Seminars at FGG
The HADES Program with HARPS-N@TNG
Speaker: Laura Affer (INAF - Oss. Astronomico di Palermo)
Date and time: 2025-02-07 11:30
We present the complete analysis of the Harps-n Dwarf Exoplanet Survey (HADES), which monitored the radial velocity variations of a large sample of M dwarfs, with HARPS-N@TNG, over the last 10 years, to determine the rate of occurrence of small planets around low-mass stars. M dwarfs are attractive targets for planet searches because they represent the shortest route to the detection of potentially habitable planets.We paid particular attention to radial velocity jitter levels induced by stellar activity, to rule out radial velocity variations due to astrophysical noise as Keplerian signals. In particular, the analysis of spectral indices based on Ca II H & K and Hα lines enables to highlight periods that are due to chromospheric inhomogeneities modulated by stellar rotation and differential rotation. The HADES (HARPS-N Red Dwarf Exoplanet Survey Radial Velocity) project is the result of a collaborative effort between the GAPS Consortium, the Institut de Ciències de l’Espai de Catalunya (ICE), and the Instituto de Astrofísica de Canarias (IAC). The targets were selected in a narrow range of spectral types from M0 to M3, in order to study the planetary population around a well-defined class of host stars. Two photometric programs regularly and almost simultaneously follow-up the sample of M stars to characterize the stellar activity, to provide an estimate of the stellar rotation periods by detecting periodic modulation in the differential light curves and thus to distinguish from the periodic signals those due to activity and to the presence of planetary companions. The HADES collaboration has already produced remarkable results, both concerning the statistical, activity and characterization part and the planet revealing part of M stars.