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Title: Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System

Abstract

The high energy radiation environment around M dwarf stars strongly affects the characteristics of close-in exoplanet atmospheres, but these wavelengths are difficult to observe because of geocoronal and interstellar contamination. Due to these observational restrictions, a stellar atmosphere model may be used to compute the stellar extreme ultraviolet (EUV; 100–912 Å) spectrum. We construct semiempirical nonlocal thermodynamic equilibrium model spectra of the ultracool M8 star TRAPPIST-1 that span EUV to infrared wavelengths (100 Å-2.5 μm) using the atmosphere code PHOENIX. These upper atmosphere models contain prescriptions for the chromosphere and transition region and include newly added partial frequency redistribution capabilities. In the absence of broadband UV spectral observations, we constrain our models using Hubble Space Telescope Lyman α observations from TRAPPIST-1 and Galaxy Evolution Explorer UV photometric detections from a set of old M8 stars (>1 Gyr). We find that calibrating the models using both data sets separately yield similar far-ultraviolet and NUV fluxes, and EUV fluxes that range from (1.32–17.4) × 10-14 ergs s-1 cm-2. The findings from these models demonstrate that the EUV emission is very sensitive to the temperature structure in the transition region. Our lower activity models predict EUV fluxes similar to previously published estimates derivedmore » from semiempirical scaling relationships, while the highest activity model predicts EUV fluxes a factor of 10 higher. Results from this study support the idea that the TRAPPIST-1 habitable zone planets likely do not have much liquid water on their surfaces due to the elevated levels of high energy radiation emitted by the host star.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [2];  [3]; ORCiD logo [4]
  1. Univ. of Arizona, Tucson, AZ (United States)
  2. Arizona State Univ., Tempe, AZ (United States)
  3. Univ. of Hamburg (Germany)
  4. Univ. of Hamburg (Germany); Univ. of Oklahoma, Norman, OK (United States)
Publication Date:
Research Org.:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). National Energy Research Scientific Computing Center (NERSC); Univ. of California, San Diego, CA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1544081
Grant/Contract Number:  
AC03-76SF00098
Resource Type:
Accepted Manuscript
Journal Name:
The Astrophysical Journal (Online)
Additional Journal Information:
Journal Name: The Astrophysical Journal (Online); Journal Volume: 871; Journal Issue: 2; Journal ID: ISSN 1538-4357
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; stars: activity; stars: chromospheres; stars: low-mass; ultraviolet: stars

Citation Formats

Peacock, Sarah, Barman, Travis, Shkolnik, Evgenya L., Hauschildt, Peter H., and Baron, E. Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System. United States: N. p., 2019. Web. doi:10.3847/1538-4357/aaf891.
Peacock, Sarah, Barman, Travis, Shkolnik, Evgenya L., Hauschildt, Peter H., & Baron, E. Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System. United States. https://doi.org/10.3847/1538-4357/aaf891
Peacock, Sarah, Barman, Travis, Shkolnik, Evgenya L., Hauschildt, Peter H., and Baron, E. Mon . "Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System". United States. https://doi.org/10.3847/1538-4357/aaf891. https://www.osti.gov/servlets/purl/1544081.
@article{osti_1544081,
title = {Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: The TRAPPIST-1 System},
author = {Peacock, Sarah and Barman, Travis and Shkolnik, Evgenya L. and Hauschildt, Peter H. and Baron, E.},
abstractNote = {The high energy radiation environment around M dwarf stars strongly affects the characteristics of close-in exoplanet atmospheres, but these wavelengths are difficult to observe because of geocoronal and interstellar contamination. Due to these observational restrictions, a stellar atmosphere model may be used to compute the stellar extreme ultraviolet (EUV; 100–912 Å) spectrum. We construct semiempirical nonlocal thermodynamic equilibrium model spectra of the ultracool M8 star TRAPPIST-1 that span EUV to infrared wavelengths (100 Å-2.5 μm) using the atmosphere code PHOENIX. These upper atmosphere models contain prescriptions for the chromosphere and transition region and include newly added partial frequency redistribution capabilities. In the absence of broadband UV spectral observations, we constrain our models using Hubble Space Telescope Lyman α observations from TRAPPIST-1 and Galaxy Evolution Explorer UV photometric detections from a set of old M8 stars (>1 Gyr). We find that calibrating the models using both data sets separately yield similar far-ultraviolet and NUV fluxes, and EUV fluxes that range from (1.32–17.4) × 10-14 ergs s-1 cm-2. The findings from these models demonstrate that the EUV emission is very sensitive to the temperature structure in the transition region. Our lower activity models predict EUV fluxes similar to previously published estimates derived from semiempirical scaling relationships, while the highest activity model predicts EUV fluxes a factor of 10 higher. Results from this study support the idea that the TRAPPIST-1 habitable zone planets likely do not have much liquid water on their surfaces due to the elevated levels of high energy radiation emitted by the host star.},
doi = {10.3847/1538-4357/aaf891},
journal = {The Astrophysical Journal (Online)},
number = 2,
volume = 871,
place = {United States},
year = {Mon Feb 04 00:00:00 EST 2019},
month = {Mon Feb 04 00:00:00 EST 2019}
}

