Spectrum of a Habitable World: Earthshine in the Near‐Infrared

Turnbull, Margaret; Traub, Wesley A.; Jucks, K. W.; Woolf, N. J.; Meyer, Michael; Gorlova, Nadya; Skrutskie, Michael F.; Wilson, John C.

doi:10.1086/503322

Cited by 174 publications

(141 citation statements)

References 21 publications

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“…For this paper we use the US Standard Atmosphere 1976 spring-fall pressure-temperature profile, (COESA 1976;Cox 2000) and mixing ratio profiles shown in Figure 1. For further details on the model in an exoplanet context see Turnbull et al (2006) and .…”

Section: Model Descriptionmentioning

confidence: 99%

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Transits of Earth-Like Planets

Kaltenegger

Traub

2009

ApJ

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332

388

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Transmission spectroscopy of Earth-like exoplanets is a potential tool for habitability screening. Transiting planets are present-day "Rosetta Stones" for understanding extrasolar planets because they offer the possibility to characterize giant planet atmospheres and should provide an access to biomarkers in the atmospheres of Earth-like exoplanets, once they are detected. Using the Earth itself as a proxy we show the potential and limits of the transiting technique to detect biomarkers on an Earth-analog exoplanet in transit. We quantify the Earth's cross section as a function of wavelength, and show the effect of each atmospheric species, aerosol, and Rayleigh scattering. Clouds do not significantly affect this picture because the opacity of the lower atmosphere from aerosol and Rayleigh losses dominates over cloud losses. We calculate the optimum signal-tonoise ratio for spectral features in the primary eclipse spectrum of an Earth-like exoplanet around a Sun-like star and also M stars, for a 6.5 m telescope in space. We find that the signal-to-noise values for all important spectral features are on the order of unity or less per transit-except for the closest stars-making it difficult to detect such features in one single transit, and implying that coadding of many transits will be essential.

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Section: Model Descriptionmentioning

confidence: 99%

“…Our line-by-line radiative transfer code for the Earth has been validated by comparison to observed reflection and emission spectra (Woolf et al 2002;Turnbull et al 2006;Christensen & Pearl 1997;.…”

Section: Model Validationmentioning

confidence: 99%

Transits of Earth-Like Planets

Kaltenegger

Traub

2009

ApJ

Self Cite

332

388

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“…Turnbull et al 2006;Montañés-Rodríguez et al 2007). Averaged over a spatially unresolved hemisphere of Earth, the reflectivity of this spectral feature is just a few percent over the background spectrum.…”

Section: Surface Biosignaturesmentioning

confidence: 99%

Planetary targets in the search for extrasolar oxygenic photosynthesis

Cockell

Raven

Kaltenegger

et al. 2009

Plant Ecology & Diversity

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Background:In the coming decades space telescopes will be constructed that will attempt to find the gaseous products of oxygenic photosynthesis, the most promising biosignatures of life, in the atmospheres of temperate Earth-like planets orbiting distant stars. Aims: This paper aims to provide a synthesis of the range of feasible targets -either planets or their satellites -that could harbour photosynthesis. Methods: We calculated photosynthetically active radiation (PAR) fluxes on a diversity of planetary bodies including those receiving direct light from a single star, similarly to the Earth, and investigated the potential of these fluxes to support photosynthesis. Results: All main sequence stars emit radiation that is capable of supporting photosynthesis on Earth-like planets. We discuss tidally-locked M star planets as a special case. Less conventional targets for searches include large moons orbiting gas giant planets, which receive reflected light from their host planets and from the host star, planets in stable orbits in binary star systems, and the search for two planets within the same star system with photosynthetic signatures. Conclusions: A diversity of planetary bodies are targets in the search for extrasolar photosynthesis. The demonstration that many or none of these candidate planetary bodies harbour photosynthesis would be an important conclusion in understanding the evolution and prevalence of photosynthesis.

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“…For the data shown in Fig. 1 (a) is the visible earthshine spectrum (Woolf et al 2002), (b) is the near-infrared earthshine (defined as light from the Sun reflected from the Earth to the Moon and back again) spectrum (Turnbull et al 2006), and (c) is the thermal infrared spectrum of the Earth as measured by a spectrometer en route to Mars (Christensen and Pearl 1997). The data are shown in black and the Smithsonian Astrophysical Observatory model in red.…”

Section: Key Research Findingsmentioning

confidence: 99%

Background

Rouan¹

2015

Encyclopedia of Astrobiology

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Spectrum of a Habitable World: Earthshine in the Near‐Infrared

Cited by 174 publications

References 21 publications

Transits of Earth-Like Planets

Transits of Earth-Like Planets

Planetary targets in the search for extrasolar oxygenic photosynthesis

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