<i>Darwin</i>—A Mission to Detect and Search for Life on Extrasolar Planets

Cockell, Charles S.; Léger, Alain; Fridlund, M.; Herbst, Tom; Kaltenegger, Lisa; Absil, Olivier; Beichman, Charles; Benz, W.; Blanc, Michel; Brack, Andrè; Chelli, A.; Colangeli, L.; Cottin, Hervé; Foresto, F. Coudé du; Danchi, W. C.; Defrère, Denis; Herder, J. W. den; Eiroa, C.; Greaves, J. S.; Henning, Thomas; Johnston, K. J.; Jones, H. R. A.; Labadie, Lucas; Lämmer, H.; Launhardt, R.; Lawson, Peter R.; Lay, Oliver P.; LeDuigou, J. M.; Liseau, R.; Malbet, Fabien; Martin, Stefan; Mawet, Dimitri; Mourard, D.; Moutou, C.; Mugnier, Laurent M.; Ollivier, M.; Paresce, Francesco; Quirrenbach, A.; Rabbia, Y.; Raven, John A.; Röttgering, H. J. A.; Rouan, D.; Santos, N. C.; Selsis, F.; Serabyn, Eugene; Shibai, Hiroshi; Tamura, Motohide; Thiébaut, Éric; Westall, Francès; White, G. J.

doi:10.1089/ast.2007.0227

Cited by 112 publications

(62 citation statements)

References 110 publications

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“…Second, many more cases of planets in stellar binary systems are expected to be discovered noting that binary (and possibly multiple) stellar systems occur in high frequency in the local Galactic neighbourhood (Duquennoy & Mayor 1991;Lada 2006;Raghavan et al 2006). Moreover, orbital stability studies of planets around stars, including binary systems, are highly significant in consideration of ongoing and future planet search missions (e.g., Catanzarite et al 2006;Cockell et al 2009). …”

Section: Introductionmentioning

confidence: 99%

The instability transition for the restricted 3-body problem

Quarles

Eberle

Musielak

et al. 2011

A&A

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Aims. We establish a criterion for the stability of planetary orbits in stellar binary systems by using Lyapunov exponents and power spectra for the special case of the circular restricted 3-body problem (CR3BP). The criterion augments our earlier results given in the two previous papers of this series where stability criteria have been developed based on the Jacobi constant and the hodograph method.Methods. The centerpiece of our method is the concept of Lyapunov exponents, which are incorporated into the analysis of orbital stability by integrating the Jacobian of the CR3BP and orthogonalizing the tangent vectors via a well-established algorithm originally developed by Wolf et al. The criterion for orbital stability based on the Lyapunov exponents is independently verified by using power spectra. The obtained results are compared to results presented in the two previous papers of this series. Results. It is shown that the maximum Lyapunov exponent can be used as an indicator for chaotic behaviour of planetary orbits, which is consistent with previous applications of this method, particularly studies for the Solar System. The chaotic behaviour corresponds to either orbital stability or instability, and it depends solely on the mass ratio μ of the binary components and the initial distance ratio ρ 0 of the planet relative to the stellar separation distance. Detailed case studies are presented for μ = 0.3 and 0.5. The stability limits are characterized based on the value of the maximum Lyapunov exponent. However, chaos theory as well as the concept of Lyapunov time prevents us from predicting exactly when the planet is ejected. Our method is also able to indicate evidence of quasi-periodicity. Conclusions. For different mass ratios of the stellar components, we are able to characterize stability limits for the CR3BP based on the value of the maximum Lyapunov exponent. This theoretical result allows us to link the study of planetary orbital stability to chaos theory noting that there is a large array of literature on the properties and significance of Lyapunov exponents. Although our results are given for the special case of the CR3BP, we expect that it may be possible to augment the proposed Lyapunov exponent criterion to studies of planets in generalized stellar binary systems, which is strongly motivated by existing observational results as well as results expected from ongoing and future planet search missions.

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Section: Introductionmentioning

confidence: 99%

The instability transition for the restricted 3-body problem

Quarles

Eberle

Musielak

et al. 2011

A&A

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“…Terrestrial Planet Finder (TPF) (Marsh et al 2006;Martin et al 2007) and Darwin (Léger et al 1996;Cockell et al 2009a). The detection of life depends upon the concentration and detectability of an atmospheric constituent out of equilibrium with abiotic processes (Lovelock 1975;DesMarais et al 2002;Tinetti et al 2006;Kaltenegger and Selsis 2007;Kaltenegger et al 2009).…”

Section: Introductionmentioning

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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“…The initial idea for the Darwin mission [28,29] was proposed in 1993. It was to be composed of four or five free-flying spacecraft carrying out high-resolution imaging using nulling interferometry.…”

Section: (A) Direct Imaging Techniques: the Darwin And Terrestrial Plmentioning

confidence: 99%

High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O ₂ in exo-Earths

Snellen

2014

Phil. Trans. R. Soc. A.

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Ground-based high-dispersion spectroscopy could reveal molecular oxygen as a biomarker gas in the atmospheres of twin-Earths transiting red dwarf stars within the next 25 years. The required contrasts are only a factor of 3 lower than that already achieved for carbon monoxide in hot Jupiter atmospheres today but will need much larger telescopes because the target stars will be orders of magnitude fainter. If extraterrestrial life is very common and can therefore be found on planets around the most nearby red dwarf stars, it may be detectable via transmission spectroscopy with the next-generation extremely large telescopes. However, it is likely that significantly more collecting area is required for this. This can be achieved through the development of low-cost flux collector technology, which combines a large collecting area with a low but sufficient image quality for high-dispersion spectroscopy of bright stars.

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Darwin—A Mission to Detect and Search for Life on Extrasolar Planets

Cited by 112 publications

References 110 publications

The instability transition for the restricted 3-body problem

The instability transition for the restricted 3-body problem

Planetary targets in the search for extrasolar oxygenic photosynthesis

High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O ₂ in exo-Earths

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Darwin—A Mission to Detect and Search for Life on Extrasolar Planets

Cited by 112 publications

References 110 publications

The instability transition for the restricted 3-body problem

The instability transition for the restricted 3-body problem

Planetary targets in the search for extrasolar oxygenic photosynthesis

High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O 2 in exo-Earths

Contact Info

Product

Resources

About

High-dispersion spectroscopy of extrasolar planets: from CO in hot Jupiters to O ₂ in exo-Earths