The Measured Impact of Chromatic Atmospheric Effects on Barycentric Corrections: Results from the EXtreme PREcision Spectrograph

Abstract

One source of error in high-precision radial velocity measurements of exoplanet host stars is chromatic change in Earth's atmospheric transmission during observations. Mitigation of this error requires that the photon-weighted barycentric correction be applied as a function of wavelength across the stellar spectrum. We have designed a system for chromatic photon-weighted barycentric corrections with the EXtreme PREcision Spectrograph (EXPRES) and present results from the first year of operations, based on radial velocity measurements of more than $10^3$ high-resolution stellar spectra. For observation times longer than 250 seconds, we find that if the chromatic component of the barycentric corrections is ignored, a range of radial velocity errors up to 1 m s${}^{-1}$ can be incurred with cross-correlation, depending on the nightly atmospheric conditions. For this distribution of errors, the standard deviation is 8.4 cm s${}^{-1}$ for G-type stars, 8.5 cm s${}^{-1}$ for K-type stars, and 2.1 cm s${}^{-1}$ for M-type stars. This error is reduced to well-below the instrumental and photon-noise limited floor by frequent flux sampling of the observed star with a low-resolution exposure meter spectrograph.

arXiv comment11 pages, 7 figures, accepted to AJ

References in corpus (25)

• Astropy: A Community Python Package for Astronomy
• The NumPy array: a structure for efficient numerical computation
• The Gaia mission
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Cosmic-Ray Rejection by Laplacian Edge Detection
• TEMPO2, a new pulsar timing package. I: Overview
• The CORALIE survey for southern extra-solar planets VII. Two short-period Saturnian companions to HD108147 and HD168746
• Planets and Stellar Activity: Hide and Seek in the CoRoT-7 system
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• The HARPS-TERRA project I. Description of the algorithms, performance and new measurements on a few remarkable stars observed by HARPS
• State of the Field: Extreme Precision Radial Velocities
• CHIRON - A Fiber Fed Spectrometer for Precise Radial Velocities
• CERES: A Set of Automated Routines for Echelle Spectra
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• Measuring precise radial velocities on individual spectral lines. I. Validation of the method and application to mitigate stellar activity
• EXPRES: A Next Generation RV Spectrograph in the Search for Earth-like Worlds
• Python Leap Second Management and Implementation of Precise Barycentric Correction (barycorrpy)
• A comprehensive radial velocity error budget for next generation Doppler spectrometers
• Synthesising, using, and correcting for telluric features in high-resolution astronomical spectra
• A Frequency Comb calibrated Solar Atlas
• Insights on the Spectral Signatures of Stellar Activity and Planets from PCA
• New Methods for Finding Activity-Sensitive Spectral Lines: Combined Visual Identification and an Automated Pipeline Find a Set of 40 Activity Indicators
• Towards a Self-calibrating, Empirical, Light-Weight Model for Tellurics in High-Resolution Spectra
• Modal Noise Mitigation through Fiber Agitation for Fiber-fed Radial Velocity Spectrographs
• Accounting for Chromatic Atmospheric Effects on Barycentric Corrections

Cited by in corpus (8)

• Performance Verification of the EXtreme PREcision Spectrograph
• High-resolution Transmission Spectroscopy of MASCARA-2 b with EXPRES
• An Extreme Precision Radial Velocity Pipeline: First Radial Velocities from EXPRES
• EXPRES I. HD~3651 an Ideal RV Benchmark
• Stable fiber-illumination for extremely precise radial velocities with NEID
• The impact of atmospheric dispersion in the performance of high-resolution spectrographs
• Photon-weighted barycentric correction and its importance for precise radial velocities
• On-sky measurements of atmospheric dispersion: II. Atmospheric models characterization