A hydrodynamic study of the escape of metal species and excited hydrogen from the atmosphere of the hot Jupiter WASP-121b

Abstract

In the near-UV and optical transmission spectrum of the hot Jupiter WASP-121b, recent observations have detected strong absorption features of Mg, Fe, Ca, and H$\alpha$, extending outside of the planet's Roche lobe. Studying these atomic signatures can directly trace the escaping atmosphere and constrain the energy balance of the upper atmosphere. To understand these features, we introduce a detailed forward model by expanding the capability of a one-dimensional model of the upper atmosphere and hydrodynamic escape to include important processes of atomic metal species. The hydrodynamic model is coupled to a Ly$\alpha$ Monte Carlo radiative transfer calculation to simulate the excited hydrogen population and associated heating/ionization effects. Using this model, we interpret the detected atomic features in the transmission spectrum of WASP-121b and explore the impact of metals and excited hydrogen on its upper atmosphere. We demonstrate the use of multiple absorption lines to impose stronger constraints on the properties of the upper atmosphere than the analysis of a single transmission feature can provide. In addition, the model shows that line broadening due to atmospheric outflow driven by the Roche lobe overflow is necessary to explain the observed line widths and highlights the importance of the high mass-loss rate caused by the Roche lobe overflow that requires careful consideration of the structure of the lower and middle atmosphere. We also show that metal species and excited state hydrogen can play an important role in the thermal and ionization balance of ultra-hot Jupiter thermospheres.

arXiv comment35 pages, 31 figures, Accepted for publication in ApJ

References in corpus (61)

• The chemical composition of the Sun
• Atomic Data for Astrophysics. II. New Analytic Fits for Photoionization Cross Sections of Atoms and Ions
• The evaporation valley in the Kepler planets
• Atmospheric Escape from Hot Jupiters
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Roche lobe effects on the atmospheric loss of "Hot Jupiters"
• CHIANTI -- an atomic database for emission lines -- Paper XVI: Version 10, further extensions
• Helium in the eroding atmosphere of an exoplanet
• Atomic data for astrophysics. I. Radiative recombination rates for H-like, He-like, Li-like and Na-like ions over a broad range of temperature
• Stellar Lyman-alpha Emission Lines in the Hubble Space Telescope Archive: Intrinsic Line Fluxes and Absorption from the Heliosphere and Astrospheres
• The escape of heavy atoms from the ionosphere of HD209458b. I. A photochemical-dynamical model of the thermosphere
• Detection of H2O and evidence for TiO/VO in an ultra hot exoplanet atmosphere
• WASP-121 b: a hot Jupiter in a polar orbit and close to tidal disruption
• Detection of Fe I in the atmosphere of the ultra-hot Jupiter WASP-121b, and a new likelihood-based approach for Doppler-resolved spectroscopy
• An extended hydrogen envelope of the extremely hot giant exoplanet KELT-9b
• The Intrinsic Extreme Ultraviolet Fluxes of F5 V to M5 V Stars
• The HST PanCET Program: Exospheric Mg II and Fe II in the Near-UV transmission spectrum of WASP-121b using Jitter Decorrelation
• Star formation at very low metallicity. I: Chemistry and cooling at low densities
• 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
• An optical transmission spectrum for the ultra-hot Jupiter WASP-121b measured with the Hubble Space Telescope
• Atmospheric Rossiter-McLaughlin effect and transmission spectroscopy of WASP-121b with ESPRESSO
• Hot Exoplanet Atmospheres Resolved with Transit Spectroscopy (HEARTS) III. Atmospheric structure of the misaligned ultra-hot Jupiter WASP-121b
• Helium Absorption at 1083 nm from Extended Exoplanet Atmospheres: Dependence on Stellar Radiation
• Mg line formation in late-type stellar atmospheres: I. The model atom
• Ion-by-ion Cooling efficiencies
• The escape of heavy atoms from the ionosphere of HD209458b. II. Interpretation of the observations
• Detection of neutral atomic species in the ultra-hot jupiter WASP-121b
• Modelling the He I triplet absorption at 10830 Angstroms in the atmosphere of HD 209458 b
• An emission spectrum for WASP-121b measured across the 0.8-1.1 micron wavelength range using the Hubble Space Telescope
• Excitation and charge transfer in low-energy hydrogen atom collisions with neutral atoms: Theory, comparisons, and application to Ca
• Relative abundance constraints from high-resolution optical transmission spectroscopy of WASP-121b, and a fast model-filtering technique for accelerating retrievals
• Inelastic Mg+H collision data for non-LTE applications in stellar atmospheres
• The Evolving Magnetic Topology of $\tau$ Boötis
• Global 3D hydrodynamic modeling of in-transit Lyα absorption of GJ436b
• Diurnal variations in the stratosphere of the ultrahot giant exoplanet WASP-121b
• Re-visit of HST FUV observations of hot-Jupiter system HD 209458: No Si III detection and the need for COS transit observations
• An inventory of atomic species in the atmosphere of WASP-121b using UVES high-resolution spectroscopy
• Rapid escape of ultra-hot exoplanet atmospheres driven by Hydrogen Balmer absorption
• A Model of the H$\alpha$ and Na Transmission Spectrum of HD 189733b
• Neutral Cr and V in the atmosphere of ultra hot jupiter WASP-121 b
• Escaping particle fluxes in the atmospheres of close-in exoplanets. ii. reduced mass loss rates and anisotropic winds
• XUV Radiation from A-stars: Implications for Ultra-hot Jupiters
• Metastable Helium Absorptions with 3D Hydrodynamics and Self-Consistent Photochemistry I: WASP-69b, Dimensionality, XUV Flux Level, Spectral Types, and Flares
• Metastable Helium Absorptions with 3D Hydrodynamics and Self-Consistent Photochemistry II: WASP-107b, Stellar Wind, Radiation Pressure, and Shear Instability
• Swift UVOT near-UV transit observations of WASP-121 b
• A JWST NIRSpec Phase Curve for WASP-121b: Dayside Emission Strongest Eastward of the Substellar Point and Nightside Conditions Conducive to Cloud Formation
• Temporal variability of the wind from the star τ Boötis
• Evaporation of Low-Mass Planet Atmospheres: Multidimensional Hydrodynamics with Consistent Thermochemistry
• Ca line formation in late-type stellar atmospheres: I. The model atom
• Ly-alpha Radiative Transfer: Monte-Carlo Simulation of the Wouthuysen-Field Effect
• Rayleigh Scattering Cross Section Redward of Ly$\alpha$ by Atomic Hydrogen
• Modeling H$\alpha$ and He 10830 transmission spectrum of WASP-52b
• Flux conservation, radial scalings, Mach numbers, and critical distances in the solar wind: magnetohydrodynamics and Ulysses observations
• Three-dimensional modelling of absorption by various species for hot Jupiter HD 209458b
• Modelling atmospheric escape and MgII near-ultraviolet absorption of the highly irradiated hot Jupiter WASP-12b
• Emission and recombination coefficients for hydrogen with kappa-distributed electron energies
• KELT-9 as an eclipsing double-lined spectroscopic binary: a unique and self-consistent solution to the system
• Transition rates and radiative lifetimes of Ca I
• Atmosphere escape inferred from modelling the H$\alpha$ transmission spectrum of WASP-121b
• Stellar Wind Effect on the Atmospheric Escape of Hot Jupiters and their Ly-$\alpha$ and H$\alpha$ transits
• Measurement of charge-exchange between Na and \ce{Ca+} in a hybrid trap

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