Impact of Stellar Superflares on Planetary Habitability

Abstract

High-energy radiation caused by exoplanetary space weather events from planet-hosting stars can play a crucial role in conditions promoting or destroying habitability in addition to the conventional factors. In this paper, we present the first quantitative impact evaluation system of stellar flares on the habitability factors with an emphasis on the impact of Stellar Proton Events. We derive the maximum flare energy from stellar starspot sizes and examine the impacts of flare associated ionizing radiation on CO${}_2$, H${}_2$, N${}_2$+O${}_2$ --rich atmospheres of a number of well-characterized terrestrial type exoplanets. Our simulations based on the Particle and Heavy Ion Transport code System [PHITS] suggest that the estimated ground level dose for each planet in the case of terrestrial-level atmospheric pressure (1 bar) for each exoplanet does not exceed the critical dose for complex (multi-cellular) life to persist, even for the planetary surface of Proxima Centauri b, Ross-128 b and TRAPPIST-1 e. However, when we take into account the effects of the possible maximum flares from those host stars, the estimated dose reaches fatal levels at the terrestrial lowest atmospheric depth on TRAPPIST-1 e and Ross-128 b. Large fluxes of coronal XUV radiation from active stars induces high atmospheric escape rates from close-in exoplanets suggesting that the atmospheric depth can be substantially smaller than that on the Earth. In a scenario with the atmospheric thickness of 1/10 of Earth's, the radiation dose from close-in planets including Proxima Centauri b and TRAPPIST-1 e reach near fatal dose levels with annual frequency of flare occurrence from their hoststars.

arXiv comment37 pages, 19 figures, 4 tables. Accepted for publication in The Astrophysical Journal (on June 16, 2019), Version 2 (fixed typo)

References in corpus (29)

• Habitable Zones Around Main-Sequence Stars: New Estimates
• Superflares on Solar Type Stars Observed with Kepler I. Statistical Properties of Superflares
• The Effect of a Strong Stellar Flare on the Atmospheric Chemistry of an Earth-like Planet Orbiting an M dwarf
• Understanding space weather to shield society: A global road map for 2015-2025 commissioned by COSPAR and ILWS
• The MUSCLES Treasury Survey I: Motivation and Overview
• The Kepler Catalog of Stellar Flares
• The MUSCLES Treasury Survey II: Intrinsic Lyman Alpha and Extreme Ultraviolet Spectra of K and M Dwarfs with Exoplanets
• Can Superflares Occur on Our Sun?
• The AD775 cosmic event revisited: the Sun is to blame
• The MUSCLES Treasury Survey III: X-ray to Infrared Spectra of 11 M and K Stars Hosting Planets
• Modeling Repeated M-dwarf Flaring at an Earth-like Planet in the Habitable Zone: I. Atmospheric Effects for an Unmagnetized Planet
• Ranges of Atmospheric Mass and Composition of Super Earth Exoplanets
• Statistical properties of superflares on solar-type stars based on 1-min cadence data
• Superflares on Solar-Type Stars Observed with Kepler II. Photometric Variability of Superflare-Generating Stars : A Signature of Stellar Rotation and Starspots
• Do Kepler superflare stars really include slowly-rotating Sun-like stars ? - Results using APO 3.5m telescope spectroscopic observations and Gaia-DR2 data -
• Global Energetics of Solar Flares: V. Energy Closure in Flares and Coronal Mass Ejections
• Magnetospheric Structure and Atmospheric Joule Heating of Habitable Planets Orbiting M-dwarf Stars
• Optical, UV, and X-Ray Evidence for a 7-Year Stellar Cycle in Proxima Centauri
• Risks for life on habitable planets from superflares of their host stars
• Starspot activity and superflares on solar-type stars
• Estimation of Reconnection Flux using Post-eruption Arcades and Its Relevance to 1-au Magnetic Clouds
• The full spectral radiative properties of Proxima Centauri
• Probability of CME Impact on Exoplanets Orbiting M Dwarfs and Solar-Like Stars
• High Dispersion Spectroscopy of Solar-type Superflare Stars. II. Stellar Rotation, Starspots, and Chromospheric Activities
• Scaling Relations in Coronal Mass Ejections and Energetic Proton Events associated with Solar Superflares
• Modeling Stellar Proton Event-induced particle radiation dose on close-in exoplanets
• Galactic cosmic rays on extrasolar Earth-like planets I. Cosmic ray flux
• Atmospheric Beacons of Life from Exoplanets Around G and K Stars
• High Dispersion Spectroscopy of Solar-type Superflare Stars. I. Temperature, Surface Gravity, Metallicity, and $v\sin i$

