A Hermite-Gaussian Based Radial Velocity Estimation Method
arXiv:2005.14083
Abstract
As the first successful technique used to detect exoplanets orbiting distant stars, the Radial Velocity Method aims to detect a periodic Doppler shift in a star's spectrum. We introduce a new, mathematically rigorous, approach to detect such a signal that accounts for functional relationships of neighboring wavelengths, minimizes the role of wavelength interpolation, accounts for heteroskedastic noise, and easily allows for statistical inference. Using Hermite-Gaussian functions, we show that the problem of detecting a Doppler shift in the spectrum can be reduced to linear regression in many settings. A simulation study demonstrates that the proposed method is able to accurately estimate an individual spectrum's radial velocity with precision below 0.3 m/s. Furthermore, the new method outperforms the traditional Cross-Correlation Function approach by reducing the root mean squared error up to 15 cm/s. The proposed method is also demonstrated on a new set of observations from the EXtreme PREcision Spectrometer (EXPRES) for the star 51 Pegasi, and successfully recovers estimates that agree well with previous studies of this planetary system. Data and Python3 code associated with this work can be found at https://github.com/parkerholzer/hgrv_method. The method is also implemented in the open source R package rvmethod.
arXiv comment48 pages, 19 figures
References in corpus (15)
- The NASA Exoplanet Archive: Data and Tools for Exoplanet Research
- Chromospheric Activity and Jitter Measurements for 2630 Stars on the California Planet Search
- A Gaussian process framework for modelling stellar activity signals in radial velocity data
- An extrasolar planetary system with three Neptune-mass planets
- State of the Field: Extreme Precision Radial Velocities
- The HARPS survey for southern extra-solar planets II. A 14 Earth-masses exoplanet around mu Arae
- EXPRES: A Next Generation RV Spectrograph in the Search for Earth-like Worlds
- Habitable-zone super-Earth candidate in a six-planet system around the K2.5V star HD 40307
- Performance Verification of the EXtreme PREcision Spectrograph
- Insights on the Spectral Signatures of Stellar Activity and Planets from PCA
- Introducing EMILI: Computer Aided Emission Line Identification
- A robust, template-free approach to precise radial velocity extraction
- Towards a Self-calibrating, Empirical, Light-Weight Model for Tellurics in High-Resolution Spectra
- On the Interpolation of Model Atmospheres and High-Resolution Synthetic Stellar Spectra
- Identifying MgII Narrow Absorption Lines with Deep Learning