Maqola

Biosignatures from Earth-Like Planets Around M Dwarfs

Antígona SeguraPresent address: Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CaliforniaJames F. KastingDepartment of Geosciences, The Pennsylvania State University, University Park, PennsylvaniaVictoria MeadowsInfrared Processing and Analysis Center, Pasadena, CaliforniaMartin CohenRadio Astronomy Laboratory, University of California, Berkeley, Berkeley, CaliforniaJohn ScaloDepartment of Astronomy, University of Texas, Austin, TexasDavid CrispMember of the NASA Astrobiology InstituteRebecca ButlerMember of the NASA Astrobiology InstituteG. TinettiMember of the NASA Astrobiology Institute

2005en

ABI

Annotatsiya

Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two observed active M dwarfs-AD Leo and GJ 643-and three quiescent model stars. The spectral distribution of these stars in the ultraviolet generates a different photochemistry on these planets. As a result, the biogenic gases CH4, N2O, and CH3Cl have substantially longer lifetimes and higher mixing ratios than on Earth, making them potentially observable by space-based telescopes. On the active M-star planets, an ozone layer similar to Earth's was developed that resulted in a spectroscopic signature comparable to the terrestrial one. The simultaneous detection of O2 (or O3) and a reduced gas in a planet's atmosphere has been suggested as strong evidence for life. Planets circling M stars may be good locations to search for such evidence.

Hali tarjima qilinmagan

Identifikatorlar

DOI: 10.1089/ast.2005.5.706

Iqtiboslar va manbalar

2 ta iqtibos0 ta foydalanilgan manba