Flaring Antics from Our Stellar Neighbor

Editor’s note: AAS Nova is on vacation until 22 September. Normal posting will resume at that time; in the meantime, we’ll be taking this opportunity to look at a few interesting AAS journal articles that have recently been in the news or drawn attention.

Astronomers have observed the largest stellar flare ever recorded from Proxima Centauri, our nearest stellar neighbor. Detected in May 2019, the flare was recently reported in a publication led by scientist Meredith MacGregor (University of Colorado Boulder). During the flare, MacGregor and collaborators observed Proxima Centauri to brighten by a factor of more than 1,000 in millimeter emission, and by a factor of more than 14,000 in ultraviolet emission.

Studying the combination of these flare signals helps us to better understand what triggers these powerful flashes and how they evolve. This, in turn, provides valuable information about the radiation environment surrounding rocky, inner planets — planets like Proxima Centauri b, which lies in Proxima Centauri’s habitable zone but may be at risk of being cooked by bright and energetic flares from its host.

Original article: “Discovery of an Extremely Short Duration Flare from Proxima Centauri Using Millimeter through Far-ultraviolet Observations,” Meredith A. MacGregor et al 2021 ApJL 911 L25. doi:10.3847/2041-8213/abf14c
University of Colorado Boulder press release: Humongous flare from sun’s nearest neighbor breaks records