Estimating the Mass Escaping Rates of Radius-valley-spanning Planets in the TOI-431 System via X-Ray and Ultraviolet Evaporation

Abstract

TOI-431 system has 3 close-in exoplanets, which gives an ideal lab to study gas escape. In this study, we measure the XUV luminosity for TOI-431 with XMM-Newton/EPIC-pn and OM data, then calculate the fluxes for the planets in the system. We find that, TOI-431 b's ${\mathrm{F}}_{\mathrm{XUV},\mathrm{b}}=$$70286_{-2611}^{+12060}$$\mathrm{erg}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$ is 75 times of TOI-431 d ${\mathrm{F}}_{\mathrm{XUV},\mathrm{d}}=$$935_{-35}^{+160}$$\mathrm{erg}\mathrm{c}{\mathrm{m}}^{-2}{\mathrm{s}}^{-1}$. Adopting the energy limit method and hydrodynamic code $ATES$ with a set of He/H ratios, we obtain the mass-loss rates of $10^{10.51_{-0.02}^{+0.07}}$ g s${}^{-1}$ for TOI-431 b, $10^{9.14_{-0.02}^{+0.07}}$ and $10^{9.84\sim 9.94}$ g s${}^{-1}$ for TOI-431 d. We predict the $2.93\sim 7.91\%$ H I Ly$\alpha$ and $0.19\sim 10.65\%$ He I triplet absorption depths for TOI-431 d, thus its gas escaping is detectable in principle. For both TOI-431 b and d, we select similar planets from the New Generation Planetary Population Synthesis (NGPPS) data. Then show that considering the mass-loss rates, TOI-431 b should be a naked solid planet, and TOI-431 d will likely maintain its gas envelope until the host star dies. According to the formation and evolution tracks, we find that TOI-431 b's potential birthplace (0.1-2 AU) should be inner than TOI-431 d (2-12 AU). Our results are consistent with the interpretation of the radius valley being caused by atmospheric escape. The intrinsic reason may be their birthplace, which will determine how close they can migrate to the host star, then lose mass and result in the Fulton gap.

arXiv comment16 pages, 14 figures, 4 tabels. Published by ApJ

References in corpus (63)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Transiting Exoplanet Survey Satellite
• On the Absorption of X-rays in the Interstellar Medium
• Collisional Plasma Models with APEC/APED: Emission Line Diagnostics of Hydrogen-like and Helium-like Ions
• Estimating distances from parallaxes. V: Geometric and photogeometric distances to 1.47 billion stars in Gaia Early Data Release 3
• The California-Kepler Survey. III. A Gap in the Radius Distribution of Small Planets
• Detection of Planetary Transits Across a Sun-like Star
• The WASP Project and the SuperWASP Cameras
• Las Cumbres Observatory Global Telescope Network
• Mass-Radius Relationships for Solid Exoplanets
• Kepler planets: a tale of evaporation
• The evaporation valley in the Kepler planets
• Atmospheric Escape from Hot Jupiters
• Detection of oxygen and carbon in the hydrodynamically escaping atmosphere of the extrasolar planet HD209458b
• A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b
• Detection of atmospheric haze on an extrasolar planet: The 0.55 - 1.05 micron transmission spectrum of HD189733b with the Hubble Space Telescope
• Roche lobe effects on the atmospheric loss of "Hot Jupiters"
• Planetary evaporation by UV & X-ray radiation: basic hydrodynamics
• Mass-Radius Relation for Rocky Planets based on PREM
• Helium in the eroding atmosphere of an exoplanet
• Evaporation of the planet HD189733b observed in HI Lyman-alpha
• Planetary population synthesis coupled with atmospheric escape: a statistical view of evaporation
• Dearth of short-period Neptunian exoplanets - a desert in period-mass and period-radius planes
• Atmospheric Escape and the Evolution of Close-in Exoplanets
• Stellar Lyman-alpha Emission Lines in the Hubble Space Telescope Archive: Intrinsic Line Fluxes and Absorption from the Heliosphere and Astrospheres
• The Next Generation Transit Survey (NGTS)
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• A New Window into Escaping Exoplanet Atmospheres: 10830 Å Line of Helium
• The New Generation Planetary Population Synthesis (NGPPS). IV. Planetary systems around low-mass stars
• Bayesian Analysis of Hot Jupiter Radius Anomalies: Evidence for Ohmic Dissipation?
• The New Generation Planetary Population Synthesis (NGPPS). I. Bern global model of planet formation and evolution, model tests, and emerging planetary systems
• AQUA: A Collection of H${}_2$O Equations of State for Planetary Models
• Viscous diffusion and photoevaporation of stellar disks
• Planet formation models: the interplay with the planetesimal disc
• The New Generation Planetary Population Synthesis (NGPPS). II. Planetary population of solar-like stars and overview of statistical results
• New observations of the extended hydrogen exosphere of the extrasolar planet HD209458b
• XUV-driven mass loss from extrasolar giant planets orbiting active stars
• Magnetically Controlled Outflows from Hot Jupiters
• Minerva-Australis I: Design, Commissioning, & First Photometric Results
• Hubble Space Telescope detection of oxygen in the atmosphere of exoplanet HD189733b
• Modelling the He I triplet absorption at 10830 Angstroms in the atmosphere of HD 209458 b
• A review of possible planetary atmospheres in the TRAPPIST-1 system
• A He I upper atmosphere around the warm Neptune GJ 3470b
• Stellar wind effects on the atmospheres of close-in giants: a possible reduction in escape instead of increased erosion
• The mass-period distribution of close-in exoplanets
• X-ray irradiation and evaporation of the four young planets around V1298 Tau
• The XUV environments of exoplanets from Jupiter-size to super-Earth
• Irradiation-driven escape of primordial planetary atmospheres I. The ATES photoionization hydrodynamics code
• Is pi Men c's atmosphere hydrogen-dominated? Insights from a non-detecton of Hy Ly-alpha absorption
• TOI-257b (HD 19916b): A Warm sub-Saturn Orbiting an Evolved F-type Star
• Modelling the He I triplet absorption at 10830 Angstroms in the atmospheres of HD 189733 b and GJ 3470 b
• 3D Aeronomy Modeling of Close-in Exoplanets
• TOI-431/HIP 26013: a super-Earth and a sub-Neptune transiting a bright, early K dwarf, with a third RV planet
• Exoplanet X-ray irradiation and evaporation rates with eROSITA
• The K2-3 system revisited: testing photoevaporation and core-powered mass loss with three small planets spanning the radius valley
• Planetary Population Synthesis and the Emergence of Four Classes of Planetary System Architectures
• Three-dimensional hydrodynamic simulations of the upper atmosphere of $\pi$ Men c: comparison with Ly$\alpha$ transit observations
• The existence and nature of the interstellar bow shock
• Implications of Recent Stellar Wind Measurements
• A Dearth of Close-In Stellar Companions to M-dwarf TESS Objects of Interest
• The XUV irradiation and likely atmospheric escape of the super-Earth $\pi$ Men c
• The shared evaporation history of three sub-Neptunes spanning the radius-period valley of a Hyades star
• Role of the impact parameter in exoplanet transmission spectroscopy

Cited by in corpus (2)

• Low 4.5 μm Dayside Emission Disfavors a Dark Bare-Rock scenario for the Hot Super-Earth TOI-431 b
• Oxygen left behind: Atmospheric Enrichment due to Fractionation in Sub-Neptunes using BOREAS