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Title: DISTINGUISHING A HYPOTHETICAL ABIOTIC PLANET–MOON SYSTEM FROM A SINGLE INHABITED PLANET

It has recently been suggested that an exomoon with a CH{sub 4} atmosphere, orbiting an abiotic Earth-mass planet with an O{sub 2}-rich atmosphere, can produce a false positive biosignature at a low–moderate spectral resolution (R = λ/Δλ ≤ 2000). If this were true, inferring the presence of life on exoplanets will be beyond our reach in the next several decades. Here we use a line-by-line radiative transfer model to compute the relevant reflection spectrum between 1 and 3.3 μm. We show that it is possible to separate the combined spectra of such planet–moon systems from an inhabited planet by multiple-band NIR observations. We suggest that future observations near the 2.3 μm CH{sub 4} absorption band at a resolution of 100 and an SNR of 10 or more may be a good way to distinguish an abiotic planet–moon system from a inhabited single planet.
Authors:
; ; ;  [1] ;  [2]
  1. Ministry of Education Key Laboratory for Earth System Modeling, Center for Earth System Science, Tsinghua University, Beijing, 100084 (China)
  2. Laboratory for Climate and Ocean-Atmosphere Sciences, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, 100871 (China)
Publication Date:
OSTI Identifier:
22518627
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 817; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTRA; DETECTION; MASS; METHANE; MOON; NEAR INFRARED RADIATION; PLANETARY ATMOSPHERES; PLANETS; RADIANT HEAT TRANSFER; REFLECTION; RESOLUTION