Biosignatures from Earth-Like Planets Around M Dwarfs

By A. Segura, J. Kasting, V. Meadows, Marvin L. Cohen, J. Scalo, David Crisp, R. A. Butler, Giovanna Tinetti. 2005

438 citations recorded by the source corpus.

Coupled one-dimensional photochemical-climate calculations have been performed for hypothetical Earth-like planets around M dwarfs. Visible/near-infrared and thermal-infrared synthetic spectra of these planets were generated to determine which biosignature gases might be observed by a future, space-based telescope. Our star sample included two observed active M dwarfs—AD Leo and GJ 643—and three quiescent model stars. The spectral distribution of these stars in the ultraviolet generates a different photochemistry on these planets. As a result, the biogenic gases CH4, N2O, and CH3Cl have substantially longer lifetimes and higher mixing ratios than on Earth, making them potentially observable by space-based telescopes. On the active M-star planets, an ozone layer similar to Earth's was developed that resulted in a spectroscopic signature comparable to the terrestrial one. The simultaneous detection of O2 (or O3) and a reduced gas in a planet's atmosphere has been suggested as strong evidence for life. Planets circling M stars may be good locations to search for such evidence. Key Words: Habitable planets—M dwarfs—Biosignatures—Biomarkers—Terrestrial Planet Finder. Astrobiology 5, 706–725.

Subfields: Astronomy and Astrophysics, Atmospheric Science, Spectroscopy

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Atmospheric Science

In Spectroscopy

Citations in the corpus

Pale Orange Dots: The Impact of Organic Haze on the Habitability and Detectability of Earthlike Exoplanets (2016, background): “Our AD Leo spectrum is discussed in Segura et al. (2005).”
The Detectability and Characterization of the TRAPPIST-1 Exoplanet Atmospheres with JWST (2019, background): “Photochemistry can have significant impacts on terrestrial atmospheric composition (Segura et al. 2005; Rugheimer et al. 2015) and haze formation (Arney et al. 2017, 2018), which can in turn modify the resultant temperature structure (Lincowski et al. 2018), impacting the predicted spectrum in both…”
Exoplanet Atmospheres: Physical Processes (2010, background): “Bursts of UV radiation due to stellar flares could be detrimental for life, but the planetʼs surface could be protected by a thick abiotic ozone layer (Segura et al. 2005), or alternatively life could survive by inhabiting only the subsurface.”
ABIOTIC O2 LEVELS ON PLANETS AROUND F, G, K, AND M STARS: POSSIBLE FALSE POSITIVES FOR LIFE? (2015, methodology): “In such cases, we have adopted the methodology of Segura et al. (2005) to manipulate the stellar spectra.”
Potential Biosignatures in Super-Earth Atmospheres (2010, methodology): “3) have a noticeable eff ct, as already noted by Segura et al. (2005).”
Spectropolarimetric signatures of Earth-like extrasolar planets (2007, background): “Model studies for albedos of vegetation on Earth-like planets around M stars have been published by Kiang et al. (2007); Segura et al. (2005); Tinetti et al. (2006c).”
The Habitability of Planets Orbiting M-dwarf Stars (2016, background): “…of life from harmful UV radiation, the lifetimes and mixing ratios of biogenic gases such as methane (CH4) in the atmospheres of M-dwarf planets (Segura et al., 2005), the spectroscopic detectability of biosignatures (Meadows et al., 2016), and the likelihood of false positives for life (Luger…”
GLIESE 581D IS THE FIRST DISCOVERED TERRESTRIAL-MASS EXOPLANET IN THE HABITABLE ZONE (2011, methodology): “For the stellar spectrum, we used the Virtual Planet Laboratory AD Leo data (Segura et al. 2005).”
Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life (2017, background): “Sulfur gases (DMS, DMDS, CH3SH) and relation to detectable C2H6.”
How to Characterize Habitable Worlds and Signs of Life (2017, background): “…and habitable worlds, single-column models use a plane-parallel approach that divides the atmosphere in layers (see, e.g., Kasting et al. 1993, Segura et al. 2005, Tinetti et al. 2006, Selsis et al. 2007, Kaltenegger et al. 2009, Rauer et al. 2011, Kopparapu et al. 2013, Rugheimer et al.…”
TRANSITS OF EARTH-LIKE PLANETS (2009, background): “Each of these is speculation, but a reasonable starting point given our current lack of knowledge of M-star planets (see Segura et al. 2005, Scalo et al. 2007).”
Spectral Evolution of an Earth-like Planet (2006, background): “Earth-like planets orbiting stars of different spectral type might evolve differently (Selsis 2000; Segura et al. 2003, 2005).”
What makes a planet habitable? (2009, background): “, the manufactured chloro-fluorocarbons (CCl2F2 and CCl3F) in our current atmosphere in the thermal infrared waveband, but their abundances are too low to be observed spectroscopically at low resolution (Segura et al. 2005).”
3D climate modeling of close-in land planets: Circulation patterns, climate moist bistability and habitability (2013, methodology): “As in Wordsworth et al. (2010), the emission spectrum of our M dwarf, Gl 581, was modeled using the Virtual Planet Laboratory AD Leo data (Segura et al. 2005).”
Habitable planets around the star Gliese 581 (2007, background): “The scaling factor for a planet with a thin atmosphere, like the modern Earth, is smaller – about 10% in terms of stellar flux, or 5% in semi-major axis (Segura et al. 2005).”
Kepler-22b: A 2.4 EARTH-RADIUS PLANET IN THE HABITABLE ZONE OF A SUN-LIKE STAR (2011, background): “This factor affects both the atmospheric composition and the chemistry of photosynthesis (Kasting et al. 1993; Heath et al. 1999; Segura et al. 2005).”