A Search for FeH in Hot-Jupiter Atmospheres with High-Dispersion Spectroscopy

Abstract

Most of the molecules detected thus far in exoplanet atmospheres, such as water and CO, are present for a large range of pressures and temperatures. In contrast, metal hydrides exist in much more specific regimes of parameter space, and so can be used as probes of atmospheric conditions. Iron hydride (FeH) is a dominant source of opacity in low-mass stars and brown dwarfs, and evidence for its existence in exoplanets has recently been observed at low resolution. We performed a systematic search of archival CARMENES near-infrared data for signatures of FeH during transits of 12 exoplanets. These planets span a large range of equilibrium temperatures (600 $\lesssim T_{eq}\lesssim$ 4000K) and surface gravities (2.5 $\lesssim \log g\lesssim$ 3.5). We did not find a statistically significant FeH signal in any of the atmospheres, but obtained potential low-confidence signals (SNR$\sim$3) in two planets, WASP-33b and MASCARA-2b. Previous modeling of exoplanet atmospheres indicate that the highest volume mixing ratios (VMRs) of 10${}^{-7}$ to 10${}^{-9}$ are expected for temperatures between 1800 and 3000K and log $g\gtrsim 3$. The two planets for which we find low-confidence signals are in the regime where strong FeH absorption is expected. We performed injection and recovery tests for each planet and determined that FeH would be detected in every planet for VMRs $\ge 10^{-6}$, and could be detected in some planets for VMRs as low as 10${}^{-9.5}$. Additional observations are necessary to conclusively detect FeH and assess its role in the temperature structures of hot Jupiter atmospheres.

arXiv commentAccepted to AAS journals

References in corpus (98)