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Works referenced in this record:

Hazmat. i. the Evolution of Far-Uv and Near-Uv Emission from Early m Stars
journal, September 2014


PHOENIX model chromospheres of mid- to late-type M dwarfs
journal, August 2005

  • Fuhrmeister, B.; Schmitt, J. H. M. M.; Hauschildt, P. H.
  • Astronomy & Astrophysics, Vol. 439, Issue 3
  • DOI: 10.1051/0004-6361:20042338

A diagram to determine the evaporation status of extrasolar planets
journal, October 2006


XUV-driven mass loss from extrasolar giant planets orbiting active stars
journal, April 2015


Oxidant abundances in rainwater and the evolution of atmospheric oxygen
journal, October 1985

  • Kasting, James F.; Holland, Heinrich D.; Pinto, Joseph P.
  • Journal of Geophysical Research: Atmospheres, Vol. 90, Issue D6
  • DOI: 10.1029/JD090iD06p10497

Chromospheric scaling laws, width-luminosity correlations, and the Wilson-Bappu effect
journal, March 1979

  • Ayres, T. R.
  • The Astrophysical Journal, Vol. 228
  • DOI: 10.1086/156873

Multiwavelength Observations of Flares on AD Leonis
journal, November 2003

  • Hawley, Suzanne L.; Allred, Joel C.; Johns‐Krull, Christopher M.
  • The Astrophysical Journal, Vol. 597, Issue 1
  • DOI: 10.1086/378351

Semi-Empirical Modeling of the Photosphere, Chromopshere, Transition Region, and Corona of the M-Dwarf host star gj 832
journal, October 2016


Temperate Earth-sized planets transiting a nearby ultracool dwarf star
journal, May 2016

  • Gillon, Michaël; Jehin, Emmanuël; Lederer, Susan M.
  • Nature, Vol. 533, Issue 7602
  • DOI: 10.1038/nature17448

Planetary evaporation by UV and X-ray radiation: basic hydrodynamics: Planetary evaporation
journal, September 2012


Seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1
journal, February 2017

  • Gillon, Michaël; Triaud, Amaury H. M. J.; Demory, Brice-Olivier
  • Nature, Vol. 542, Issue 7642
  • DOI: 10.1038/nature21360

Strong XUV irradiation of the Earth-sized exoplanets orbiting the ultracool dwarf TRAPPIST-1
journal, October 2016

  • Wheatley, Peter J.; Louden, Tom; Bourrier, Vincent
  • Monthly Notices of the Royal Astronomical Society: Letters, Vol. 465, Issue 1
  • DOI: 10.1093/mnrasl/slw192

Reconnaissance of the TRAPPIST-1 exoplanet system in the Lyman- α line
journal, February 2017


