Temporal evolution of the high-energy irradiation and water content of TRAPPIST-1 exoplanets

Abstract

The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbour liquid water on their surfaces. UV observations are essential to measure their high-energy irradiation, and to search for photodissociated water escaping from their putative atmospheres. Our new observations of TRAPPIST-1 Ly-$\alpha$ line during the transit of TRAPPIST-1c show an evolution of the star emission over three months, preventing us from assessing the presence of an extended hydrogen exosphere. Based on the current knowledge of the stellar irradiation, we investigated the likely history of water loss in the system. Planets b to d might still be in a runaway phase, and planets within the orbit of TRAPPIST-1g could have lost more than 20 Earth oceans after 8 Gyr of hydrodynamic escape. However, TRAPPIST-1e to h might have lost less than 3 Earth oceans if hydrodynamic escape stopped once they entered the habitable zone. We caution that these estimates remain limited by the large uncertainty on the planet masses. They likely represent upper limits on the actual water loss because our assumptions maximize the XUV-driven escape, while photodissociation in the upper atmospheres should be the limiting process. Late-stage outgassing could also have contributed significant amounts of water for the outer, more massive planets after they entered the habitable zone. While our results suggest that the outer planets are the best candidates to search for water with the JWST, they also highlight the need for theoretical studies and complementary observations in all wavelength domains to determine the nature of the TRAPPIST-1 planets, and their potential habitability.

arXiv comment19 pages, 14 figures, accepted for publication in AJ

References in corpus (60)

• Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
• New evolutionary models for pre-main sequence and main sequence low-mass stars down to the hydrogen-burning limit
• Theoretical Transmission Spectra During Extrasolar Giant Planet Transits
• Temperate Earth-sized planets transiting a nearby ultracool dwarf star
• Extreme Water Loss and Abiotic O${}_2$ Buildup On Planets Throughout the Habitable Zones of M Dwarfs
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Photodissociation and photoionisation of atoms and molecules of astrophysical interest
• Roche lobe effects on the atmospheric loss of "Hot Jupiters"
• The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association
• The MUSCLES Treasury Survey I: Motivation and Overview
• Stabilizing Cloud Feedback Dramatically Expands the Habitable Zone of Tidally Locked Planets
• Evolution of low-mass star and brown dwarf eclipsing binaries
• A seven-planet resonant chain in TRAPPIST-1
• Evaporation of the planet HD189733b observed in HI Lyman-alpha
• A New Family of Planets ? "Ocean Planets"
• Fundamental Parameters and Spectral Energy Distributions of Young and Field Age Objects with Masses Spanning the Stellar to Planetary Regime
• Transits of Earth-Like Planets
• A revised estimate of the occurrence rate of terrestrial planets in the habitable zones around kepler m-dwarfs
• A diagram for the evaporation status of extrasolar planets
• The habitability of Proxima Centauri b II. Possible climates and Observability
• The Ultraviolet Radiation Environment Around M dwarf Exoplanet Host Stars
