On the Feasibility of Intense Radial Velocity Surveys for Earth-twin Discoveries

TL;DR

This paper evaluates the potential of next-generation high-precision Radial Velocity instruments, specifically the Terra Hunting Experiment with HARPS3, to detect Earth-twin exoplanets amidst stellar noise and observational challenges.

Contribution

It presents an end-to-end simulation framework demonstrating the feasibility and advantages of intense RV surveys for Earth-twin detection, comparing ground-based and space-based observation schedules.

Findings

Terra Hunting can detect Earth-twins in habitable zones.

It outperforms typical surveys in parameter accuracy.

It performs comparably to space-based schedules.

Abstract

This work assesses the potential capability of the next generation of high-precision Radial Velocity (RV) instruments for Earth-twin exoplanet detection. From the perspective of the importance of data sampling, the Terra Hunting Experiment aims to do this through an intense series of nightly RV observations over a long baseline on a carefully selected target list, via the brand-new instrument HARPS3. This paper describes an end-to-end simulation of generating and processing such data to help us better understand the impact of uncharacterised stellar noise in the recovery of Earth-mass planets with orbital periods of the order of many months. We consider full Keplerian systems, realistic simulated stellar noise, instrument white noise, and location-specific weather patterns for our observation schedules. We use Bayesian statistics to assess various planetary models fitted to the synthetic data, and compare the successful planet recovery of the Terra Hunting Experiment schedule with a typical reference survey. We find that the Terra Hunting Experiment can detect Earth-twins in the habitable zones of solar-type stars, in single and multi-planet systems, and in the presence of stellar signals. Also that it out-performs a typical reference survey on accuracy of recovered parameters, and that it performs comparably to an uninterrupted space-based schedule.