Hydrodynamic planetary thermosphere model: 1. Response of the Earth's thermosphere to extreme solar EUV conditions and the significance of adiabatic cooling
journal, January 2008

  • Tian, Feng; Kasting, James F.; Liu, Han-Li
  • Journal of Geophysical Research, Vol. 113, Issue E5
  • DOI: 10.1029/2007JE002946

Hydrogen Lyman- α and Lyman- β spectral radiance profiles in the quiet Sun
journal, July 2009


A 3D radiative transfer framework: II. Line transfer problems
journal, March 2007


Intrinsic Colors, Temperatures, and Bolometric Corrections of Pre-Main-Sequence Stars
journal, September 2013

  • Pecaut, Mark J.; Mamajek, Eric E.
  • The Astrophysical Journal Supplement Series, Vol. 208, Issue 1
  • DOI: 10.1088/0067-0049/208/1/9

Multilevel Radiative Transfer with Partial Frequency Redistribution
journal, August 2001

  • Uitenbroek, H.
  • The Astrophysical Journal, Vol. 557, Issue 1
  • DOI: 10.1086/321659

Estimation of the XUV radiation onto close planets and their evaporation
journal, July 2011


A 3D radiative transfer framework: I. Non-local operator splitting and continuum scattering problems
journal, April 2006


THE HAWAII INFRARED PARALLAX PROGRAM. I. ULTRACOOL BINARIES AND THE L/T TRANSITION ,
journal, June 2012


HAZMAT. IV. Flares and Superflares on Young M Stars in the Far Ultraviolet
journal, November 2018

  • Parke Loyd, R. O.; Shkolnik, Evgenya L.; Schneider, Adam C.
  • The Astrophysical Journal, Vol. 867, Issue 1
  • DOI: 10.3847/1538-4357/aae2ae

METALLICITY AND TEMPERATURE INDICATORS IN M DWARF K -BAND SPECTRA: TESTING NEW AND UPDATED CALIBRATIONS WITH OBSERVATIONS OF 133 SOLAR NEIGHBORHOOD M DWARFS
journal, March 2012

  • Rojas-Ayala, Bárbara; Covey, Kevin R.; Muirhead, Philip S.
  • The Astrophysical Journal, Vol. 748, Issue 2
  • DOI: 10.1088/0004-637X/748/2/93

Modelling the chromosphere and transition region of ε Eri (K2 V)
journal, August 2005


The solar Ca II K index and the Mg II core-to-wing ratio
journal, June 1994

  • Donnelly, R. F.; White, O. R.; Livingston, W. C.
  • Solar Physics, Vol. 152, Issue 1
  • DOI: 10.1007/BF01473185

Solar Spectral Irradiance, Solar Activity, and the Near-Ultra-Violet
journal, August 2015


Partial Redistribution in Multilevel Atoms. I. Method and Application to the Solar Hydrogen Line Formation
journal, December 1995

  • Hubeny, I.; Lites, B. W.
  • The Astrophysical Journal, Vol. 455
  • DOI: 10.1086/176584

THE MUSCLES TREASURY SURVEY. II. INTRINSIC LY α AND EXTREME ULTRAVIOLET SPECTRA OF K AND M DWARFS WITH EXOPLANETS
journal, June 2016


Outer atmospheres of cool stars. XIV - A model for the chromosphere and transition region of Beta Ceti (G9.5 III)
journal, September 1983

  • Eriksson, K.; Linsky, J. L.; Simon, T.
  • The Astrophysical Journal, Vol. 272
  • DOI: 10.1086/161329

On the Age of the TRAPPIST-1 System
journal, August 2017


Stellar Lyα Emission Lines in the Hubble Space Telescope Archive: Intrinsic Line Fluxes and Absorption from the Heliosphere and Astrospheres
journal, July 2005

  • Wood, Brian E.; Redfield, Seth; Linsky, Jeffrey L.
  • The Astrophysical Journal Supplement Series, Vol. 159, Issue 1
  • DOI: 10.1086/430523

