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Persistence of flare-driven atmospheric chemistry on rocky habitable zone worlds

Nature Astronomy volume 5, pages 298–310 (2021)Cite this article

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Abstract

Low-mass stars show evidence of vigorous magnetic activity in the form of large flares and coronal mass ejections. Such space weather events may have important ramifications for the habitability and observational fingerprints of exoplanetary atmospheres. Here, using a suite of three-dimensional coupled chemistry–climate model simulations, we explore effects of time-dependent stellar activity on rocky planet atmospheres orbiting G, K and M dwarf stars. We employ observed data from the MUSCLES campaign and the Transiting Exoplanet Survey Satellite and test a range of rotation period, magnetic field strength and flare frequency assumptions. We find that recurring flares drive the atmospheres of planets around K and M dwarfs into chemical equilibria that substantially deviate from their pre-flare regimes, whereas the atmospheres of G dwarf planets quickly return to their baseline states. Interestingly, simulated O2-poor and O2-rich atmospheres experiencing flares produce similar mesospheric nitric oxide abundances, suggesting that stellar flares can highlight otherwise undetectable chemical species. Applying a radiative transfer model to our chemistry–climate model results, we find that flare-driven transmission features of bio-indicating chemical species, such as nitrogen dioxide, nitrous oxide and nitric acid, show particular promise for detection by future instruments.

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Fig. 1: Observed flare light curves and spectra used as inputs for CCM simulations.
Fig. 2: Spatial and temporal atmospheric effects of repeated stellar flares on a G-star planet.
Fig. 3: Spatial and temporal atmospheric effects of repeated stellar flaring on a K-star planet.
Fig. 4: Global-mean vertical profiles of atmospheric species.
Fig. 5: Global-mean vertical profiles of atmospheric species for non-modern-Earth climate archetypes.
Fig. 6: Simulated transmission spectra for two endmember planetary scenarios.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon request. The raw data are publicly available at https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html (MAST) and https://archive.stsci.edu/prepds/muscles/ (MUSCLES) and the solar ion pair production rates are available at https://solarisheppa.geomar.de/solarprotonfluxes.

Code availability

The unmodified climate model used in this study is available for public download at http://www.cesm.ucar.edu/models/cesm1.2/cesm/doc/usersguide/x290.html. Components of the modified version of the climate can be obtained via ExoCam at https://github.com/storyofthewolf/ExoCAM and by request from E.T.W. (eric.wolf@colorado.edu). The stella package can be downloaded at https://github.com/afeinstein20/stella. The remaining codes that support the results within this paper and other findings of this study are available from the corresponding author on request.

References

  1. Borucki, W. J. et al. Kepler planet-detection mission: introduction and first results. Science 327, 977–980 (2010).

    ADS  Google Scholar 

  2. Kopparapu, R. K. A revised estimate of the occurrence rate of terrestrial planets in the habitable zones around Kepler M-dwarfs. Astrophys. J. Lett. 767, L8 (2013).

    ADS  Google Scholar 

  3. Mulders, G. D., Pascucci, I., Apai, D. & Ciesla, F. J. The exoplanet population observation simulator. I. The inner edges of planetary systems. Astron. J. 156, 24 (2018).

    ADS  Google Scholar 

  4. Hsu, D. C., Ford, E. B., Ragozzine, D. & Ashby, K. Occurrence rates of planets orbiting FGK stars: combining Kepler DR25, Gaia DR2, and Bayesian inference. Astron. J. 158, 109 (2019).

    ADS  Google Scholar 

  5. Bryson, S. et al. The occurrence of rocky habitable zone planets around solar-like stars from Kepler data. Preprint at https://arxiv.org/abs/2010.14812 (2020).

  6. Kasting, J. F., Whitmire, D. P. & Reynolds, R. T. Habitable zones around main sequence stars. Icarus 101, 108–128 (1993).

    ADS  Google Scholar 

  7. Kasting, J. F., Chen, H. & Kopparapu, R. K. Stratospheric temperatures and water loss from moist greenhouse atmospheres of Earth-like planets. Astrophys. J. 813, L3 (2015).

    ADS  Google Scholar 

  8. Ricker, G. R. et al. Transiting exoplanet survey satellite. J. Astron. Telesc. Instrum. Syst. 1, 014003 (2014).

    ADS  Google Scholar 

  9. Ballard, S. Predicted number, multiplicity, and orbital dynamics of TESS M-dwarf exoplanets. Astron. J. 157, 113 (2019).

