000007528 001__ 7528
000007528 005__ 20250204115239.0
000007528 0247_ $$2DOI$$a10.1051/0004-6361/202451940
000007528 037__ $$aSCART-2025-0118
000007528 100__ $$aHöning, Dennis
000007528 245__ $$aThe effect of a biosphere on the habitable timespan of stagnant-lid planets and implications for the atmospheric spectrum
000007528 260__ $$c2025
000007528 520__ $$aTemperature-dependent biological productivity controls silicate weathering and thereby extends the potential habitable timespan of Earth. Models and theoretical considerations indicate that the runaway greenhouse on Earth-like exoplanets is generally accompanied by a dramatic increase in atmospheric H2O and CO2, which might be observed with the upcoming generation of space telescopes. If an active biosphere extends the habitable timespan of exoplanets similarly to Earth, observing the atmospheric spectra of exoplanets near the inner edge of the habitable zone could then give insights into whether the planet is inhabited. Here, we explore this idea for Earth-like stagnant-lid planets. We find that while for a reduced mantle, a surface biosphere extends the habitable timespan of the planet by about 1 Gyr, for more oxidising conditions, the biologically enhanced rate of weathering becomes increasingly compensated for by an increased supply rate of CO2 to the atmosphere. Observationally, the resulting difference in atmospheric CO2 near the inner edge of the habitable zone is clearly distinguishable between biotic planets with active weathering and abiotic planets that have experienced a runaway greenhouse. For an efficient hydrological cycle, the increased bioproductivity also leads to a CH4 biosignature observable with JWST. As the planet becomes uninhabitable, the H2O infrared absorption bands dominate, but the 4.3-µm CO2 band remains a clear window into the CO2 abundances. In summary, while the effect of life on the carbonate-silicate cycle leaves a record in the atmospheric spectrum of Earth-like stagnant-lid planets, future work is needed especially to determine the tectonic state and composition of exoplanets and to push forward the development of the next generation of space telescopes.
000007528 536__ $$aFED-tWIN/$$cSTELLA/$$fPrf-2021-022
000007528 594__ $$aNO
000007528 6531_ $$aEarth
000007528 6531_ $$aplanets and satellites: atmospheres
000007528 6531_ $$aplanets and satellites: interiors 
000007528 6531_ $$aplanets and satellites: physical evolution
000007528 6531_ $$aplanets and satellites: terrestrial planets
000007528 700__ $$aCarone, Ludmila
000007528 700__ $$aBaumeister, Philipp
000007528 700__ $$aChubb, Kathy L.
000007528 700__ $$aGrenfell, John Lee
000007528 700__ $$aHakim, Kaustubh
000007528 700__ $$aIro, Nicolas
000007528 700__ $$aTaysum, Benjamin
000007528 700__ $$aTosi, Nicola
000007528 773__ $$cA205$$njan$$pAstronomy & Astrophysics$$v693$$y2025
000007528 8560_ $$fkaustubh.hakim@ksb-orb.be
000007528 85642 $$ahttps://doi.org/10.1051/0004-6361/202451940
000007528 8564_ $$s10265867$$uhttp://publi2-as.oma.be/record/7528/files/Hoening2025Biospheres.pdf
000007528 8564_ $$s3569$$uhttp://publi2-as.oma.be/record/7528/files/Hoening2025Biospheres.gif?subformat=icon$$xicon
000007528 8564_ $$s7506$$uhttp://publi2-as.oma.be/record/7528/files/Hoening2025Biospheres.jpg?subformat=icon-180$$xicon-180
000007528 905__ $$apublished in
000007528 980__ $$aREFERD