Organic haze on Titan and the early Earth
journal, November 2006

  • Trainer, M. G.; Pavlov, A. A.; DeWitt, H. L.
  • Proceedings of the National Academy of Sciences, Vol. 103, Issue 48
  • DOI: 10.1073/pnas.0608561103

Atmospheric Escape from hot Jupiters
journal, February 2009

  • Murray-Clay, Ruth A.; Chiang, Eugene I.; Murray, Norman
  • The Astrophysical Journal, Vol. 693, Issue 1
  • DOI: 10.1088/0004-637X/693/1/23

EUV-driven ionospheres and electron transport on extrasolar giant planets orbiting active stars
journal, February 2016


The Ultraviolet Radiation Environment Around m Dwarf Exoplanet host Stars
journal, January 2013


The Muscles Treasury Survey. i. Motivation and Overview
journal, March 2016

  • France, Kevin; Loyd, R. O. Parke; Youngblood, Allison
  • The Astrophysical Journal, Vol. 820, Issue 2
  • DOI: 10.3847/0004-637X/820/2/89

Including all the lines: data releases for spectra and opacities
journal, September 2017


Reconstructing the high-energy irradiation of the evaporating hot Jupiter HD 209458b
journal, September 2016

  • Louden, Tom; Wheatley, Peter J.; Briggs, Kevin
  • Monthly Notices of the Royal Astronomical Society, Vol. 464, Issue 2
  • DOI: 10.1093/mnras/stw2421

Trigonometric Parallaxes and Proper Motions of 134 Southern late m, l, and t Dwarfs from the Carnegie Astrometric Planet Search Program
journal, June 2016

  • Weinberger, Alycia J.; Boss, Alan P.; Keiser, Sandra A.
  • The Astronomical Journal, Vol. 152, Issue 1
  • DOI: 10.3847/0004-6256/152/1/24

CHIANTI - an atomic database for emission lines: I. Wavelengths greater than 50 Å
journal, October 1997

  • Dere, K. P.; Landi, E.; Mason, H. E.
  • Astronomy and Astrophysics Supplement Series, Vol. 125, Issue 1
  • DOI: 10.1051/aas:1997368

The effective temperature scale of M dwarfs
journal, July 2013


Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets
journal, August 2017


Living with a red Dwarf: Rotation and X-Ray and Ultraviolet Properties of the halo Population Kapteyn’S star
journal, April 2016


Simulated Photoevaporative mass loss from hot Jupiters in 3d
journal, July 2015

  • Tripathi, Anjali; Kratter, Kaitlin M.; Murray-Clay, Ruth A.
  • The Astrophysical Journal, Vol. 808, Issue 2
  • DOI: 10.1088/0004-637X/808/2/173

Multi-level non-LTE radiative transfer in expanding shells
journal, September 1993


CHIANTI – An atomic database for emission lines. Version 8
journal, October 2015


HAZMAT. II. Ultraviolet Variability of Low-mass Stars in the GALEX Archive
journal, July 2017


A Time-resolved Extreme-Ultraviolet Spectroscopic Study of the Quiescent and Flaring Corona of the Flare Star AU Microscopii
journal, July 1996

  • Monsignori Fossi, B. C.; Landini, M.; del Zanna, G.
  • The Astrophysical Journal, Vol. 466
  • DOI: 10.1086/177522

Pickup ion measurements by MAVEN: A diagnostic of photochemical oxygen escape from Mars: Photochemical Oxygen Escape from Mars
journal, July 2014

  • Rahmati, A.; Cravens, T. E.; Nagy, A. F.
  • Geophysical Research Letters, Vol. 41, Issue 14
  • DOI: 10.1002/2014GL060289

Water loss from terrestrial planets orbiting ultracool dwarfs: implications for the planets of TRAPPIST-1
journal, October 2016

  • Bolmont, E.; Selsis, F.; Owen, J. E.
  • Monthly Notices of the Royal Astronomical Society, Vol. 464, Issue 3
  • DOI: 10.1093/mnras/stw2578

