5 M dwarfs radial velocity curves

Over the last 13 years, precise radial velocities measured with the HARPS spectrograph have identified over a dozen super-Earths and Earth-mass planets (msini<=10M_{sun}_) around M dwarfs, with a well understood selection function. This well defined sample informs on their frequency of occurrence and on the distribution of their orbital parameters, and therefore already constrains our understanding of planetary formation.

The subset of these low-mass planets that were found within the habitable zone of their host star also provide prized targets for future atmospheric biomarkers searches. We are working to extend this planetary sample to lower masses and longer periods through dense and long-term monitoring of the radial velocity of a small M dwarf sample. We obtained large numbers of HARPS spectra for the M dwarfs GJ 3138, GJ 3323, GJ 273, GJ 628 and GJ 3293, from which we derived radial velocities (RVs) and spectroscopic activity indicators.