Chia-Lung Lin (Graduate Institute of Astronomy, National Central University, Taoyuan 32001, Taiwan);Wen-Ping Chen (Graduate Institute of Astronomy, National Central University, Taoyuan 32001, Taiwan);Wing-Huen Ip (Graduate Institute of Astronomy, National Central University, Taoyuan 32001, Taiwan)
Wolf 359, a nearby M5.5 flare star, was observed by the EDEN project which is a global network of one-meter class telescopes for the purpose of identification and characterization of habitable exoplanets within 50 light-years. When compared with the archived K2 data, the flare frequency distribution of Wolf 359 can be extended to flare energies as low as 1028 ergs thus providing uniform information on the magnetic activity of this exoplanet-hosting M dwarf. We found that Wolf 359 has a relatively strong flare activity when compared to flaring M dwarfs in literature. The occurrence rate of flare with Ef >= 1028 ergs is about 5300 times per year. As a comparison, the Sun could produce such flare about 400 times per year in the solar maximum estimated in 2001. We also found that, according to flare activity - rotation period relation, Wolf 359 is in the saturation phase, indicating that its flare related emission (e.g. X-ray, UV flux, H-alpha, etc.) may be saturated as well.