    ADS  Google Scholar 

  10. Dalba, P. A. et al. Predicted yield of transits of known radial velocity exoplanets from the TESS primary and extended missions. Publ. Astron. Soc. Pac. 131, 034401 (2019).

    ADS  Google Scholar 

  11. Scalo, J. et al. M stars as targets for terrestrial exoplanet searches and biosignature detection. Astrobiology 7, 85–166 (2007).

    ADS  Google Scholar 

  12. Linsky, J. L. Stellar model chromospheres and spectroscopic diagnostics. Annu. Rev. Astron. Astrophys. 55, 159–211 (2017).

    ADS  Google Scholar 

  13. Airapetian, V. S. et al. Impact of space weather on climate and habitability of terrestrial type exoplanets. Int. J. Astrobiol. 19, 136–194 (2020).

    ADS  Google Scholar 

  14. Tian, F. & Ida, S. Water contents of Earth-mass planets around M dwarfs. Nat. Geosci. 8, 177–180 (2015).

    ADS  Google Scholar 

  15. Becker, J., Gallo, E., Hodges-Kluck, E., Adams, F. C. & Barnes, R. A coupled analysis of atmospheric mass loss and tidal evolution in XUV irradiated exoplanets: the TRAPPIST-1 case study. Astron. J. 159, 275 (2020).

    ADS  Google Scholar 

  16. Thurairajah, B., Bailey, S. M. & Hervig, M. E. Northern hemisphere summer mesospheric gravity wave response to solar activity from nine years of aim observation. J. Atmos. Sol. Terr. Phys. 193, 105086 (2019).

    Google Scholar 

  17. Atri, D. Modelling stellar proton event-induced particle radiation dose on close-in exoplanets. Mon. Not. R. Astron. Soc. 465, L34–L38 (2017).

    ADS  Google Scholar 

  18. Yamashiki, Y. A. et al. Impact of stellar superflares on planetary habitability. Astrophys. J. 881, 114 (2019).

    ADS  Google Scholar 

  19. Airapetian, V. S., Jackman, C. H., Mlynczak, M., Danchi, W. & Hunt, L. Atmospheric beacons of life from exoplanets around G and K stars. Sci. Rep. 7, 14141 (2017).

    ADS  Google Scholar 

  20. Hawley, S. L. & Pettersen, B. R. The great flare of 1985 April 12 on AD Leonis. Astrophys. J. 378, 725 (1991).

    ADS  Google Scholar 

  21. Segura, A., Walkowicz, L. M., Meadows, V., Kasting, J. & Hawley, S. The effect of a strong stellar flare on the atmospheric chemistry of an Earth-like planet orbiting an M dwarf. Astrobiology 10, 751–771 (2010).

    ADS  Google Scholar 

  22. Tilley, M. A., Segura, A., Meadows, V., Hawley, S. & Davenport, J. Modeling repeated M dwarf flaring at an Earth-like planet in the habitable zone: atmospheric effects for an unmagnetized planet. Astrobiology 19, 64–86 (2019).

    ADS  Google Scholar 

  23. Grenfell, J. L. et al. Response of atmospheric biomarkers to NOx-induced photochemistry generated by stellar cosmic rays for Earth-like planets in the habitable zone of M dwarf stars. Astrobiology 12, 1109–1122 (2012).

    ADS  Google Scholar 

  24. Venot, O., Rocchetto, M., Carl, S., Roshni Hashim, A. & Decin, L. Influence of stellar flares on the chemical composition of exoplanets and spectra. Astrophys. J. 830, 77 (2016).

    ADS  Google Scholar 

  25. Krissansen-Totton, J., Olson, S. & Catling, D. C. Disequilibrium biosignatures over Earth history and implications for detecting exoplanet life. Sci. Adv. 4, eaao5747 (2018).

    ADS  Google Scholar 

  26. Schwieterman, E. W. et al. Exoplanet biosignatures: a review of remotely detectable signs of life. Astrobiology 18, 663–708 (2018).

    ADS  Google Scholar 

  27. Des Marais, D. J. et al. Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets. Astrobiology 2, 153–181 (2002).

    ADS  Google Scholar 

  28. Tabataba-Vakili, F., Grenfell, J. L., Grießmeier, J. M. & Rauer, H. Atmospheric effects of stellar cosmic rays on Earth-like exoplanets orbiting M-dwarfs. Astron. Astrophys. 585, A96 (2016).

