High-Energy Photon and Particle Effects on Exoplanet Atmospheres and Habitability

Left: The key X-ray to EUV spectral region computed for Proxima Centauri b and responsible for upper planetary atmospheric ionization, heating and loss. Coverage at high spectral resolution in soft X-rays is essential for understanding the EUV emission: The 30-60 Å range exhibits transitions of the same ions that dominate the shorter EUV wavelengths. Right: The soft X-ray range, highlighting in colour lines formed at temperatures below logT = 6.2 that could be observed by a sensitive soft X-ray grating spectrometer and used to measure by proxy the EUV flux.

It is now recognized that energetic stellar photon and particle radiation evaporates and erodes planetary atmospheres and controls upper atmospheric chemistry.

Key exoplanet host stars will be too faint at X-ray wavelengths for accurate characterization using existing generation and future slated X-ray telescopes. Observation of stellar coronal mass ejections and winds are also beyond current instrumentation. In line with theCommittee on an Exoplanet Science Strategy recognition that holistic observational approaches are needed, we point out here that a full understanding of exoplanet atmospheres, their evolution and determination of habitability requires a powerful high-resolution X-ray imaging and spectroscopic observatory. This is the only capability that can: (1) characterize by proxy the crucial, difficult to observe, EUV stellar flux, its history and its variations for planet hosting stars; (2) observe the stellar wind; (3) detect the subtle Doppler signatures of coronal mass ejections.

Jeremy J. Drake, Julián D. Alvarado-Gómez, Vladimir Airapetian, P. Wilson Cauley, Costanza Argiroffi, Matthew K. Browning, Damian J. Christian, Ofer Cohen, Lia Corrales, William Danchi, Miguel de Val-Borro, Chuanfei Dong, William Forman, Kevin France, Elena Gallo, Katherine Garcia-Sage, Cecilia Garraffo, Dawn M. Gelino, Guillaume Gronoff, H. Moritz Günther, Graham M. Harper, Raphaëlle D. Haywood, Margarita Karovska, Vinay Kashyap, Joel Kastner, Jinyoung Serena Kim, Maurice A. Leutenegger, Jeffrey Linsky, Mercedes López-Morales, Giusi Micela, Sofia-Paraskevi Moschou, Lidia Oskinova, Rachel A. Osten, James E. Owen, Katja Poppenhaeger, David A. Principe, John P.Pye, Salvatore Sciortino, Panayiotis Tzanavaris, Brad Wargelin, Peter J. Wheatley, Peter K. G. Williams, Elaine Winston, Scott J. Wolk
(Submitted on 29 Mar 2019)

Comments: Astro2020 Decadal Survey Science White Paper
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:1903.12338 [astro-ph.HE] (or arXiv:1903.12338v1 [astro-ph.HE] for this version)
Submission history
From: Jeremy Drake
[v1] Fri, 29 Mar 2019 03:16:17 UTC (2,911 KB)

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