Modeling the RV and BVS of active stars

TL;DR

This paper introduces a novel method for modeling radial velocity data of active stars by jointly fitting planetary signals and stellar activity effects using BVS correlations, improving planet detection accuracy.

Contribution

The paper presents a new approach that models RV and BVS simultaneously, accounting for stellar activity directly during planetary signal fitting.

Findings

Method effectively distinguishes planetary signals from stellar activity.

Compared to existing algorithms, the approach shows improved accuracy on simulated data.

The joint modeling approach offers a promising tool for active star planet searches.

Abstract

We present a method of modeling the radial velocity (RV) measurements which can be useful in searching for planets hosted by chromospherically active stars. We assume that the observed RV signal is induced by the reflex motion of a star as well as by distortions of spectral line profiles, measured by the Bisector Velocity Span (BVS). The RVs are fitted with a common planetary model including RV correction term depending linearly on the BVS, which accounts for the stellar activity. The coefficient of correlation is an additional free parameter of the RV model. That approach differs from correcting the RVs before or after fitting the "pure" planetary model. We test the method on simulated data derived for single-planet systems. The results are compared with the outcomes of algorithms found in the literature.