    Google Scholar 

  29. Scheucher, M. et al. New insights into cosmic-ray-induced biosignature chemistry in Earth-like atmospheres. Astrophys. J. 863, 6 (2018).

    ADS  Google Scholar 

  30. Yang, J., Cowan, N. B. & Abbot, D. S. Stabilizing cloud feedback dramatically expands the habitable zone of tidally locked planets. Astrophys. J. Lett. 771, L45 (2013).

    ADS  Google Scholar 

  31. Chen, H., Wolf, E. T., Kopparapu, R., Domagal-Goldman, S. & Horton, D. E. Biosignature anisotropy modeled on temperate tidally locked M-dwarf planets. Astrophys. J. Lett. 868, L6 (2018).

    ADS  Google Scholar 

  32. Chen, H., Wolf, E. T., Zhan, Z. & Horton, D. E. Habitability and spectroscopic observability of warm M-dwarf exoplanets evaluated with a 3D chemistry-climate model. Astrophys. J. 886, 16 (2019).

    ADS  Google Scholar 

  33. Loyd, R. O. P. et al. The MUSCLES Treasury Survey. V. FUV flares on active and inactive M dwarfs. Astrophys. J. 867, 71 (2018).

    ADS  Google Scholar 

  34. Peacock, S., Barman, T., Shkolnik, E. L., Hauschildt, P. H. & Baron, E. Predicting the extreme ultraviolet radiation environment of exoplanets around low-mass stars: the TRAPPIST-1 system. Astrophys. J. 871, 235 (2019).

    ADS  Google Scholar 

  35. Marsh, D. R. et al. Climate change from 1850 to 2005 simulated in CESM1(WACCM). J. Clim. 26, 7372–7391 (2013).

    ADS  Google Scholar 

  36. Way, M. J. et al. Was Venus the first habitable world of our solar system? Geophys. Res. Lett. 43, 8376–8383 (2016).

    ADS  Google Scholar 

  37. Shields, A. L., Bitz, C. M., Meadows, V. S., Joshi, M. M. & Robinson, T. D. Spectrum-driven planetary deglaciation due to increases in stellar luminosity. Astrophys. J. Lett. 785, L9 (2014).

    ADS  Google Scholar 

  38. Checlair, J., Menou, K. & Abbot, D. S. No snowball on habitable tidally locked planets. Astrophys. J. 845, 132 (2017).

    ADS  Google Scholar 

  39. Checlair, J. H., Olson, S. L., Jansen, M. F. & Abbot, D. S. No snowball on habitable tidally locked planets with a dynamic ocean. Astrophys. J. Lett. 884, L46 (2019).

    ADS  Google Scholar 

  40. Olson, S. L., Jansen, M. & Abbot, D. S. Oceanographic considerations for exoplanet life detection. Astrophys. J. 895, 19 (2020).

    ADS  Google Scholar 

  41. Christensen, U. R., Holzwarth, V. & Reiners, A. Energy flux determines magnetic field strength of planets and stars. Nature 457, 167–169 (2009).

    ADS  Google Scholar 

  42. Lean, J., Beer, J. & Bradley, R. Reconstruction of solar irradiance since 1610: implications for climate change. Geophys. Res. Lett. 22, 3195–3198 (1995).

    ADS  Google Scholar 

  43. France, K. et al. The MUSCLES Treasury Survey. I. Motivation and overview. Astrophys. J. 820, 89 (2016).

    ADS  Google Scholar 

  44. Feinstein, A. D. et al. Flare statistics for young stars from a convolutional neural network analysis of TESS data. Astron. J. 160, 219 (2020).

    ADS  Google Scholar 

  45. Youngblood, A. et al. The MUSCLES Treasury Survey. IV. Scaling relations for ultraviolet, Ca II K, and energetic particle fluxes from M dwarfs. Astrophys. J. 843, 31 (2017).

    ADS  Google Scholar 

  46. Jackman, C. H. et al. Neutral atmospheric influences of the solar proton events in October–November 2003. J. Geophys. Res. Space Phys. 110, A09S27 (2005).

  47. Solomon, S., Rusch, D. W., Gerard, J. C., Reid, G. C. & Crutzen, P. J. The effect of particle precipitation events on the neutral and ion chemistry of the middle atmosphere: II. Odd hydrogen. Planet. Space Sci. 29, 885–893 (1981).

