Fundación Galileo Galilei - INAF Telescopio Nazionale Galileo 28°45'14.4N 17°53'20.6W 2387.2m A.S.L.

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The discovery of super-Earth GJ 685 b and the population of M-dwarf exoplanets

Speaker: Pinamonti, Matteo (INAF-Osservatorio Astrof. di Torino - Italia)

Date and time: 2020-01-09 11:30

Small rocky planets seem to be very abundant around low-mass M-type stars. Their actual planetary population is however not yet precisely understood, with several surveys aimed to expand the statistics with intensive detection campaigns, both photometric and spectroscopic. As part of the Harps-n red Dwarf Exoplanet Survey (HADES) pro- gramme, we combine spectroscopic and photometric measurements of the active M0-type star GJ 685 to accurately model the stellar rotation and disentangle its signals from genuine Doppler planetary signals. We detect a new low-mass extrasolar planet, GJ 685 b, with an orbital period of 24 days and a minimum mass roughly nine times the mass of the Earth. In the wake of this discovery, we also study the current sample of RV-detected M-dwarf planets, and present new statistical evidence of a difference in mass distribution between the populations of single- and multi-planet systems, which can shed new light on the formation mechanisms of low-mass planets around late-type stars.