Tighter constraints on the atmosphere of GJ 436 b from combined high-resolution CARMENES and CRIRES${}^{+}$ observations

Abstract

We aim to study the atmospheric properties of the warm Neptune GJ 436 b by combining a set of five transit events observed with the CARMENES spectrograph with one transit from CRIRES${}^{+}$ so as to provide the most constrained results possible at high resolution. We removed telluric and stellar signals from the data using SysRem and potential planetary signals were investigated using the cross-correlation technique. Following standard procedures for undetected species, we performed injection recovery tests and Bayesian retrievals to place constraints on the detectability of the main near-infrared absorbers. In addition, we simulated ELT/ANDES observations by computing end-to-end in silico datasets with EXoPLORE. No molecular signals were detected in the atmosphere of GJ 436 b, which is consistent with previous studies. Combined CARMENES-CRIRES${}^{+}$ injection-recovery and Bayesian retrieval analyses show that the atmosphere is likely covered by high-altitude clouds ($\sim$ $1$ mbar) at low and intermediate metallicities or, alternatively, is very metal-rich ($\gtrsim$ $900\times$ solar), which would suppress spectral features without invoking clouds. Simulations of ELT/ANDES observations suggest a boost by nearly an order of magnitude to the upper limit in the photon-limited regime, reaching $0.1$ mbar at $10$-$300\times$ solar metallicities. The joint analysis of all useful transit observations from CARMENES and CRIRES${}^{+}$ provides the most stringent constraints to date on the atmospheric properties of GJ 436 b. Complementary CCF-based and retrieval approaches consistently indicate that the atmosphere is either cloudy or highly metal enriched. Any weak near-infrared absorption lines, if present, are likely to be below current detection limits. However, according to our simulations, these features may be revealed with ELT/ANDES even in single-transit observations.

References in corpus (64)