    ADS  Google Scholar 

  48. Segura, A. in Handbook of Exoplanets (eds Deeg, H. & Belmonte, J.) 2995–3017 (Springer, 2018).

  49. Günther, M. N. et al. Stellar flares from the first TESS data release: exploring a new sample of M dwarfs. Astron. J. 159, 60 (2020).

    ADS  Google Scholar 

  50. Carone, L., Keppens, R., Decin, L. & Henning, T. Stratosphere circulation on tidally locked ExoEarths. Mon. Not. R. Astron. Soc. 473, 4672–4685 (2018).

    ADS  Google Scholar 

  51. Funke, B. et al. Downward transport of upper atmospheric NOx into the polar stratosphere and lower mesosphere during the Antarctic 2003 and Arctic 2002/2003 winters. J. Geophys. Res. Atmos. 110, D24308 (2005).

    ADS  Google Scholar 

  52. Kasting, J. F. Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus. Icarus 74, 472–494 (1988).

    ADS  Google Scholar 

  53. Fauchez, T. J. et al. Impact of clouds and hazes on the simulated JWST transmission spectra of habitable zone planets in the TRAPPIST-1 system. Astrophys. J. 887, 194 (2019).

    ADS  Google Scholar 

  54. Komacek, T. D., Fauchez, T. J., Wolf, E. T. & Abbot, D. S. Clouds will likely prevent the detection of water vapor in JWST transmission spectra of terrestrial exoplanets. Astrophys. J. Lett. 888, L20 (2020).

    ADS  Google Scholar 

  55. Suissa, G. et al. Dim prospects for transmission spectra of ocean Earths around M stars. Astrophys. J. 891, 58 (2020).

    ADS  Google Scholar 

  56. Dong, C. et al. The dehydration of water worlds via atmospheric losses. Astrophys. J. Lett. 847, L4 (2017).

    ADS  Google Scholar 

  57. Mordasini, C. Planetary evolution with atmospheric photoevaporation. I. Analytical derivation and numerical study of the evaporation valley and transition from super-Earths to sub-Neptunes. Astron. Astrophys. 638, A52 (2020).

    ADS  Google Scholar 

  58. Davenport, J. R. A. The Kepler catalog of stellar flares. Astrophys. J. 829, 23 (2016).

    ADS  Google Scholar 

  59. Yang, H. et al. The flaring activity of M dwarfs in the Kepler field. Astrophys. J. 849, 36 (2017).

    ADS  Google Scholar 

  60. Kite, E. S. & Barnett, M. N. Exoplanet secondary atmosphere loss and revival. Proc. Natl Acad. Sci. USA 117, 18264–18271 (2020).

    ADS  Google Scholar 

  61. Domagal-Goldman, S. D., Meadows, V. S., Claire, M. W. & Kasting, J. F. Using biogenic sulfur gases as remotely detectable biosignatures on anoxic planets. Astrobiology 11, 419–441 (2011).

    ADS  Google Scholar 

  62. Neale, R. B. et al. Description of the NCR Community Atmosphere Model (CAM 5.0) Technical Note NCAR/TN-486+ STR (NCAR, 2010).

  63. Zhang, M., Lin, W., Bretherton, C. S., Hack, J. J. & Rasch, P. J. A modified formulation of fractional stratiform condensation rate in the NCAR Community Atmospheric Model (CAM2). J. Geophys. Res. Atmos. 108, 4035 (2003).

    ADS  Google Scholar 

  64. Zhang, G. J. & McFarlane, N. A. Sensitivity of climate simulations to the parameterization of cumulus convection in the Canadian climate centre general circulation model. Atmos. Ocean 33, 407–446 (1995).

    Google Scholar 

  65. Hack, J. J. Parameterization of moist convection in the National Center for Atmospheric Research Community Climate Model (CCM2). J. Geophys. Res. 99, 5551–5568 (1994).

    ADS  Google Scholar 

  66. Kinnison, D. E. et al. Sensitivity of chemical tracers to meteorological parameters in the MOZART-3 chemical transport model. J. Geophys. Res. Atmos. 112, D20302 (2007).

    ADS  Google Scholar 

  67. Montgomery, A. & Holloway, T. Assessing the relationship between satellite-derived NO2 and economic growth over the 100 most populous global cities. J. Appl. Remote Sensing 12, 042607 (2018).

