Peering above the clouds of the warm Neptune GJ 436b with CRIRES+

Abstract

Exoplanets with masses between Earth and Neptune are amongst the most commonly observed, yet their properties are poorly constrained. Their transmission spectra are often featureless, which indicate either high-altitude clouds or a high atmospheric metallicity. The archetypical warm Neptune GJ 436b is such a planet showing a flat transmission spectrum in observations with the Hubble Space Telescope (HST). Ground-based high-resolution spectroscopy (HRS) effectively probes exoplanet atmospheres at higher altitudes and can therefore be more sensitive to absorption coming from above potential cloud decks. In this paper we aim to investigate this for the exoplanet GJ 436b. We present new CRIRES+ HRS transit data of GJ 436b. Three transits were observed, but since two were during bad weather conditions, only one transit was analyzed. The radiative transfer code petitRADTRANS was used to create atmospheric models for cross-correlation and signal-injection purposes, including absorption from H${}_2$O, CH${}_4$, and CO. No transmission signals were detected, but atmospheric constraints can be derived. Injection of artificial transmission signals indicate that if GJ 436b would have a cloud deck at pressures P>10 mbar and a <300$\times$ solar metallicity, these CRIRES+ observations should have resulted in a detection. We estimate that the constraints presented here from one ground-based HRS transit are slightly better than those obtained with four HST transits. Combining HRS data from multiple transits is an interesting avenue for future studies of exoplanets with high-altitude clouds.

arXiv commentAccepted for publication by A&A on July 5th, 2024

References in corpus (51)

• The chemical composition of the Sun
• The Transiting Exoplanet Survey Satellite
• Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler
• The false positive rate of Kepler and the occurrence of planets
• Planetary Candidates Observed by Kepler, III: Analysis of the First 16 Months of Data
• Characteristics of planetary candidates observed by Kepler, II: Analysis of the first four months of data
• Clouds in the atmosphere of the super-Earth exoplanet GJ 1214b
• The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b
• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• Correcting systematic effects in a large set of photometric lightcurves
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Improved parameters for extrasolar transiting planets
• A Neptune-Mass Planet Orbiting the Nearby M Dwarf GJ 436
• C/O ratio as a Dimension for Characterizing Exoplanetary Atmospheres
• The signature of orbital motion from the dayside of the planet tau Bootis b
• A ground-based transmission spectrum of the super-Earth exoplanet GJ1214b
• A featureless transmission spectrum for the Neptune-mass exoplanet GJ 436b
• Nightside condensation of iron in an ultra-hot giant exoplanet
• Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b
• An atmospheric radiation model for Cerro Paranal. I. The optical spectral range
• Compositional diversity in the atmospheres of hot Neptunes, with application to GJ 436b
• Detection of transits of the nearby hot Neptune GJ 436 b
• Ground-based detection of an extended helium atmosphere in the Saturn-mass exoplanet WASP-69b
• Rotation and winds of exoplanet HD 189733 b measured with high-dispersion transmission spectroscopy
• An accurate, extensive, and practical line list of methane for the HITEMP database
• Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets
• Efficient fitting of multiplanet Keplerian models to radial velocity and astrometry data
• An advanced scattered moonlight model for Cerro Paranal
• The CARMENES search for exoplanets around M dwarfs. First visual-channel radial-velocity measurements and orbital parameter updates of seven M-dwarf planetary systems
• Forward and Inverse Modeling of the Emission and Transmission Spectrum of GJ 436b: Investigating Metal Enrichment, Tidal Heating, and Clouds
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• The nature and origins of sub-Neptune size planets
• The Nature of the Atmosphere of the Transiting Super-Earth GJ 1214b
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• Thermochemistry and Photochemistry in Cooler Hydrogen Dominated Extrasolar Planets: The Case of GJ436b
• High Metallicity and Non-equilibrium Chemistry in the Dayside Atmosphere of hot-Neptune GJ 436b
• A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b
• Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits
• Benchmarking the power of amateur observatories for TTV exoplanets detection
• SPIRou Input Catalogue: Global properties of 440 M dwarfs observed with ESPaDOnS at CFHT
• Near-infrared transmission spectrum of the warm-uranus GJ 3470b with the Wide Field Camera-3 on the Hubble Space Telescope
• The puzzling chemical composition of GJ 436b's atmosphere: influence of tidal heating on the chemistry
• High-resolution Transmission Spectroscopy of MASCARA-2 b with EXPRES
• Bulk composition of the transiting hot Neptune around GJ 436
• Seeing above the Clouds with High Resolution Spectroscopy
• An HST/STIS Optical Transmission Spectrum of Warm Neptune GJ 436b
• Prospects for Characterizing the Haziest Sub-Neptune Exoplanets with High Resolution Spectroscopy
• Interior structure models of GJ 436b
• A Search for FeH in Hot-Jupiter Atmospheres with High-Dispersion Spectroscopy
• The GAPS Programme at TNG LV. Multiple molecular species in the atmosphere of HAT-P-11 b and review of the HAT-P-11 planetary system
• Characterising Atmospheres of Cloudy Temperate Mini-Neptunes with JWST

Cited by in corpus (5)

• CRIRES${}^{+}$ transmission spectroscopy of WASP-127b. Detection of the resolved signatures of a supersonic equatorial jet and cool poles in a hot planet
• Instrumentation prospects for rocky exoplanet atmospheres studies with high resolution spectroscopy
• Tighter constraints on the atmosphere of GJ 436 b from combined high-resolution CARMENES and CRIRES${}^{+}$ observations
• Modelling helium in exoplanet atmospheres. A revised network with photoelectron-driven processes
• Sub-Neptunes as Soot Factories: Deep Atmosphere Hydrocarbon Formation and Quenching as the Origin of Sub-Neptune Aerosol Trends