Applications of a Gaussian Process Framework for Modelling of High-Resolution Exoplanet Spectra

Abstract

Observations of exoplanet atmospheres in high resolution have the potential to resolve individual planetary absorption lines, despite the issues associated with ground-based observations. The removal of contaminating stellar and telluric absorption features is one of the most sensitive steps required to reveal the planetary spectrum and, while many different detrending methods exist, it remains difficult to directly compare the performance and efficacy of these methods. Additionally, though the standard cross-correlation method enables robust detection of specific atmospheric species, it only probes for features that are expected a priori. Here we present a novel methodology using Gaussian process (GP) regression to directly model the components of high-resolution spectra, which partially addresses these issues. We use two archival CRIRES/VLT data sets as test cases, observations of the hot Jupiters HD 189733 b and 51 Pegasi b, recovering injected signals with average line contrast ratios of $\sim 4.37\times 10^{-3}$ and $\sim 1.39\times 10^{-3}$, and planet radial velocities $\Delta K_{\mathrm{p}}=1.45\pm 1.53\mathrm{km}{\mathrm{s}}^{-1}$ and $\Delta K_{\mathrm{p}}=0.12\pm 0.12\mathrm{km}{\mathrm{s}}^{-1}$ from the injection velocities respectively. In addition, we demonstrate an application of the GP method to assess the impact of the detrending process on the planetary spectrum, by implementing injection-recovery tests. We show that standard detrending methods used in the literature negatively affect the amplitudes of absorption features in particular, which has the potential to render retrieval analyses inaccurate. Finally, we discuss possible limiting factors for the non-detections using this method, likely to be remedied by higher signal-to-noise data.

arXiv comment14 pages, 7 figures, 3 tables. Accepted for publication in MNRAS

References in corpus (61)

• emcee: The MCMC Hammer
• A new extensive library of PHOENIX stellar atmospheres and synthetic spectra
• Fast and scalable Gaussian process modeling with applications to astronomical time series
• The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• A Temperature and Abundance Retrieval Method for Exoplanet Atmospheres
• Correcting systematic effects in a large set of photometric lightcurves
• ELODIE metallicity-biased search for transiting Hot Jupiters II. A very hot Jupiter transiting the bright K star HD189733
• The signature of orbital motion from the dayside of the planet tau Bootis b
• A Gaussian process framework for modelling stellar activity signals in radial velocity data
• Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 microns
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Nightside condensation of iron in an ultra-hot giant exoplanet
• An atmospheric radiation model for Cerro Paranal. I. The optical spectral range
• A Gaussian process framework for modelling instrumental systematics: application to transmission spectroscopy
• Retrieving Temperatures and Abundances of Exoplanet Atmospheres with High-Resolution Cross-Correlation Spectroscopy
• Inferring probabilistic stellar rotation periods using Gaussian processes
• Detection of carbon monoxide in the high-resolution day-side spectrum of the exoplanet HD 189733b
• An accurate, extensive, and practical line list of methane for the HITEMP database
• Detection of Fe I in the atmosphere of the ultra-hot Jupiter WASP-121b, and a new likelihood-based approach for Doppler-resolved spectroscopy
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• The Rossiter-McLaughlin effect of CoRoT-3b & HD189733b
• K2SC: Flexible systematics correction and detrending of K2 light curves using Gaussian Process regression
• A solar C/O and sub-solar metallicity in a hot Jupiter atmosphere
• Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere
• Atmospheric characterization of the ultra-hot Jupiter MASCARA-2b/KELT-20b
• Carbon monoxide and water vapor in the atmosphere of the non-transiting exoplanet HD 179949 b
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) IV. A spectral inventory of atoms and molecules in the high-resolution transmission spectrum of WASP-121 b
• High-Resolution Spectroscopic Detection of TiO and Stratosphere in the Day-side of WASP-33b
• Weighing The Non-Transiting Hot Jupiter Tau BOO b
• Detection of molecular absorption in the dayside of exoplanet 51 Pegasi b?
• Correcting for Telluric Absorption: Methods, Case Studies, and Release of the TelFit Code
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• Neutral Iron Emission Lines From The Day-side Of KELT-9b -- The GAPS Programme With HARPS-N At TNG XX
• Python Leap Second Management and Implementation of Precise Barycentric Correction (barycorrpy)
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121b
• Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs
• The High-Resolution Transmission Spectrum of HD 189733b Interpreted with Atmospheric Doppler Shifts from Three-Dimensional General Circulation Models
• On the robustness of analysis techniques for molecular detections using high resolution exoplanet spectroscopy
• Decomposing the Iron Cross-Correlation Signal of the Ultra-Hot Jupiter WASP-76b in Transmission using 3D Monte-Carlo Radiative Transfer
• The slow spin of the young sub-stellar companion GQ Lupi b and its orbital configuration
• Ground-based detection of Calcium and possibly Scandium and Hydrogen in the atmosphere of HD 209458b
• Non-detection of TiO and VO in the atmosphere of WASP-121b using high-resolution spectroscopy
• Evidence against a strong thermal inversion in HD 209458 b from high-dispersion spectroscopy
• The Earth as an extrasolar transiting planet: Earth's atmospheric composition and thickness revealed by Lunar eclipse observations
• A Significant Increase in Detection of High-Resolution Emission Spectra Using a Three-Dimensional Atmospheric Model of a Hot Jupiter
• Detection of Fe\,{\sc i} Emission in the Day-side Spectrum of WASP-33b
• Ground- and Space-based Detection of the Thermal Emission Spectrum of the Transiting Hot Jupiter KELT-2Ab
• Disentangling Time Series Spectra with Gaussian Processes: Applications to Radial Velocity Analysis
• On the Eccentricity Distribution of Short-Period Single-Planet Systems
• Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b
• Exoplanet Atmospheres at High Spectral Resolution
• Detection of Water Vapor in the Thermal Spectrum of the Non-Transiting Hot Jupiter upsilon Andromedae b
• A Search for FeH in Hot-Jupiter Atmospheres with High-Dispersion Spectroscopy
• Is TiO emission present in the ultra-hot Jupiter WASP-33b? A reassessment using the improved ExoMol Toto line list
• A robust, template-free approach to precise radial velocity extraction
• Planet and star synergy at high spectral resolution. A rationale for the characterisation of exoplanet atmospheres. I. The Infrared
• A weak spectral signature of water vapour in the atmosphere of HD 179949 b at high spectral resolution in the L-band
• A Fast, 2D Gaussian Process Method Based on Celerite: Applications to Transiting Exoplanet Discovery and Characterization
• Assessing telluric correction methods for Na detections with high-resolution exoplanet transmission spectroscopy
• The GAPS Programme at TNG. XXIX. No detection of reflected light from 51 Peg b using optical high-resolution spectroscopy

Cited by in corpus (3)

• Transmission spectroscopy of the lowest-density gas giant: metals and a potential extended outflow in HAT-P-67b
• Enabling Robust Exoplanet Atmospheric Retrievals with Gaussian Processes
• How do wavelength correlations affect transmission spectra? Application of a new fast and flexible 2D Gaussian process framework to transiting exoplanet spectroscopy