    ADS  Google Scholar 

  68. Yates, J. S. et al. Ozone chemistry on tidally locked M dwarf planets. Mon. Not. R. Astron. Soc. 492, 1691–1705 (2020).

    ADS  Google Scholar 

  69. Yang, J., Abbot, D. S., Koll, D. D. B., Hu, Y. & Showman, A. P. Ocean dynamics and the inner edge of the habitable zone for tidally locked terrestrial planets. Astrophys. J. 871, 29 (2019).

    ADS  Google Scholar 

  70. Salazar, A. M., Olson, S. L., Komacek, T. D., Stephens, H. & Abbot, D. S. The effect of substellar continent size on ocean dynamics of Proxima Centauri b. Astrophys. J. Lett. 896, L16 (2020).

    ADS  Google Scholar 

  71. Del Genio, A. D. et al. Habitable climate scenarios for Proxima Centauri b with a dynamic ocean. Astrobiology 19, 99–125 (2019).

    ADS  Google Scholar 

  72. Gray, R. O. et al. Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc—the southern sample. Astron. J. 132, 161–170 (2006).

    ADS  Google Scholar 

  73. Schmidt, S. J., Cruz, K. L., Bongiorno, B. J., Liebert, J. & Reid, I. N. Activity and kinematics of ultracool dwarfs, including an amazing flare observation. Astron. J. 133, 2258–2273 (2007).

    ADS  Google Scholar 

  74. Kopparapu, R. K. et al. The inner edge of the habitable zone for synchronously rotating planets around low-mass stars using general circulation models. Astrophys. J. 819, 84 (2016).

    ADS  Google Scholar 

  75. Poulsen, C. J., Tabor, C. & White, J. D. Long-term climate forcing by atmospheric oxygen concentrations. Science 348, 1238–1241 (2015).

    ADS  Google Scholar 

  76. Payne, R. C., Britt, A. V., Chen, H., Kasting, J. F. & Catling, D. C. The response of Phanerozoic surface temperature to variations in atmospheric oxygen concentration. J. Geophys. Res. Atmos. 121, 10089–10096 (2016).

    ADS  Google Scholar 

  77. Wade, D. C. et al. Simulating the climate response to atmospheric oxygen variability in the Phanerozoic: a focus on the Holocene, Cretaceous and Permian. Clim. Past 15, 1463–1483 (2019).

    Google Scholar 

  78. Wolf, E. T., Kopparapu, R. K. & Haqq-Misra, J. Simulated phase-dependent spectra of terrestrial aquaplanets in M dwarf systems. Astrophys. J. 877, 35 (2019).

    ADS  Google Scholar 

  79. Roble, R. G. & Ridley, E. C. A thermosphere-ionosphere-mesosphere-electrodynamics general circulation model (time-GCM): equinox solar cycle minimum simulations (30–500 km). Geophys. Res. Lett. 21, 417–420 (1994).

    ADS  Google Scholar 

  80. Banks, P. M. & Kockarts, G. in Aeronomy: Part B Ch.15 (Elsevier, 1973).

  81. Collins, W. D. et al. The Community Climate System Model version 3 (CCSM3). J. Clim. 19, 2122–2143 (2006).

    ADS  Google Scholar 

  82. Fomichev, V., Blanchet, J.-P. & Turner, D. Matrix parameterization of the 15 μm CO2 band cooling in the middle and upper atmosphere for variable CO2 concentration. J. Geophys. Res. Atmos. 103, 11505–11528 (1998).

    ADS  Google Scholar 

  83. Lean, J. Evolution of the Sun’s spectral irradiance since the Maunder minimum. Geophys. Res. Lett. 27, 2425–2428 (2000).

    ADS  Google Scholar 

  84. Solomon, S. C. & Qian, L. Solar extreme-ultraviolet irradiance for general circulation models. J. Geophys. Res. Space Phys. 110, A10306 (2005).

    ADS  Google Scholar 

  85. Wang, Y.-M., Lean, J. L. & Sheeley, N. R.Jr. Modeling the sun’s magnetic field and irradiance since 1713. Astrophys. J. 625, 522 (2005).

    ADS  Google Scholar 

  86. Kopparapu, R. K. et al. Habitable moist atmospheres on terrestrial planets near the inner edge of the habitable zone around M dwarfs. Astrophys. J. 845, 5 (2017).