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• Persistence of Flare-Driven Atmospheric Chemistry on Rocky Habitable Zone Worlds
• Statistical Properties of Superflares on Solar-type Stars: Results Using All of the Kepler Primary Mission Data
• Time-resolved spectroscopy and photometry of an M dwarf flare star YZ Canis Minoris with OISTER and TESS: Blue asymmetry in H$\alpha$ line during the non-white light flare
• From Starspots to Stellar Coronal Mass Ejections -- Revisiting Empirical Stellar Relations
• APO & SMARTS flare star campaign observations I. Blue wing asymmetries in chromospheric lines during mid M dwarf flares from simultaneous spectroscopic and photometric observation data
• A New Model Suite to Determine the Influence of Cosmic Rays on (Exo)planetary Atmospheric Biosignatures -- Validation based on Modern Earth
• Temporal Evolution of Spatially-Resolved Individual Star Spots on a Planet-Hosting Solar-type Star: Kepler 17
• Sun-as-a-star Analysis of H$\alpha$ Spectra of a Solar Flare Observed by SMART/SDDI: Time Evolution of Red Asymmetry and Line Broadening
• Frequency of Coronal Mass Ejection Impacts with Early Terrestrial Planets and Exoplanets Around Active Solar-like Stars
• Evryscope and K2 Constraints on TRAPPIST-1 Superflare Occurrence and Planetary Habitability
• One Year in the Life of Young Suns: Data Constrained Corona-Wind Model of kappa1 Ceti
• Impact of stellar flares on the chemical composition and transmission spectra of gaseous exoplanets orbiting M dwarfs
• Propulsion of Spacecrafts to Relativistic Speeds Using Natural Astrophysical Sources
• A Superflare on YZ Canis Minoris Observed by Seimei Telescope and TESS: Red Asymmetry of H$\alpha$ Emission Associated with White-Light Emission
• 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
• New Time-Resolved, Multi-Band Flares In The GJ 65 System With gPhoton
• Transition of latitudinal differential rotation as a possible cause of weakened magnetic braking of solar-type stars
• A Study of the Magnetic Activity and Variability of GJ 436
• Tidally driven tectonic activity as a parameter in exoplanet habitability
• Characteristics of aquatic biospheres on temperate planets around Sun-like stars and M-dwarfs
• J-PLUS: Discovery and characterisation of ultracool dwarfs using Virtual Observatory tools II. Second data release and machine learning methodology
• A Seven-Day Multi-Wavelength Flare Campaign on AU Mic III: Quiescent and Flaring Properties of the X-ray Spectra and Chromospheric lines
• Space Weather Observations, Modeling, and Alerts in Support of Human Exploration of Mars
• Cost estimation for alternative aviation plans against potential radiation exposure associated with solar proton events for the airline industry
• Connecting Solar and Stellar Flares/CMEs: Expanding Heliophysics to Encompass Exoplanetary Space Weather
• Delivery of icy planetesimals to inner planets in the Proxima Centauri planetary system
• The Flare-Activity of 2MASSJ16111534-1757214 in the Upper Scorpius association
• Temporal Variation of Flare Occurrence Rates via the Spot Evolution on the Sun and Solar-type Stars