The Extreme Stellar-Signals Project III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID
Abstract
We present an analysis of Sun-as-a-star observations from four different high-resolution, stabilized spectrographs -- HARPS, HARPS-N, EXPRES, and NEID. With simultaneous observations of the Sun from four different instruments, we are able to gain insight into the radial velocity precision and accuracy delivered by each of these instruments and isolate instrumental systematics that differ from true astrophysical signals. With solar observations, we can completely characterize the expected Doppler shift contributed by orbiting Solar System bodies and remove them. This results in a data set with measured velocity variations that purely trace flows on the solar surface. Direct comparisons of the radial velocities measured by each instrument show remarkable agreement with residual intra-day scatter of only 15-30 cm/s. This shows that current ultra-stabilized instruments have broken through to a new level of measurement precision that reveals stellar variability with high fidelity and detail. We end by discussing how radial velocities from different instruments can be combined to provide powerful leverage for testing techniques to mitigate stellar signals.
Keywords
Cite
@article{arxiv.2309.03762,
title = {The Extreme Stellar-Signals Project III. Combining Solar Data from HARPS, HARPS-N, EXPRES, and NEID},
author = {Lily L. Zhao and Xavier Dumusque and Eric B. Ford and Joe Llama and Annelies Mortier and Megan Bedell and Khaled Al Moulla and Chad F. Bender and Cullen H. Blake and John M. Brewer and Andrew Collier Cameron and Rosario Cosentino and Pedro Figueira and Debra A. Fischer and Adriano Ghedina and Manuel Gonzalez and Samuel Halverson and Shubham Kanodia and David W. Latham and Andrea S. J. Lin and Gaspare Lo Curto and Marcello Lodi and Sarah E. Logsdon and Christophe Lovis and Suvrath Mahadevan and Andrew Monson and Joe P. Ninan and Francesco Pepe and Rachael M. Roettenbacher and Arpita Roy and Nuno C. Santos and Christian Schwab and Guðmundur Stefánsson and Andrew E. Szymkowiak and Ryan C. Terrien and Stephane Udry and Sam A. Weiss and François Wildi and Thibault Wildi and Jason T. Wright},
journal= {arXiv preprint arXiv:2309.03762},
year = {2023}
}
Comments
17 pages, 9 figures, accepted for publication