Planets around young active Solar-type stars: Assessing detection capabilities from a non stabilised spectrograph

TL;DR

This study evaluates the ability to detect close-in gas giant exoplanets around young active stars using non-stabilized spectrograph data, demonstrating the effectiveness of Gaussian Processes in overcoming stellar activity noise.

Contribution

It introduces a method combining Doppler Imaging and Gaussian Processes to detect Hot Jupiters in legacy data from non-stabilized spectrographs, highlighting the potential for new discoveries.

Findings

Gaussian Processes improve detection sensitivity amidst stellar activity

Hot Jupiters with semi-amplitude of 100 m/s can be confidently detected

The approach enables identification of candidates in existing datasets

Abstract

Short-orbit gas giant planet formation/evolution mechanisms are still not well understood. One promising pathway to discriminate between mechanisms is to constrain the occurrence rate of these peculiar exoplanets at the earliest stage of the system's life. However, a major limitation when studying newly born stars is stellar activity. This cocktail of phenomena triggered by fast rotation, strong magnetic fields and complex internal dynamics, especially present in very young stars, compromises our ability to detect exoplanets. In this paper, we investigated the limitations of such detections in the context of already acquired data solely using radial velocity data acquired with a non-stabilised spectrograph. We employed two strategies: Doppler Imaging and Gaussian Processes and could confidently detect Hot Jupiters with semi-amplitude of 100 $m.s^{-1}$ buried in the stellar activity. We also showed the advantages of the Gaussian Process approach in this case. This study serves as a proof of concept to identify potential candidates for follow-up observations or even discover such planets in legacy datasets available to the community.