Exploring extremophile gas production as a biomarker for early Earth atmospheres

Abstract Studying exoplanetary atmospheres offers critical insights into chemical compositions, temperature profiles, cloud formations and atmospheric dynamics. Carbon monoxide (CO), an important molecule in biology and astronomy, exhibits distinct spectral features and could be considered a potential biosignature. This work compares the spectral bands of gases emitted by Roseovarius sp. (obtained from the Atacama desert) and theoretical model atmospheres simulating early Earth analogs. We obtained Raman and infrared spectra of the bacteria. Theoretical model atmospheres of early Earth analogs were generated for comparative spectral analysis. The spectra of Roseovarius sp. revealed distinct vibrational modes, including CO at 5.01 $\mu $ m (1996 cm −1 ) which is considered in the context of other biogenic gases in the metabolism of Roseovarius sp. Ultracool dwarf stars, especially those of spectral type M7 and later, are prime targets for observing habitable exoplanets due to their small radii. The James Webb Space Telescope (JWST) and extremely large telescopes (ELTs) will enable the spectroscopic characterization of Earth-like planets orbiting M-dwarfs. Future studies using the JWST sensitivity models PandExo could estimate the number of transits needed to detect CO/CO 2 in rocky exoplanet atmospheres, enhancing our understanding of CO detectability.