Ground-Based Radial Velocity as Critical Support for Future NASA Earth-Finding Missions

TL;DR

Future space missions searching for biosignatures will greatly benefit from ground-based radial velocity surveys that can detect small signals, improve scheduling, reduce false positives, and provide essential mass data for interpreting planetary atmospheres.

Contribution

This paper highlights the critical role of ground-based radial velocity surveys in supporting future NASA Earth-finding missions by enhancing detection, scheduling, and interpretation capabilities.

Findings

RV surveys can detect Earth-mass planets around nearby stars.

RV data reduces the number of revisits needed for orbit determination.

Mass measurements from RVs aid in interpreting atmospheric biosignatures.

Abstract

Future space-based direct imaging missions are poised to search for biosignatures in the atmospheres of potentially habitable planets orbiting nearby AFGKM stars. Although these missions could conduct a survey of high-priority target stars to detect candidate Earth-like planets, conducting a precursor radial velocity (RV) survey will benefit future direct imaging missions in four ways. First, an RV survey capable of detecting signals as small as 8 cm/s over timescales of a few years could discover potentially habitable Earth-mass planets orbiting dozens of nearby GKM stars accessible to space-based direct imaging. Second, RVs will improve scheduling efficiency by reducing the required number of revisits for orbit determination, and revealing when a planet of interest is most observable. Third, RV observations will reveal the masses of gas and ice giants that could be mistaken for Earth-mass planets, thereby reducing the time spent identifying false positives. Fourth, mass measurements from RVs will provide the surface gravities necessary for interpreting atmospheric spectra and potential biosignatures.