    ADS  Google Scholar 

  87. López-Puertas, M. et al. Observation of NOx enhancement and ozone depletion in the Northern and Southern Hemispheres after the October-November 2003 solar proton events. J. Geophys. Res. Space Phys. 110, A09S43 (2005).

    Google Scholar 

  88. Jackman, C. et al. Short-and medium-term atmospheric constituent effects of very large solar proton events. Atmos. Chem. Phys. 8, 765–785 (2008).

    ADS  Google Scholar 

  89. Loyd, R. O. P. et al. The MUSCLES Treasury Survey. III. X-Ray to infrared spectra of 11 M and K stars hosting planets. Astrophys. J. 824, 102 (2016).

    ADS  Google Scholar 

  90. Youngblood, A. et al. The MUSCLES Treasury Survey. II. Intrinsic Lyα and extreme ultraviolet spectra of K and M dwarfs with exoplanets*. Astrophys. J. 824, 101 (2016).

    ADS  Google Scholar 

  91. Husser, T.-O. et al. A new extensive library of PHOENIX stellar atmospheres and synthetic spectra. Astron. Astrophys. 553, A6 (2013).

    Google Scholar 

  92. Turbet, M., Bourrier, V. & Leconte, J. A review of possible planetary atmospheres in the TRAPPIST-1 system. Space Sci. Rev. 216, 100 (2020).

    ADS  Google Scholar 

  93. Candelaresi, S., Hillier, A., Maehara, H., Brand enburg, A. & Shibata, K. Superflare occurrence and energies on G-, K-, and M-type dwarfs. Astrophys. J. 792, 67 (2014).

    ADS  Google Scholar 

  94. Kay, C., Airapetian, V. S., Lüftinger, T. & Kochukhov, O. Frequency of coronal mass ejection impacts with early terrestrial planets and exoplanets around active solar-like stars. Astrophys. J. Lett. 886, L37 (2019).

    ADS  Google Scholar 

  95. Hawley, S. L. et al. Kepler flares. I. Active and inactive M dwarfs. Astrophys. J. 797, 121 (2014).

    ADS  Google Scholar 

  96. Kowalski, A. F. et al. Time-resolved properties and global trends in dMe flares from simultaneous photometry and spectra. Astrophys. J Suppl. Ser. 207, 15 (2013).

    ADS  Google Scholar 

  97. Loyd, R. O. P. et al. HAZMAT. IV. Flares and superflares on young M stars in the far ultraviolet. Astrophys. J. 867, 70 (2018).

    ADS  Google Scholar 

  98. Froning, C. S. et al. A hot ultraviolet flare on the M dwarf star GJ 674. Astrophys. J. Lett. 871, L26 (2019).

    ADS  Google Scholar 

  99. Hilton, E. J. The Galactic M Dwarf Flare Rate. PhD thesis, Univ. Washington (2011).

  100. Feinstein, A., Montet, B. & Ansdell, M. stella: convolutional neural networks for flare identification in TESS. J. Open Source Softw. 5, 2347 (2020).

    ADS  Google Scholar 

  101. Güdel, M., Audard, M., Reale, F., Skinner, S. L. & Linsky, J. L. Flares from small to large: X-ray spectroscopy of Proxima Centauri with XMM-Newton. Astron. Astrophys. 416, 713–732 (2004).

    ADS  Google Scholar 

  102. Stelzer, B., Schmitt, J. H. M. M., Micela, G. & Liefke, C. Simultaneous optical and X-ray observations of a giant flare on the ultracool dwarf LP 412-31. Astron. Astrophys. 460, L35–L38 (2006).

    ADS  Google Scholar 

  103. Gopalswamy, N. et al. Properties of ground level enhancement events and the associated solar eruptions during solar cycle 23. Space Sci. Rev. 171, 23–60 (2012).

    ADS  Google Scholar 

  104. Sinnhuber, M., Nieder, H. & Wieters, N. Energetic particle precipitation and the chemistry of the mesosphere/lower thermosphere. Surv. Geophys. 33, 1281–1334 (2012).

    ADS  Google Scholar 

  105. Franciosini, E., Pallavicini, R. & Tagliaferri, G. BeppoSAX observation of a large long-duration X-ray flare from UX Arietis. Astron. Astrophys. 375, 196–204 (2001).

