EXPRES I. HD~3651 an Ideal RV Benchmark

Abstract

The next generation of exoplanet-hunting spectrographs should deliver up to an order of magnitude improvement in radial velocity precision over the standard 1 m/s state of the art. This advance is critical for enabling the detection of Earth-mass planets around Sun-like stars. New calibration techniques such as laser frequency combs and stabilized etalons ensure that the instrumental stability is well characterized. However, additional sources of error include stellar noise, undetected short-period planets, and telluric contamination. To understand and ultimately mitigate error sources, the contributing terms in the error budget must be isolated to the greatest extent possible. Here, we introduce a new high cadence radial velocity program, the EXPRES 100 Earths program, which aims to identify rocky planets around bright, nearby G and K dwarfs. We also present a benchmark case: the 62-d orbit of a Saturn-mass planet orbiting the chromospherically quiet star, HD 3651. The combination of high eccentricity (0.6) and a moderately long orbital period, ensures significant dynamical clearing of any inner planets. Our Keplerian model for this planetary orbit has a residual RMS of 58 cm/s over a $\sim 6$ month time baseline. By eliminating significant contributors to the radial velocity error budget, HD 3651 serves as a standard for evaluating the long term precision of extreme precision radial velocity (EPRV) programs.

11 pages, 6 figures, accepted for publication in Astronomical Journal

References in corpus (8)

• The Transiting Exoplanet Survey Satellite
• Efficient fitting of multiplanet Keplerian models to radial velocity and astrometry data
• Hybrid Symplectic Integrators for Planetary Dynamics
• Filtering solar-like oscillations for exoplanet detection in radial velocity observations
• Towards a Self-calibrating, Empirical, Light-Weight Model for Tellurics in High-Resolution Spectra
• Accounting for Chromatic Atmospheric Effects on Barycentric Corrections
• Radial-velocity jitter of stars as a function of observational timescale and stellar age
• The Measured Impact of Chromatic Atmospheric Effects on Barycentric Corrections: Results from the EXtreme PREcision Spectrograph

Cited by in corpus (11)

• The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
• Statistical methods for exoplanet detection with radial velocities
• YARARA V2: Reaching sub m/s precision over a decade using PCA on line-by-line RVs
• Stellar activity correction using PCA decomposition of shells
• Doppler Constraints on Planetary Companions to Nearby Sun-like Stars: An Archival Radial Velocity Survey of Southern Targets for Proposed NASA Direct Imaging Missions
• MAROON-X: The first two years of EPRVs from Gemini North
• SOAP-GPU: Efficient Spectral Modelling of Stellar Activity Using Graphical Processing Units
• Excalibur: A Non-Parametric, Hierarchical Wavelength-Calibration Method for a Precision Spectrograph
• EXPRES. II. Searching for Planets Around Active Stars: A Case Study of HD 101501
• Revised Properties and Dynamical History for the HD 17156 System
• TOI-1518b: A Misaligned Ultra-hot Jupiter with Iron in its Atmosphere