TY - JOUR
T1 - Modelling stellar proton event-induced particle radiation dose on close-in exoplanets
AU - Atri, Dimitra
N1 - Funding Information:
The author thanks Jean-Mathias Grießmeier and the anonymous reviewer for their helpful comments on the manuscript, Allan Tylka for providing the table of SPE parameters and acknowledges the developers of GEANT4 (geant4.cern.ch) and ROOT (root.cern.ch). This work made use of the Extreme Science and Engineering Discovery Environment, supported by the National Science Foundation grant no. ACI-1053575.
Publisher Copyright:
© 2016 The Authors.
PY - 2017/2/1
Y1 - 2017/2/1
N2 - Kepler observations have uncovered the existence of a large number of close-in exoplanets and serendipitously of stellar superflares with emissions several orders of magnitude higher than those observed on the Sun. The interaction between the two and their implications on planetary habitability are of great interest to the community. Stellar proton events (SPEs) interact with planetary atmospheres, generate secondary particles and increase the radiation dose on the surface. This effect is amplified for close-in exoplanets and can be a serious threat to potential planetary life. Monte Carlo simulations are used tomodel the SPE-induced particle radiation dose on the surface of such exoplanets. The results show a wide range of surface radiation doses on planets in close-in configurations with varying atmospheric column depths, magnetic moments and orbital radii. It can be concluded that for close-in exoplanets with sizable atmospheres and magnetospheres, the radiation dose contributed by stellar superflares may not be high enough to sterilize a planet (for life as we know it) but can result in frequent extinction level events. In light of recent reports, the interaction of hard-spectrum SPEs with the atmosphere of Proxima Centauri b is modelled and their implications on its habitability are discussed.
AB - Kepler observations have uncovered the existence of a large number of close-in exoplanets and serendipitously of stellar superflares with emissions several orders of magnitude higher than those observed on the Sun. The interaction between the two and their implications on planetary habitability are of great interest to the community. Stellar proton events (SPEs) interact with planetary atmospheres, generate secondary particles and increase the radiation dose on the surface. This effect is amplified for close-in exoplanets and can be a serious threat to potential planetary life. Monte Carlo simulations are used tomodel the SPE-induced particle radiation dose on the surface of such exoplanets. The results show a wide range of surface radiation doses on planets in close-in configurations with varying atmospheric column depths, magnetic moments and orbital radii. It can be concluded that for close-in exoplanets with sizable atmospheres and magnetospheres, the radiation dose contributed by stellar superflares may not be high enough to sterilize a planet (for life as we know it) but can result in frequent extinction level events. In light of recent reports, the interaction of hard-spectrum SPEs with the atmosphere of Proxima Centauri b is modelled and their implications on its habitability are discussed.
KW - Planets and satellites: atmospheres
KW - Planets and satellites: magnetic fields
KW - Radiation mechanisms: non-thermal
KW - Stars: flare
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U2 - 10.1093/mnrasl/slw199
DO - 10.1093/mnrasl/slw199
M3 - Article
AN - SCOPUS:85019614359
SN - 1745-3925
VL - 465
SP - L34-L38
JO - Monthly Notices of the Royal Astronomical Society: Letters
JF - Monthly Notices of the Royal Astronomical Society: Letters
IS - 1
ER -