Bibcode
Esposito, M.; González Hernández, J. I.; Rebolo, R.; Suárez Mascareño, A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 468, Issue 4, p.4772-4781
Advertised on:
7
2017
Citations
49
Refereed citations
45
Description
We investigate the activity-induced signals related to rotation and
magnetic cycles in late-type stars (FGKM) and analyse the Ca II H&K,
the H α and the radial velocity time series of 55 stars using the
spectra from the HARPS public data base and the light curves provided by
the All Sky Automated Survey. We search for short-term and long-term
periodic signals in the time series of activity indicators as well as in
the photometric light curves. Radial velocity data sets are then
analysed to determine the presence of activity-induced signals. We
measure a radial velocity signal induced by rotational modulation of
stellar surface features in 37 stars, from late-F-type to mid-M-type
stars. We report an empirical relationship, with some degree of spectral
type dependency, between the mean level of chromospheric emission
measured by the log _{10}(R^' }_{HK}) and the measured radial velocity
semi-amplitude. We also report a relationship between the semi-amplitude
of the chromospheric measured signal and the semi-amplitude of the
radial velocity-induced signal, which strongly depends on the spectral
type. We find that for a given strength of chromospheric activity (i.e.
a given rotation period), M-type stars tend to induce larger
rotation-related radial velocity signals than G- and K-type stars.