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11:34
Scattering And Absorption of Light in Planetary Regoliths
Published on: July 1, 2019
Remote sensing of planetary properties and biosignatures on extrasolar terrestrial planets
David J Des Marais1, Martin O Harwit, Kenneth W Jucks
1Ames Research Center, Moffett Field, CA, USA. ddesmarais@mail.arc.nasa.gov
Astrobiology
|December 10, 2002
Summary
This study recommends mid-infrared and visible to near-infrared wavelengths for detecting exoplanets and signs of life. Key targets include oxygen, ozone, water, carbon dioxide, and methane for assessing habitability.
Area of Science:
- * Exoplanetary science
- * Astrobiology
- * Planetary science
Background:
- * NASA's Terrestrial Planet Finder (TPF) and ESA's Darwin missions aim to detect Earth-like exoplanets and search for biosignatures.
- * Understanding the spectral features of terrestrial planets is crucial for identifying habitable conditions and life beyond Earth.
- * Previous studies have focused on specific biosignatures, but a comprehensive approach across wavelength ranges is needed.
Purpose of the Study:
- * To recommend optimal wavelength ranges and spectral features for exoplanet detection missions like TPF and Darwin.
- * To assess the significance of various molecular signatures (O2, O3, H2O, CO2, CH4) as indicators of habitability and life.
- * To evaluate the utility of mid-infrared and visible to near-infrared spectra for characterizing exoplanetary atmospheres and properties.
Main Methods:
- * Analysis of known spectroscopic molecular band features of Earth, Venus, and Mars.
- * Assessment of these features in the context of potential extrasolar planetary analogs.
- * Evaluation of wavelength ranges (7-25 microns mid-IR, 0.5-1.1 microns visible to near-IR) for detecting key atmospheric components.
Main Results:
- * Recommended wavelength ranges: 7-25 microns (mid-IR) and 0.5-1.1 microns (visible to near-IR).
- * Highest priority for detection: Oxygen (O2) or its photolytic product Ozone (O3).
- * Other important indicators: Liquid water (H2O), Carbon Dioxide (CO2), and Methane (CH4), with caveats for CH4's origin.
- * Planetary size and mass are key habitability indicators, estimable in both recommended ranges.
Conclusions:
- * Both mid-IR and visible to near-IR wavelength ranges provide valuable data for biosignature detection and planetary characterization.
- * These wavelength ranges should be seriously considered for future missions like TPF and Darwin.
- * The diversity of exoplanetary characteristics may exceed that of our Solar System, necessitating broad observational capabilities.
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