Stellar activity mitigation in radial velocity measurements

Florian Lienhard (ETH Zurich) Cambridge Fluids Network - fluids-related seminars 30 April 2024 1:00pm Battcock coffee area + ONLINE - Details to be sent by email Over the past decades, the radial velocity (RV) community has made tremendous leaps forward in detecting and characterising ever smaller and lighter exoplanets. This trend has been interrupted in recent years, as planetary RV signals below 1 m/s are drowned out by the stars’ activity. The detection of Earth analogues producing an RV effect of about 10 cm/s is therefore currently out of reach. Several avenues are being explored to restore the trend towards the detection of increasingly less massive planets. These include improvements in (1) instruments, (2) observing strategies, (3) RV extraction techniques, (4) stellar activity monitoring, and (5) stellar activity modelling. In this talk, I will focus on points (4), and (5). I will provide an overview of stellar activity mitigation techniques and show how a proxy for stellar magnetic activity induced RV variations can be extracted from intensity spectra in the visible wavelength range, providing an independent estimate of the evolution of the magnetic field.