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• CLES, Code Liegeois d'Evolution Stellaire
• Lyman-$\alpha$ Transit Spectroscopy and the Neutral Hydrogen Tail of the Hot Neptune GJ436b
• Temporal variations in the evaporating atmosphere of the exoplanet HD 189733b
• Water loss from Earth-sized planets in the habitable zones of ultracool dwarfs: Implications for the planets of TRAPPIST-1
• The habitability of Proxima Centauri b. I. Irradiation, rotation and volatile inventory from formation to the present
• Activity in Very Cool Stars: Magnetic Dissipation in late-M and L Dwarf Atmospheres
• Abiotic oxygen-dominated atmospheres on terrestrial habitable zone planets
• Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets
• A combined transmission spectrum of the Earth-sized exoplanets TRAPPIST-1 b and c
• The Intrinsic Extreme Ultraviolet Fluxes of F5 V to M5 V Stars
• 3D model of hydrogen atmospheric escape from HD209458b and HD189733b: radiative blow-out and stellar wind interactions
• The Different Evolution of Gas and Dust in Disks around Sun-like and Cool Stars
• Individual Dynamical Masses of Ultracool Dwarfs
• Energetic neutral atoms as the explanation for the high velocity hydrogen around HD 209458b
• Frequent flaring in the TRAPPIST-1 system - unsuited for life?
• Formation of TRAPPIST-1 and other compact systems
• An evaporating planet in the wind: stellar wind interactions with the radiatively braked exosphere of GJ436 b
• Hint of a transiting extended atmosphere on 55 Cancri b
• Atmospheric escape from HD 189733b observed in HI Lyman-alpha: detailed analysis of HST/STIS September 2011 observations
• Observations and modeling of the early acceleration phase of erupting filaments involved in coronal mass ejections
• Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1
• The Surface UV Environment on Planets Orbiting M-Dwarfs: Implications for Prebiotic Chemistry & Need for Experimental Follow-Up
• UV driven evaporation of close-in planets: energy-limited; recombination-limited and photon-limited flows
• Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman-$\alpha$ line
• Convergent Migration Renders TRAPPIST-1 Long-lived
• Short dissipation times of proto-planetary discs - an artifact of selection effects?
• Suppression of the water ice and snow albedo feedback on planets orbiting red dwarf stars and the subsequent widening of the habitable zone
• Could we identify hot Ocean-Planets with CoRoT, Kepler and Doppler velocimetry?
• Habitable Planets Around White and Brown Dwarfs: The Perils of a Cooling Primary
• UV Surface Habitability of the TRAPPIST-1 System
• Spitzer/MIPS 24 micron Observations of HD 209458b: 3 eclipses, 2.5 transits, and a Phase Curve Corrupted by Instrumental Sensitivity Variations
• The effect of Lyman $\alpha$ radiation on mini-Neptune atmospheres around M stars: application to GJ 436b
• Living with a Red Dwarf: Rotation and X-ray and Ultraviolet Properties of the Halo Population Kapteyn's Star
• Radiative braking in the extended exosphere of GJ436b
• The persistence of oceans on Earth-like planets: insights from the deep-water cycle
• No hydrogen exosphere detected around the super-Earth HD97658 b
• An observational signature of evolved oceans on extra-solar terrestrial planets
• Plausible Compositions of the Seven TRAPPIST-1 Planets Using Long-term Dynamical Simulations