• Gaia Data Release 3: Summary of the content and survey properties
• The James Webb Space Telescope
• Molecfit: A general tool for telluric absorption correction. I. Method and application to ESO instruments
• petitRADTRANS: a Python radiative transfer package for exoplanet characterization and retrieval
• Molecfit: A general tool for telluric absorption correction II. Quantitative evaluation on ESO-VLT X-Shooter spectra
• Spectrum radial velocity analyser (SERVAL). High-precision radial velocities and two alternative spectral indicators
• Possible thermochemical disequilibrium in the atmosphere of the exoplanet GJ 436b
• Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b
• A Sub-Neptune Exoplanet with a Low-Metallicity Methane-Depleted Atmosphere and Mie-Scattering Clouds
• An accurate, extensive, and practical line list of methane for the HITEMP database
• 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
• The CARMENES search for exoplanets around M dwarfs: Different roads to radii and masses of the target stars
• Five carbon- and nitrogen-bearing species in a hot giant planet's atmosphere
• The Complete transmission spectrum of WASP-39b with a precise water constraint
• A reflective, metal-rich atmosphere for GJ 1214b from its JWST phase curve
• CARMENES input catalogue of M dwarfs V. Luminosities, colours, and spectral energy distributions
• Habitability and Biosignatures of Hycean Worlds
• H2O abundances in the atmospheres of three hot Jupiters
• Discovery of water at high spectral resolution in the atmosphere of 51 Peg b
• A global analysis of Spitzer and new HARPS data confirms the loneliness and metal-richness of GJ 436 b
• The CARMENES search for exoplanets around M dwarfs. Stellar atmospheric parameters of target stars with SteParSyn
• Relative abundance constraints from high-resolution optical transmission spectroscopy of WASP-121b, and a fast model-filtering technique for accelerating retrievals
• CRIRES${}^{+}$ on sky at the ESO Very Large Telescope
• Analysis of Early Science observations with the CHaracterising ExOPlanets Satellite (CHEOPS) using pycheops
• Confirmation of Asymmetric Iron Absorption in WASP-76b with HARPS
• First Detection of Hydroxyl Radical Emission from an Exoplanet Atmosphere: High-dispersion Characterization of WASP-33b using Subaru/IRD
• Detection of Fe and evidence for TiO in the dayside emission spectrum of WASP-33b
• Detection of Fe\,{\sc i} Emission in the Day-side Spectrum of WASP-33b
• Formation and dynamics of water clouds on temperate sub-Neptunes: The example of K2-18b
• Stellar surface inhomogeneities as a potential source of the atmospheric signal detected in the K2-18 b transmission spectrum
• SteParSyn: A Bayesian code to infer stellar atmospheric parameters using spectral synthesis
• A Hubble PanCET Study of HAT-P-11b: A Cloudy Neptune with a Low Atmospheric Metallicity
• Seeing above the Clouds with High Resolution Spectroscopy
• An HST/STIS Optical Transmission Spectrum of Warm Neptune GJ 436b
• Revisiting Spitzer transit observations with Independent Component Analysis: new results for the GJ436 system
• High-resolution transmission spectroscopy study of ultra-hot Jupiters HAT-P-57b, KELT-17b, KELT-21b, KELT-7b, MASCARA-1b, and WASP-189b
• Robustness Measures for Molecular Detections using High-Resolution Transmission Spectroscopy of Exoplanets
• Detection of iron emission lines and a temperature inversion on the dayside of the ultra-hot Jupiter KELT-20b
• CO or no CO? Narrowing the CO abundance constraint and recovering the H2O detection in the atmosphere of WASP-127 b using SPIRou
• Atmospheric characterization of the ultra-hot Jupiter WASP-33b: Detection of Ti and V emission lines and retrieval of a broadened line profile
• A Search for FeH in Hot-Jupiter Atmospheres with High-Dispersion Spectroscopy
• The polar orbit of the warm Neptune GJ436b seen with VLT/ESPRESSO
• ARES IV: Probing the atmospheres of the two warm small planets HD 106315 c and HD 3167 c with the HST/WFC3 camera
• The First Near-Infrared Transmission Spectrum of HIP 41378 f, a Low-Mass Temperate Jovian World in a Multi-Planet System
• Aluminium oxide in the atmosphere of hot Jupiter WASP-43b
• A Near-Infrared Chemical Inventory of the Atmosphere of 55 Cancri e
• Estimating the atmospheric properties of 44 M dwarfs from SPIRou spectra
• 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
• Search for TiO and Optical Night-side Emission from the Exoplanet WASP-33b
• CRIRES${}^{+}$ transmission spectroscopy of WASP-127b. Detection of the resolved signatures of a supersonic equatorial jet and cool poles in a hot planet
• Retrieval of the dayside atmosphere of WASP-43b with CRIRES+
• High-Resolution Transmission Spectroscopy of the Terrestrial Exoplanet GJ 486b
• The space weather around the exoplanet GJ 436 b. II. Stellar wind-exoplanet interactions
• Tentative Evidence for Water Vapor in the Atmosphere of the Neptune-Size Exoplanet HD 106315 c
• ODUSSEAS: Upgraded version with new reference scale and parameter determinations for 82 planet-host M dwarf stars in SWEET-Cat
• Probing atmospheric escape through metastable He I triplet lines in 15 exoplanets observed with SPIRou
• A Mirage or an Oasis? Water Vapor in the Atmosphere of the Warm Neptune TOI-674 b
• Discriminating between hazy and clear hot-Jupiter atmospheres with CARMENES
• Flares, Rotation, Activity Cycles and a Magnetic Star-Planet Interaction Hypothesis for the Far Ultraviolet Emission of GJ 436
• Peering above the clouds of the warm Neptune GJ 436b with CRIRES+
• A formally motivated retrieval framework applied to the high resolution transmission spectrum of HD 189733 b
• The Infrared Imaging Spectrograph (IRIS) for TMT: the ADC optical design
• Retrieving day- and nightside atmospheric properties of the ultra-hot Jupiter TOI-2109b. Detection of Fe and CO emission lines and evidence for inefficient heat transport

Cited by in corpus (1)

• Using observations of escaping H/He to constrain the atmospheric composition of sub-Neptunes