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Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star

Grenfell, John Lee and Grießmeier, Jean-Mathias and Patzer, Beate and Rauer, Heike and Segura, Antigona and Stadelmann, Anja and Stracke, Barbara and Titz, Ruth and von Paris, Philip (2007) Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star. Astrobiology, 7 (1), pp. 208-221. Mary Ann Liebert Inc.. DOI: 10.1089/ast.2006.0129 ISSN 1531-1074

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Abstract

Planets orbiting in the habitable zone of M dwarf stars are subject to high levels of galactic cosmic rays (GCRs), which produce nitrogen oxides (NO<sub>x</sub>) in Earth-like atmospheres. We investigate to what extent these NO<sub>Mx</sub> species may modify biomarker compounds such as ozone (O<sub>3</sub>) and nitrous oxide (N<sub>2</sub>O), as well as related compounds such as water (H<sub>2</sub>O) (essential for life) and methane (CH<sub>4</sub>) (which has both abiotic and biotic sources). Our model results suggest that such signals are robust, changing in the M star world atmospheric column due to GCR NO<sub>x</sub> effects by up to 20% compared to an M star run without GCR effects, and can therefore survive at least the effects of GCRs. We have not, however, investigated stellar cosmic rays here. CH<sub>4</sub> levels are about 10 times higher on M star worlds than on Earth because of a lowering in hydroxyl (OH) in response to changes in the ultraviolet. The higher levels of CH<sub>4</sub> are less than reported in previous studies. This difference arose partly because we used different biogenic input. For example, we employed 23% lower CH<sub>4</sub> fluxes compared to those studies. Unlike on Earth, relatively modest changes in these fluxes can lead to larger changes in the concentrations of biomarker and related species on the M star world. We calculate a CH<sub>4</sub> greenhouse heating effect of up to 4K. O<sub>3</sub> photochemistry in terms of the smog mechanism and the catalytic loss cycles on the M star world differs considerably compared with that of Earth.

Item URL in elib:https://elib.dlr.de/43897/
Document Type:Article
Title:Biomarker Response to Galactic Cosmic Ray-Induced NOx and the Methane Greenhouse Effect in the Atmosphere of an Earthlike Planet Orbiting an M-Dwarf Star
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Grenfell, John LeeUNSPECIFIEDUNSPECIFIED
Grießmeier, Jean-MathiasTechnische Universität BraunschweigUNSPECIFIED
Patzer, BeateTechnische Universität Berlin, Zentrum für Astronomie & AstrophysikUNSPECIFIED
Rauer, HeikeUNSPECIFIEDUNSPECIFIED
Segura, AntigonaDepartment of Geosciences, Pennsylvania State UniversityUNSPECIFIED
Stadelmann, AnjaTechnische Universität BraunschweigUNSPECIFIED
Stracke, BarbaraUNSPECIFIEDUNSPECIFIED
Titz, RuthUNSPECIFIEDUNSPECIFIED
von Paris, PhilipUNSPECIFIEDUNSPECIFIED
Date:2007
Journal or Publication Title:Astrobiology
Open Access:No
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:Yes
Volume:7
DOI :10.1089/ast.2006.0129
Page Range:pp. 208-221
Publisher:Mary Ann Liebert Inc.
ISSN:1531-1074
Status:Published
Keywords:Biomarker, Exoplanets, Atmospheres, M dwarfs, Galactic cosmic rays, greenhouse effect
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EW - Erforschung des Weltraums
DLR - Research area:Space
DLR - Program:W EW - Erforschung des Weltraums
DLR - Research theme (Project):W - Vorhaben Extrasolare Planeten (old)
Location: Berlin-Adlershof
Institutes and Institutions:Institute of Planetary Research > Extrasolar Planets and Atmospheres
Deposited By: Hedelt, Pascal
Deposited On:09 Jul 2007
Last Modified:06 Sep 2019 15:23

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