High-resolution reflection spectra for Proxima b and Trappist-1e models for ELT observations

Abstract

The closest stars that harbor potentially habitable planets are cool M-stars. Upcoming ground- and space-based telescopes will be able to search the atmosphere of such planets for a range of chemicals. To facilitate this search and to inform upcoming observations, we model the high-resolution reflection spectra of two of the closest potentially habitable exoplanets for a range of terrestrial atmospheres and surface pressures for active and inactive phases of their host stars for both oxic and anoxic conditions: Proxima b, the closest potentially habitable exoplanet, and Trappist-1e, one of 3 Earth-size planets orbiting in the Habitable Zone of Trappist-1. We find that atmospheric spectral features, including biosignatures like O2 in combination with a reduced gas like CH4 for oxic atmospheres, as well as climate indicators like CO2 and H2O for all atmospheres, show absorption features in the spectra of Proxima b and Trappist-1e models. However for some features like oxygen, high-resolution observations will be critical to identify them in a planet's reflected flux. Thus these two planets will be among the best targets for upcoming observations of potential Earth-like planets in reflected light with planned Extremely Large Telescopes.

arXiv comment13 pages, 6 figures, 2 tables. To be published in MNRAS

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• Behind the Mask: can HARMONI@ELT detect biosignatures in the reflected light of Proxima b?
• High-Resolution Transmission Spectra of Earth through Geological Time
• Finding Signs of Life in Transit: High-resolution Transmission Spectra of Earth-like Planets around FGKM Host Stars
• Around which stars can TESS detect Earth-like planets? The Revised TESS Habitable Zone Catalog
• Influence of Biomass Emissions upon Habitability, Biosignatures and Detectability in Earth-like Atmospheres
• Densified pupil spectrograph as high-precision radial velocimetry: From direct measurement of the Universe's expansion history to characterization of nearby habitable planet candidates
• New models of reflection spectra for terrestrial exoplanets: Present and prebiotic Earth orbiting around stars of different spectral types
• An Informational-Entropic Approach to Exoplanet Characterization