• The NumPy array: a structure for efficient numerical computation
• Gaia Data Release 2. Summary of the contents and survey properties
• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• Analytic Lightcurves for Planetary Transit Searches
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Detection of an Extrasolar Planet Atmosphere
• The effects of snowlines on C/O in planetary atmospheres
• A continuum from clear to cloudy hot-Jupiter exoplanets without primordial water depletion
• Models of Stars, Brown Dwarfs and Exoplanets
• The orbital motion, absolute mass, and high-altitude winds of exoplanet HD209458b
• A Unified Theory for the Atmospheres of the Hot and Very Hot Jupiters: Two Classes of Irradiated Atmospheres
• 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
• Correcting systematic effects in a large set of photometric lightcurves
• Infrared Transmission Spectroscopy of the Exoplanets HD209458b and XO-1b Using the Wide Field Camera-3 on the Hubble Space Telescope
• A Neptune-Mass Planet Orbiting the Nearby M Dwarf GJ 436
• A Possible Bifurcation in Atmospheres of Strongly Irradiated Stars and Planets
• Accurate, Empirical Radii and Masses of Planets and their Host Stars with Gaia Parallaxes
• The prevalence of dust on the exoplanet HD 189733b from Hubble and Spitzer observations
• The signature of orbital motion from the dayside of the planet tau Bootis b
• HAT-P-11b: A Super-Neptune Planet Transiting a Bright K Star in the Kepler Field
• Rayleigh scattering in the transit spectrum of HD 189733b
• The imprint of exoplanet formation history on observable present-day spectra of hot Jupiters
• Detection of water absorption in the day side atmosphere of HD 189733 b using ground-based high-resolution spectroscopy at 3.2 microns
• Gaseous Mean Opacities for Giant Planet and Ultracool Dwarf Atmospheres over a Range of Metallicities and Temperatures
• Helium in the eroding atmosphere of an exoplanet
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• The GAPS Programme with HARPS-N@TNG XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets
• The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer
• Spectrally resolved detection of sodium in the atmosphere of HD189733b with the HARPS spectrograph
• Can TiO Explain Thermal Inversions in the Upper Atmospheres of Irradiated Giant Planets?
• Nightside condensation of iron in an ultra-hot giant exoplanet
• H- Opacity and Water Dissociation in the Dayside Atmosphere of the Very Hot Gas Giant WASP-18 b
• Atmospheric Escape and the Evolution of Close-in Exoplanets
• Ground-based detection of an extended helium atmosphere in the Saturn-mass exoplanet WASP-69b
• Ground-based detection of sodium in the transmission spectrum of exoplanet HD209458b
• A giant planet undergoing extreme ultraviolet irradiation by its hot massive-star host
• Evidence for Cloud Disruption in the L/T Dwarf Transition
• Atmospheric Chemistry in Giant Planets, Brown Dwarfs, and Low-Mass Dwarf Stars III. Iron, Magnesium, and Silicon
• Extremely Irradiated Hot Jupiters: Non-Oxide Inversions, H- Opacity, and Thermal Dissociation of Molecules
• Starspots, spin-orbit misalignment, and active latitudes in the HAT-P-11 exoplanetary system
• Rotation and winds of exoplanet HD 189733 b measured with high-dispersion transmission spectroscopy
• Spectrally resolved helium absorption from the extended atmosphere of a warm Neptune-mass exoplanet
• PyTransit: Fast and Easy Exoplanet Transit Modelling in Python
• HST hot-Jupiter transmission spectral survey: detection of potassium in WASP-31b along with a cloud deck and Rayleigh scattering
• Detection of H2O and evidence for TiO/VO in an ultra hot exoplanet atmosphere
• Observing transiting planets with JWST -- Prime targets and their synthetic spectral observations
• An extended hydrogen envelope of the extremely hot giant exoplanet KELT-9b
• Barycentric Corrections at 1 cm/s for precise Doppler velocities
• The atmospheric circulation of a nine-hot Jupiter sample: Probing circulation and chemistry over a wide phase space
• Atmospheric characterization of the ultra-hot Jupiter MASCARA-2b/KELT-20b
• Gaia Data Release 2: The catalogue of radial velocity standard stars
• High-Resolution Spectroscopic Detection of TiO and Stratosphere in the Day-side of WASP-33b
• HAT-P-32b and HAT-P-33b: Two Highly Inflated Hot Jupiters Transiting High-Jitter Stars
• An optical transmission spectrum for the ultra-hot Jupiter WASP-121b measured with the Hubble Space Telescope
• Detection of molecular absorption in the dayside of exoplanet 51 Pegasi b?
• Orbital misalignment of the Neptune-mass exoplanet GJ 436b with the spin of its cool star
• Three sub-Jupiter-mass planets: WASP-69b & WASP-84b transit active K dwarfs and WASP-70Ab transits the evolved primary of a G4+K3 binary
• Clouds, Gravity and Metallicity in Blue L dwarfs: The Case of 2MASS J11263991-5003550
• Quantifying and Predicting the Presence of Clouds in Exoplanet Atmospheres
• 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
• High-resolution confirmation of an extended helium atmosphere around WASP-107b
• Three irradiated and bloated hot Jupiters: WASP-76b, WASP-82b & WASP-90b
• A framework to combine low- and high-resolution spectroscopy for the atmospheres of transiting exoplanets
• Ionized calcium in the atmospheres of two ultra-hot exoplanets WASP-33b and KELT-9b
• Ground-based near-UV observations of 15 transiting exoplanets: Constraints on their atmospheres and no evidence for asymmetrical transits
• The discoveries of WASP-91b, WASP-105b and WASP-107b: two warm Jupiters and a planet in the transition region between ice giants and gas giants
• Detection of sodium in the atmosphere of WASP-69b
• He I $\lambda$ 10830 Å in the transmission spectrum of HD 209458 b
• On the robustness of analysis techniques for molecular detections using high resolution exoplanet spectroscopy
• CRIRES spectroscopy and empirical line-by-line identification of FeH molecular absorption in an M dwarf
• KELT-20b: A giant planet with a period of P~ 3.5 days transiting the V~ 7.6 early A star HD 185603
• Exoplanet Clouds
• Evidence for a Dayside Thermal Inversion and High Metallicity for the Hot Jupiter WASP-18b
• Connecting planet formation and astrochemistry: A main sequence for C/O in hot-exoplanetary atmospheres
• HAT-P-11: Discovery of a Second Planet and a Clue to Understanding Exoplanet Obliquities
• Non-detection of TiO and VO in the atmosphere of WASP-121b using high-resolution spectroscopy
• Multiple water band detections in the CARMENES near-infrared transmission spectrum of HD 189733 b
• Measurement of the Nodal Precession of WASP-33 b via Doppler Tomography
• HAT-P-57b: A Short-Period Giant Planet Transiting A Bright Rapidly Rotating A8V Star Confirmed Via Doppler Tomography
• ARES II: Characterising the Hot Jupiters WASP-127 b, WASP-79 b and WASP-62 b with HST
• Water vapor detection in the transmission spectra of HD 209458 b with the CARMENES NIR channel
• The Influence of Host Star Spectral Type on Ultra-Hot Jupiter Atmospheres
• MASCARA-2 b: A hot Jupiter transiting the $m_V=7.6$ A-star HD185603
• The GAPS Programme with HARPS-N at TNG XIX. Atmospheric Rossiter-McLaughlin effect and improved parameters of KELT-9b
• Surface Gravities for 228 M, L, and T Dwarfs in the NIRSPEC Brown Dwarf Spectroscopic Survey
• The Metal-Rich Atmosphere of the Neptune HAT-P-26b
• High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood
• Precise photometric transit follow-up observations of five close-in exoplanets : update on their physical properties
• From cold to hot irradiated gaseous exoplanets: Fingerprints of chemical disequilibrium in atmospheric spectra
• Strong H$\alpha$ emission and signs of accretion in a circumbinary planetary mass companion from MUSE
• Hubble PanCET: An isothermal day-side atmosphere for the bloated gas-giant HAT-P-32Ab
• Transmission Spectroscopy of WASP-79b from 0.6 to 5.0 $\mu$m
• The GTC exoplanet transit spectroscopy survey. IV. Confirmation of the flat transmission spectrum of HAT-P-32b
• Accurate parameters for HD 209458 and its planet from HST spectrophotometry
• Search for TiO and Optical Night-side Emission from the Exoplanet WASP-33b
• Near-IR transmission spectrum of HAT-P-32 b using HST/WFC3

