Characterizing and Mitigating Telluric Absorption in Precise Radial Velocities II: A Study of an M2 Type Star

TL;DR

This study quantifies how telluric absorption lines affect precise radial velocity measurements in M2 stars, revealing greater impact in the NIR compared to G stars, and compares simulations with real data from Barnard's star.

Contribution

It extends previous work by analyzing telluric effects on M dwarf stars, providing detailed bias estimates in RV measurements across spectral types and wavelengths.

Findings

M dwarf RVs are more affected by tellurics than G stars.

Tellurics can induce up to 16 cm/s errors in the red-optical and over 220 cm/s in the NIR for M dwarfs.

Comparison with Barnard's star data validates simulation results.

Abstract

Telluric absorption lines impact measuring precise radial velocities (RVs) from ground-based, high-resolution spectrographs. In this paper, we simulate the dependence of this impact on stellar spectral type and extend the work of the first paper in this series, which studied a G type star, to a synthetic M dwarf star. We quantify the bias in precise RV measurements in the visible and near-infrared (NIR) from the presence of tellurics in a simulated set of observations. We find that M dwarf RVs are more impacted by tellurics compared to G type stars. Specifically, for an M dwarf star, tellurics can induce RV errors of up to 16 cm/s in the red-optical and in excess of 220 cm/s in the NIR. For a G dwarf, comparable RV systematics are 3 cm/s in the red optical and 240 cm/s in the NIR. We attribute this relative increase for M dwarfs stars to the increased concordance in wavelength between telluric lines and stellar Doppler information content. We compare the results of our simulation to data collected on Barnard's star from the iSHELL spectrograph at the NASA Infrared Telescope Facility (IRTF). This study was conducted as a follow-up to the NASA probe mission concept study EarthFinder.