Abstract

For understanding the frequency of potentially habitable worlds and to constrain planet formation theories, it is critical to discover a sample of planetary systems that populate different regimes.

The NASA Kepler Mission has demonstrated that planets with 1 – 4 Earth radii are common around Sun-like stars. A chief objective of the HARPS -N Consortium is to measure accurately the masses and infer compositions for a sample of these small worlds. To study and characterise the planetary systems, we have at our disposal a sample of non-active and nearby G and K dwarfs through precise radial velocity measurements using HARPS -N.

HARPS -N is an ultra-stable fiber-fed high-resolution spectrograph installed on the TNG telescope at La Palma in the Canary Islands. I report on its performance during its first three years, and in particular the discovery of HD 219134 : the closest exoplanet system to the Sun containing a rocky planet.