HAZMAT. III. The UV Evolution of Mid- to Late-M Stars with GALEX
journal, February 2018


The effect of Lyman α radiation on mini-Neptune atmospheres around M stars: application to GJ 436b
journal, November 2014

  • Miguel, Yamila; Kaltenegger, Lisa; Linsky, Jeffrey L.
  • Monthly Notices of the Royal Astronomical Society, Vol. 446, Issue 1
  • DOI: 10.1093/mnras/stu2107

The Lyman-alpha line in various solar features. I - Observations
journal, June 1988

  • Fontenla, J.; Reichmann, E. J.; Tandberg-Hanssen, E.
  • The Astrophysical Journal, Vol. 329
  • DOI: 10.1086/166392

Extreme Water Loss and Abiotic O 2 Buildup on Planets Throughout the Habitable Zones of M Dwarfs
journal, February 2015


Influence of NLTE calculations on the hydrogen lines in chromospheric models
journal, June 2006


The Intrinsic Extreme Ultraviolet Fluxes of f5 v to m5 v Stars
journal, December 2013


A 3D radiative transfer framework: IV. Spherical and cylindrical coordinate systems
journal, March 2009


CHIANTI – an atomic database for emission lines: III. Continuum radiation and extension of the ion database
journal, March 1999

  • Landi, E.; Landini, M.; Dere, K. P.
  • Astronomy and Astrophysics Supplement Series, Vol. 135, Issue 2
  • DOI: 10.1051/aas:1999449

Temperate Earth-sized planets transiting a nearby ultracool dwarf star.
text, January 2016

  • Gillon, Michaël; Jehin, Emmanuël; Lederer, Susan M.
  • Apollo - University of Cambridge Repository
  • DOI: 10.17863/cam.72691

Estimation of the XUV radiation onto close planets and their evaporation
text, January 2011


The Ultraviolet Radiation Environment Around M dwarf Exoplanet Host Stars
text, January 2012


The Effective Temperature Scale of M dwarfs
text, January 2013


The Intrinsic Extreme Ultraviolet Fluxes of F5 V to M5 V Stars
text, January 2013


HAZMAT I: The Evolution of Far-UV and Near-UV Emission from Early M Stars
text, January 2014


The MUSCLES Treasury Survey I: Motivation and Overview
text, January 2016


PHOENIX model chromospheres of mid- to late-type M dwarfs
text, January 2005


Works referencing / citing this record:

Accounting for multiplicity in calculating eta Earth
journal, May 2019

  • Zink, Jon K.; Hansen, Bradley M. S.
  • Monthly Notices of the Royal Astronomical Society, Vol. 487, Issue 1
  • DOI: 10.1093/mnras/stz1246

Ly α Observations of High Radial Velocity Low-mass Stars Ross 1044 and Ross 825
journal, November 2019

  • Schneider, Adam C.; Shkolnik, Evgenya L.; Barman, Travis S.
  • The Astrophysical Journal, Vol. 886, Issue 1
  • DOI: 10.3847/1538-4357/ab48de

Identifying Candidate Atmospheres on Rocky M Dwarf Planets via Eclipse Photometry
journal, December 2019

  • Koll, Daniel D. B.; Malik, Matej; Mansfield, Megan
  • The Astrophysical Journal, Vol. 886, Issue 2
  • DOI: 10.3847/1538-4357/ab4c91

Predicting the Extreme Ultraviolet Radiation Environment of Exoplanets around Low-mass Stars: GJ 832, GJ 176, and GJ 436
journal, November 2019

  • Peacock, Sarah; Barman, Travis; Shkolnik, Evgenya L.
  • The Astrophysical Journal, Vol. 886, Issue 2
  • DOI: 10.3847/1538-4357/ab4f6f

Accounting for Multiplicity in Calculating Eta Earth
text, January 2019


Impact of Space Weather on Climate and Habitability of Terrestrial Type Exoplanets
text, January 2019