Cited by in corpus (25)

• An Atomic Spectral Survey of WASP-76b: Resolving Chemical Gradients and Asymmetries
• Confirmation of Asymmetric Iron Absorption in WASP-76b with HARPS
• Carbon monoxide emission lines reveal an inverted atmosphere in the ultra hot Jupiter WASP-33 b consistent with an eastward hot spot
• Detection of OH in the ultra-hot Jupiter WASP-76b
• Detection of the hydrogen Balmer lines in the ultra-hot Jupiter WASP-33b
• 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
• Black Mirror: The impact of rotational broadening on the search for reflected light from 51 Pegasi b with high resolution spectroscopy
• HST PanCET Program: A Complete Near-UV to Infrared Transmission Spectrum for the Hot Jupiter WASP-79b
• The ESO SupJup Survey I: Chemical and isotopic characterisation of the late L-dwarf DENIS J0255-4700 with CRIRES${}^{+}$
• Searching for the origin of the Ehrenreich effect in ultra-hot Jupiters: Evidence for strong C/O gradients in the atmosphere of WASP-76b?
• Silicon in the dayside atmospheres of two ultra-hot Jupiters
• The PEPSI Exoplanet Transit Survey (PETS). II. A Deep Search for Thermal Inversion Agents in KELT-20 b/MASCARA-2 b with Emission and Transmission Spectroscopy
• Unifying High- and Low-resolution Observations to Constrain the Dayside Atmosphere of KELT-20b/MASCARA-2b
• The GAPS Programme at TNG XXXIII. HARPS-N detects multiple atomic species in emission from the dayside of KELT-20b
• Transmission spectroscopy of MASCARA-1b with ESPRESSO: Challenges of overlapping orbital and Doppler tracks
• The GAPS programme at TNG. XLV. HI Balmer lines transmission spectroscopy and NLTE atmospheric modelling of the ultra-hot Jupiter KELT-20b/MASCARA-2b
• Evidence for chromium hydride in the atmosphere of Hot Jupiter WASP-31b
• Applications of a Gaussian Process Framework for Modelling of High-Resolution Exoplanet Spectra
• 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
• Extreme winds on the emerging dayside of an ultrahot Jupiter
• Tighter constraints on the atmosphere of GJ 436 b from combined high-resolution CARMENES and CRIRES${}^{+}$ observations
• NLTE atmospheric modelling of the ultra-hot Jupiter WASP-178b and comparison with UV and optical observations
• Detection of Na in the atmosphere of the hot Jupiter HAT-P-55b