Spectral Evolution of an Earth-like Planet

By L. Kaltenegger, Wesley A. Traub, K. Jucks. 2006

248 citations recorded by the source corpus.

We have developed a characterization of the geological evolution of the Earth's atmosphere and surface in order to model the observable spectra of an Earth-like planet through its geological history. These calculations are designed to guide the interpretation of an observed spectrum of such a planet by future instruments that will characterize exoplanets. Our models focus on planetary environmental characteristics whose resultant spectral features can be used to imply habitability or the presence of life. These features are generated by H2O, CO2, CH4, O2, O3, N2O, and vegetation-like surface albedos. We chose six geological epochs to characterize. These epochs exhibit a wide range in abundance for these molecules, ranging from a CO2-rich early atmosphere, to a CO2/CH4-rich atmosphere around 2 billion years ago, to a present-day atmosphere. We analyzed the spectra to quantify the strength of each important spectral feature in both the visible and thermal infrared spectral regions, and the resolutions required to optimally detect the features for each epoch. We find a wide range of spectral resolutions required for observing the different features. For example, H2O and O3 can be observed with relatively low resolution, while O2 and N2O require higher resolution. We also find that the inclusion of clouds in our models significantly affects both the strengths of all spectral features and the resolutions required to observe all these.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/a292f51514d1875f7d99a439943bfe98a9ff954d

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

Citations in the corpus

Exoplanet Biosignatures: A Review of Remotely Detectable Signs of Life (2017, background): “Examples of such studies include investigations of the potential atmospheric composition of the Archean Earth (Kasting, 2001; Kharecha et al., 2005; Kaltenegger et al., 2007), of planets orbiting M dwarf stars that have low UV flux (e.g., Segura et al., 2005), of possible by-products of biogenic…”
How to Characterize Habitable Worlds and Signs of Life (2017, methodology): “Bold lines show spectral resolution (λ/!λ) of 80 (visible to NIR) and 25 (IR), and high-resolution spectra are depicted in light gray.”
Chemistry of atmospheres formed during accretion of the Earth and other terrestrial planets (2009, background): “Spectral models of early Earth by Kaltenegger and colleagues (Kaltenegger et al., 2007; Kaltenegger and Sasselov, 2010) have indicated that several gas species (e.”
THE MUSCLES TREASURY SURVEY. I. MOTIVATION AND OVERVIEW (2016, background): “…Inputs FUV and NUV Irradiance: Photochemistry and Biosignatures – Spectral observations of O2, O3, CH4, and CO2, are expected to be the most important signatures of biological activity on planets with Earth-like atmospheres (Des Marais et al. 2002; Kaltenegger et al. 2007; Seager et al. 2009).”
Habitable planets around the star Gliese 581 (2007, background): “This is the purpose of future space observatories such as Darwin (Volonte et al. 2000; Kaltenegger & Fridlund 2005), TPFC (Levine et al. 2006) and TPF-I (Beichman et al. 1999).”
TRANSITS OF EARTH-LIKE PLANETS (2009, methodology): “For further details on the model in an exoplanet context see Turnbull et al. (2006) and Kaltenegger et al. (2007).”
Potential Biosignatures in Super-Earth Atmospheres (2010, unknown): “…terrestrial extra-solar planets were performed by e.g. Selsis (2000), Selsis et al. (2002), Des Marais et al. (2002), Segura et al. (2003), Segura et al. (2005), Tinetti (2006), Ehrenreich et al. (2006), Kaltenegger et al. (2007), Kaltenegger & Traub (2009) and Kaltenegger & Sasselov (2010).”