release total energies 10-10000 times greater than the biggest solar flares.
This work follows up on observations made in 2012 (Maehara et al. Nature on 2012 May 24), where the team reported finding several hundred superflares on solar-type stars by analyzing stellar observation data from Kepler Space Telescope. This discovery was very important since it enabled the astronomers to conduct statistical analysis of superflares for the first time. However, more detailed observations were needed to investigate detailed properties of superflare stars and whether such massive flares can occur on ordinary single stars similar to our Sun.