title: Carbon Monoxide and the Potential for Prebiotic Chemistry on Habitable Planets around Main Sequence M Stars.
abstract: Lifeless planets with CO2atmospheres produce CO by CO2photolysis. On planets around M dwarfs, CO is a long-lived atmospheric compound, as long as UV emission due to the star's chromospheric activity lasts, and the sink of CO and O2in seawater is small compared to its atmospheric production. Atmospheres containing reduced compounds, like CO, may undergo further energetic and chemical processing to give rise to organic compounds of potential importance for the origin of life. We calculated the yield of organic compounds from CO2-rich atmospheres of planets orbiting M dwarf stars, which were previously simulated by Domagal-Goldman et al. (2014) and Harman et al. (2015), by cosmic rays and lightning using results of experiments by Miyakawa et al. (2002) and Schlesinger and Miller ( 1983a , 1983b ). Stellar protons from active stars may be important energy sources for abiotic synthesis and increase production rates of biological compounds by at least 2 orders of magnitude compared to cosmic rays. Simple compounds such as HCN and H2CO are more readily synthesized than more complex ones, such as amino acids and uracil (considered here as an example), resulting in higher yields for the former and lower yields for the latter. Electric discharges are most efficient when a reducing atmosphere is present. Nonetheless, atmospheres with high quantities of CO2are capable of producing higher amounts of prebiotic compounds, given that CO is constantly produced in the atmosphere. Our results further support planetary systems around M dwarf stars as candidates for supporting life or its origin. Key Words: Prebiotic chemistry-M dwarfs-Habitable planets-Cosmic rays-Lightning-Stellar activity. Astrobiology 16, 744-754.
authors.affiliation: 1 Department for Innovative Methods of Computing, ZIH, Technische Universität Dresden , Dresden, Germany .
authors.forename: J Manik
authors.initials: JM
authors.lastname: Nava-Sedeño
authors.affiliation: 2 Structural Bioinformatics and Computational Biology, BIOTEC, Technische Universität Dresden , Dresden, Germany .
authors.forename: Adrian
authors.initials: A
authors.lastname: Ortiz-Cervantes
authors.affiliation: 3 Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México , México D.F., México .
authors.forename: Antígona
authors.initials: A
authors.lastname: Segura
authors.affiliation: 4 Planetary Environments Laboratory, NASA Goddard Space Flight Center , Greenbelt, Maryland, USA .
authors.forename: Shawn D
authors.initials: SD
authors.lastname: Domagal-Goldman