Cited by in corpus (63)

• The nature of the TRAPPIST-1 exoplanets
• Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
• Atmospheric reconnaissance of the habitable-zone Earth-sized planets orbiting TRAPPIST-1
• Atmospheric Reconnaissance of TRAPPIST-1 b with JWST/NIRISS: Evidence for Strong Stellar Contamination in the Transmission Spectra
• A water budget dichotomy of rocky protoplanets from ${}^{26}$Al-heating
• Impact of Clouds and Hazes on the Simulated JWST Transmission Spectra of Habitable Zone Planets in the TRAPPIST-1 System
• The Near-Infrared Transmission Spectra of TRAPPIST-1 Planets b, c, d, e, f, and g and Stellar Contamination in Multi-Epoch Transit Spectra
• Warm terrestrial planet with half the mass of Venus transiting a nearby star
• Habitability of Exoplanet Waterworlds
• Revised mass-radius relationships for water-rich rocky planets more irradiated than the runaway greenhouse limit
• Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets Around Low-Mass Stars: the TRAPPIST-1 System
• A review of possible planetary atmospheres in the TRAPPIST-1 system
• A more comprehensive habitable zone for finding life on other planets
• Pebble-driven planet formation for TRAPPIST-1 and other compact systems
• TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Motivations and protocol version 1.0
• The TRAPPIST-1 Habitable Atmosphere Intercomparison (THAI). Part II: Moist Cases -- The Two Waterworlds
• Interior Structures and Tidal Heating in the TRAPPIST-1 Planets
• TRAPPIST-1: Global Results of the Spitzer Exploration Science Program {\it Red Worlds}
• The Mega-MUSCLES Spectral Energy Distribution Of TRAPPIST-1
• Two temperate super-Earths transiting a nearby late-type M dwarf
• Limits on Clouds and Hazes for the TRAPPIST-1 Planets
• Combined analysis of the 12.8 and 15 $\mu m$ JWST/MIRI eclipse observations of TRAPPIST-1 b
• Is pi Men c's atmosphere hydrogen-dominated? Insights from a non-detecton of Hy Ly-alpha absorption
• HST/WFC3 transmission spectroscopy of the cold rocky planet TRAPPIST-1h
• A detailed analysis of the Gl 486 planetary system
• Tidal Heating and the Habitability of the TRAPPIST-1 Exoplanets
• Can Volcanism Build Hydrogen-Rich Early Atmospheres?
• The high-energy environment and atmospheric escape of the mini-Neptune K2-18 b
• Stellar Coronal Mass Ejections
• Eyes on K2-3: A system of three likely sub-Neptunes characterized with HARPS-N and HARPS
• The GAPS Programme at TNG. XXXII. The revealing non-detection of metastable HeI in the atmosphere of the hot Jupiter WASP-80b
• On The XUV Luminosity Evolution of TRAPPIST-1
• Stellar coronal mass ejections II. Constraints from spectroscopic observations
• Do the TRAPPIST-1 Planets Have Hydrogen-rich Atmospheres?
• Near-infrared transmission spectrum of TRAPPIST-1 h using Hubble WFC3 G141 observations
• Implications of atmospheric nondetections for Trappist-1 inner planets on atmospheric retention prospects for outer planets
• Less effective hydrodynamic escape of H${}_2$-H${}_2$O atmospheres on terrestrial planets orbiting pre-main sequence M dwarfs
• A mirage of the cosmic shoreline: Venus-like clouds as a statistical false positive for exoplanet atmospheric erosion
• High-Resolution Transmission Spectroscopy of the Terrestrial Exoplanet GJ 486b
• A Coupled Analysis of Atmospheric Mass Loss and Tidal Evolution in XUV Irradiated Exoplanets: the TRAPPIST-1 Case Study
• Lyman-alpha in the GJ 1132 System: Stellar Emission and Planetary Atmospheric Evolution
• Final spin states of eccentric ocean planets
• Energy Dissipation in the Upper Atmospheres of Trappist-1 Planets
• Habitable planet formation around low-mass stars: Rapid accretion, rapid debris removal and the essential contribution of external giants
• Water delivery to the TRAPPIST-1 planets
• Surface and oceanic habitability of Trappist-1 planets under the impact of flares
• Eta-Earth Revisited II: Deriving a Maximum Number of Earth-like Habitats in the Galactic Disk
• A Deep Radio Limit for the TRAPPIST-1 System
• Observability of hydrogen-rich exospheres in Earth-like exoplanets
• The UV spectrum of the Ultracool Dwarf LSR J1835+3259 observed with the Hubble Space Telescope
• Magnetized winds of M-type stars and star-planet magnetic interactions: uncertainties and modeling strategy
• Testing Lyman alpha emission line reconstruction routines at multiple velocities in one system
• Atmospheric Overturning Circulation on Dry, Tidally-locked Rocky Planets is Mainly Driven by Radiative Cooling
• HST PanCET program: Non-detection of atmospheric escape in the warm Saturn-sized planet WASP-29 b
• High-Resolution spectral models of TRAPPIST-1e seen as a Pale Blue Dot for ELT and JWST observations
• The Fate of Oceans on First-Generation Planets Orbiting White Dwarfs
• Habitability in Brown Dwarf Systems
• Effect of vegetation on the temperatures of Trappist-1 planets
• Interaction of Trappist-1 exoplanets with coronal mass ejections: Joule heating, Poynting fluxes and the role of magnetic fields
• MHD Simulations Preliminarily Predict The Habitability and Radio Emission of TRAPPIST-1e
• Resistive MHD Simulations of Stellar Wind-Magnetosphere Coupling in TRAPPIST-1e
• L 98-59: a Benchmark System of Small Planets for Future Atmospheric Characterization
• The M-dwarf Ultraviolet Spectroscopic Sample I. Determining Stellar Parameters for Field Stars