    ADS  Google Scholar 

  106. Ejzak, L. M., Melott, A. L., Medvedev, M. V. & Thomas, B. C. Terrestrial consequences of spectral and temporal variability in ionizing photon events. Astrophys. J. 654, 373–384 (2007).

    ADS  Google Scholar 

  107. Pettit, J. et al. Effects of the September 2005 solar flares and solar proton events on the middle atmosphere in WACCM. J. Geophys. Res. Space Phys. 5747–5763 (2018).

  108. Belov, A., Garcia, H., Kurt, V., Mavromichalaki, H. & Gerontidou, M. Proton enhancements and their relation to the x-ray flares during the three last solar cycles. Solar Phys. 229, 135–159 (2005).

    ADS  Google Scholar 

  109. Cliver, E. W., Ling, A. G., Belov, A. & Yashiro, S. Size distributions of solar flares and solar energetic particle events. Astrophys. J. Lett. 756, L29 (2012).

    ADS  Google Scholar 

  110. Herbst, K., Papaioannou, A., Banjac, S. & Heber, B. From solar to stellar flare characteristics. On a new peak size distribution for G-, K-, and M-dwarf star flares. Astron. Astrophys. 621, A67 (2019).

    ADS  Google Scholar 

  111. Jacob, D. J. Introduction to Atmospheric Chemistry (Princeton Univ. Press, 1999).

  112. Ball, S. Atmospheric Chemistry at Night ECGEB No. 3 (RSC, 2014); https://go.nature.com/3lryV6G

  113. Porter, H. S., Jackman, C. H. & Green, A. E. S. Efficiencies for production of atomic nitrogen and oxygen by relativistic proton impact in air. J. Chem. Phys. 65, 154–167 (1976).

    ADS  Google Scholar 

  114. Scheucher, M. et al. New insights into cosmic-ray-induced biosignature chemistry in Earth-like atmospheres. Astrophys. J. 863, 6 (2018).

    ADS  Google Scholar 

  115. Herbst, K. et al. A new model suite to determine the influence of cosmic rays on (exo)planetary atmospheric biosignatures. Validation based on modern Earth. Astron. Astrophys. 631, A101 (2019).

    Google Scholar 

  116. Kempton, E. M.-R., Bean, J. L. & Parmentier, V. An observational diagnostic for distinguishing between clouds and haze in hot exoplanet atmospheres. Astrophys. J. Lett. 845, L20 (2017).

    ADS  Google Scholar 

  117. Miller-Ricci, E., Meyer, M. R., Seager, S. & Elkins-Tanton, L. On the emergent spectra of hot protoplanet collision afterglows. Astrophys. J. 704, 770–780 (2009).

    ADS  Google Scholar 

  118. Gordon, I. E. et al. The HITRAN2016 molecular spectroscopic database. J. Quant. Spectrosc. Rad. Transfer 203, 3–69 (2017).

    ADS  Google Scholar 

  119. Bernath, P. F. et al. Atmospheric chemistry experiment (ace): mission overview. Geophys. Res. Lett. 32, L15S01 (2005).

    Google Scholar 

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Acknowledgements

H.C. and D.E.H. acknowledge support from the Future Investigators in NASA Earth and Space Science and Technology (FINESST) Graduate Research Award Number 80NSSC19K1523. H.C. thanks P. Loyd for assistance in the use of his MUSCLES flare code and for sharing it with the public. Z.Z. acknowledges support from the MIT BOSE Fellow programme, the Change Happens Foundation and the Heising-Simons Foundation. E.T.W. acknowledges support from NASA Habitable Worlds grant number 80NSSC17K0257. A.D.F. acknowledges support from NSF Graduate Research Fellowship Program grant number DGE-1746045. We thank A. Gu for ozone variability analysis inspiration and the QUEST high-performance computing facility at Northwestern University for computational and staff resources. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the funding agencies. This paper includes data collected by the TESS mission. Funding for the TESS mission is provided by the NASA Explorer Program. TESS data were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract number NAS5-26555. Support for MAST is provided by the NASA Office of Space Science via grant number NNX13AC07G and by other grants and contracts.

