Seeing above the Clouds with High Resolution Spectroscopy

Abstract

In the last decade ground based high resolution Doppler spectroscopy (HRS) has detected numerous species in transiting and non-transiting hot Jupiters, and is ideally placed for atmospheric characterisation of warm Neptunes and super Earths. Many of these cooler and smaller exoplanets have shown cloudy atmospheres from low resolution near infrared observations, making constraints on chemical species difficult. We investigate how HRS can improve on these given its sensitivity to spectral line cores which probe higher altitudes above the clouds. We model transmission spectra for the warm Neptune GJ~3470~b and determine the detectability of H${}_2$O with the CARMENES, GIANO and SPIRou spectrographs. We also model a grid of spectra for another warm Neptune, GJ~436~b, over a range of cloud-top pressure and H${}_2$O abundance. We show H${}_2$O is detectable for both planets with modest observational time and that the high H${}_2$O abundance-high cloud deck degeneracy is broken with HRS. However, meaningful constraints on abundance and cloud-top pressure are only possible in the high metallicity scenario. We also show that detections of CH${}_4$ and NH${}_3$ are possible from cloudy models of GJ~436~b. Lastly, we show how the presence of the Earth's transmission spectrum hinders the detection of H${}_2$O for the most cloudy scenarios given that telluric absorption overlaps with the strongest H${}_2$O features. The constraints possible with HRS on the molecular species can be used for compositional analysis and to study the chemical diversity of such planets in the future.

13 pages, 9 figures, accepted for publication in MNRAS, Posting of this manuscript on the arXiv was coordinated with C. Hood et al

References in corpus (33)

• The Transiting Exoplanet Survey Satellite
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• A Precise Water Abundance Measurement for the Hot Jupiter WASP-43b
• Rayleigh scattering in the transit spectrum of HD 189733b
• Water Vapor in the Spectrum of the Extrasolar Planet HD 189733b: 1. the Transit
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b
• How to Characterize Habitable Worlds and Signs of Life
• ExoMol molecular line lists XXXV: a rotation-vibration line list for hot ammonia
• A Sub-Neptune Exoplanet with a Low-Metallicity Methane-Depleted Atmosphere and Mie-Scattering Clouds
• A spectral survey of an ultra-hot Jupiter: Detection of metals in the transmission spectrum of KELT-9 b
• HAT-P-26b: A Neptune-Mass Exoplanet with a Well Constrained Heavy Element Abundance
• Hubble Space Telescope Near-IR Transmission Spectroscopy of the Super-Earth HD 97658b
• Detection of Fe I in the atmosphere of the ultra-hot Jupiter WASP-121b, and a new likelihood-based approach for Doppler-resolved spectroscopy
• A consistent retrieval analysis of 10 Hot Jupiters observed in transmission
• The Complete transmission spectrum of WASP-39b with a precise water constraint
• High-Resolution Spectroscopic Detection of TiO and Stratosphere in the Day-side of WASP-33b
• H2O abundances in the atmospheres of three hot Jupiters
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• GENESIS: New Self-Consistent Models of Exoplanetary Spectra
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) - II. A broadened sodium feature on the ultra-hot giant WASP-76b
• On degeneracies in retrievals of exoplanetary transmission spectra
• Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b
• Exoplanet atmospheres with GIANO II. Detection of molecular absorption in the dayside spectrum of HD 102195b
• New Avenues for Thermal Inversions in hot Jupiters
• Water vapor in the spectrum of the extrasolar planet HD 189733b: 2. The eclipse
• An emission spectrum for WASP-121b measured across the 0.8-1.1 micron wavelength range using the Hubble Space Telescope
• HyDRA-H: Simultaneous Hybrid Retrieval of Exoplanetary Emission Spectra
• A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
• Evidence for the Direct Detection of the Thermal Spectrum of the Non-Transiting Hot Gas Giant HD 88133 b
• Detection of Water Vapor in the Thermal Spectrum of the Non-Transiting Hot Jupiter upsilon Andromedae b
• Optimizing Ground-based Observations of O2 in Earth Analogs
• High Resolution Spectroscopy and High Contrast Imaging with the ELT : looking for O${}_2$ in Proxima b