Stellar variability in radial velocity

Abstract

Stellar activity due to different processes (magnetic activity, photospheric flows) affects the measurement of radial velocities (RV). Radial velocities have been widely used to detect exoplanets, although the stellar signal significantly impacts the detection and characterisation performance, especially for low mass planets. On the other hand, RV time series are also very rich in information on stellar processes. In this lecture, I review the context of RV observations, describe how radial velocities are measured, and the properties of typical observations. I present the challenges represented by stellar activity for exoplanet studies, and describe the processes at play. Finally, I review the approaches which have been developed, including observations and simulations, as well as solar and stellar comparisons.

Lecture made in September 2019, to be published in the Proceedings of the Evry Schatzman School 2019 "Interactions star-planet". EDP, Eds Bigot, Bouvier, Lebreton, Chiavassa

Cited by in corpus (4)

• Mitigating stellar activity jitter with different line lists for least-squares deconvolution: analysis of a parametric and a randomised line selection
• Predicting convective blueshift and radial-velocity dispersion due to granulation for FGK stars
• Astrometric radial velocities for nearby stars
• Simulating starspot activity jitter for spectral types F--M: realistic estimates for a representative sample of known exoplanet hosts