HKalpha Project: Long-term activity in dM stars

BUCCINO, A. P.

Workshop; ExoAr I: ¨1st. Argentinian Workshop on Exoplanets Observations and data analysis"; 2017

Over the last decade, new interest in M dwarfs has emerged. Theyare prime targets for current and upcoming exoplanet searches andcharacterization efforts, due to their ubiquity in the solarneighborhood and high occurrence rates of small exoplanets in thehabitable zone. However, these stars can be very active and theiractivity signatures can hinder the detection of orbitingplanets. Furthermore, levels of UV radiation, which are stronglyrelated to stellar activity, can also limit the habitability.Since 1999, the HKα Porject is operating in the Argentinianobservatory CASLEO (Complejo Astronómico El Leoncito). Wesystematically observe more than 150 main-sequence stars from F3to M5.5. To date, we have more than 5000 mid-resolution spectra,ranging from 389 to 669 nm, which constitute an ideal dataset tostudy long-term activity. First, I show the first evidences ofcyclic activity for the fully-convective M5.5Ve star ProximaCentauri, for three mid-M (e.g. AD Leonis) and two early-M starsalready reported by our group. Then, I present the first analysisof activity of a set of newly identified M stars newly, alreadyinluded in different surveys (CARMENES, NGTS, etc.).