A comprehensive radial velocity error budget for next generation Doppler spectrometers

TL;DR

This paper develops a detailed error budget for the NEID spectrometer, identifying multiple noise sources affecting radial velocity measurements to guide the design of next-generation exoplanet detection instruments.

Contribution

It presents a comprehensive, adaptable error budget model combining simulations, measurements, and estimates to improve Doppler spectrometer precision for exoplanet discovery.

Findings

Identified key sources of systematic error in radial velocity measurements.

Constructed a modular error budget applicable to various spectrometers.

Provided insights for enhancing instrument design to reach Earth-like planet detection thresholds.

Abstract

We describe a detailed radial velocity error budget for the NASA-NSF Extreme Precision Doppler Spectrometer instrument concept NEID (NN-explore Exoplanet Investigations with Doppler spectroscopy). Such an instrument performance budget is a necessity for both identifying the variety of noise sources currently limiting Doppler measurements, and estimating the achievable performance of next generation exoplanet hunting Doppler spectrometers. For these instruments, no single source of instrumental error is expected to set the overall measurement floor. Rather, the overall instrumental measurement precision is set by the contribution of many individual error sources. We use a combination of numerical simulations, educated estimates based on published materials, extrapolations of physical models, results from laboratory measurements of spectroscopic subsystems, and informed upper limits for a variety of error sources to identify likely sources of systematic error and construct our global instrument performance error budget. While natively focused on the performance of the NEID instrument, this modular performance budget is immediately adaptable to a number of current and future instruments. Such an approach is an important step in charting a path towards improving Doppler measurement precisions to the levels necessary for discovering Earth-like planets.