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Authors and Affiliations

  1. Center for Interdisciplinary Exploration & Research in Astrophysics (CIERA), Evanston, IL, USA

    Howard Chen & Daniel E. Horton

  2. Department of Earth and Planetary Sciences, Northwestern University, Evanston, IL, USA

    Howard Chen & Daniel E. Horton

  3. Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA

    Zhuchang Zhan

  4. Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, USA

    Allison Youngblood & Eric T. Wolf

  5. NASA Nexus for Exoplanet System Science Virtual Planetary Laboratory, Seattle, WA, USA

    Eric T. Wolf

  6. Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL, USA

    Adina D. Feinstein

Authors
  1. Howard Chen
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  2. Zhuchang Zhan
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  3. Allison Youngblood
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  4. Eric T. Wolf
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Contributions

H.C., E.T.W. and D.E.H. conceived and designed the study. H.C. conducted the numerical model simulations and data analysis. Z.Z. performed the radiative transfer model simulations. A.Y. provided stellar input data from the MUSCLES and Mega-MUSCLES surveys. A.D.F. performed the machine learning TESS data reductions. H.C. wrote the manuscript with input from all co-authors.

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Correspondence to Howard Chen.

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Peer review information Nature Astronomy thanks Antigona Segura and Eric Hébrard for their contribution to the peer review of this work.

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Extended data

Extended Data Fig. 1 Input broadband (a) and UV (b) spectral energy distributions for the Sun, HD85512, and TRAPPIST-1.

The Sun represents the G-star archetype, HD85512 a K-star, and TRAPPIST-1 a late M-star. We refer to the stellar spectral types these stars represent (G-star, K-star, and M-star) instead of the specific star in the main text and throughout the paper.

Extended Data Fig. 2 Timeseries of TESS lightcurves used in this study.

The stellar data used are those of TIC 671393 (a) and TIC 1636399 (b), showing identified flares by orange ‘ × ’s. Flares are identified by a convolutional neural network algorithm described in Feinstein et al. (2020).

Extended Data Fig. 3 Three scenarios of input vertical-mean ionization rates to explore the effects of flare frequency.

Three different assumptions are investigated: α = 0.7, 0.82, 0.54. Supplementary Table 1 lists the specific experiments and their assumed flare frequency.

Extended Data Fig. 4 Spatial and temporal atmospheric effects of repeated stellar flaring on an M-star planet.

Simulated global time slice distributions of upper atmospheric NO (a-d), OH (e-h), and O3 (i-l) concentrations and their global average time-series (m) that result from exposure to flares with time-evolving proton fluences (n). The simulated planet rotates around M-star TRAPPIST-1 synchronously and has a weak magnetic field. and OH mixing ratios are reported at 0.1 hPa, whereas O3 mixing ratios are reported at 1.0 hPa. Spherical projections are centered on 40∘ N latitude and 225∘ longitude. Red cross denotes the substellar point.

Extended Data Fig. 5 Temporal evolution of global-mean mixing ratios of NO, OH, and O3 experiencing TESS flares.

Result demonstrate that small flares over a short timespan do not substantially affect exoplanetary atmospheres. NO and OH mixing ratios are reported at 0.1 hPa, whereas O3 mixing ratios are reported at 1.0 hPa.

Extended Data Fig. 6 Global-mean vertical profiles of ozone number density at three different stellar flare frequencies.

These results show the cumulative effect (300 Earth days) of repeated stellar flares. Results that assume α approaching those of observed MUSCLES stars (α = 0.7) established a new chemical equilibrium, whereas those using a values close to very active stars (α = 0.54) have their ozone layers rapidly depleted.

Extended Data Fig. 7 Zonal mean of zonal wind, O3 mixing ratios (10−8), and meridional circulation stream functions for hypothetical O2-rich planets around a G-star, K-star, and M-star as denoted.

Results demonstrate the convolved effects of dynamics and atmospheric chemistry.

Extended Data Fig. 8 NO concentration averaged over the poles (\(\left|{\rm{latitude}}\right|>6{5}^{\circ }\)) as a function of time and pressure for hypothetical O2-rich planets.

The rotation periods of these simulations are 24 hours, 92 Earth days, and 4.32 Earth days around a G-dwarf (a), K-dwarf (b), and M-dwarf (c) star. Note the log10-scale.

Supplementary information

Supplementary Information

Supplementary Tables 1 and 2.

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Chen, H., Zhan, Z., Youngblood, A. et al. Persistence of flare-driven atmospheric chemistry on rocky habitable zone worlds. Nat Astron 5, 298–310 (2021). https://doi.org/10.1038/s41550-020-01264-1

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