Dr. Caleb A. Scharf Profile

Dr. Caleb A. Scharf

Director at Columbia Univ

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Author

Publications (2)

Proceedings Article | 14 September 2006 Paper

Tidally heated moons: from icy worlds to temperate habitats

Caleb Scharf

Proceedings Volume 6309, 63090K (2006) https://doi.org/10.1117/12.680945

KEYWORDS: Planets, Satellites, Exoplanets, Stars, Liquids, Planetary systems, Information operations, Systems modeling, Solids, Jupiter

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Moons of giant planets may represent an alternative to the classical picture of habitable worlds. Within our own solar system Europa has long served as an intriguing candidate for a subsurface liquid water ocean. Sustained by tidal heating, such an ocean can exist well beyond the range at which stellar heating could raise surface temperatures to similar levels. For exoplanets, with their extraordinarily diverse orbital architectures, the same situation may arise, along with a host of other possibilities - including those where a combination of tidal and stellar heating results in water rich moons experiencing temperate surface conditions. The next generation of space-based planet finders and ground based large telescopes should begin to probe the population of moons around exoplanets - thereby opening up a new avenue in the search for life. We discuss some of these possibilities by investigating the dynamical constraints on moon systems of giant planets and by studying the characteristics of a set of 74 known extrasolar giant planets located beyond 0.6 AU from their parent stars - where moons should be long-lived with respect to removal by stellar tides. By estimating the stellar insolation that moons would experience for these exoplanet systems, and the implications for sublimation loss of volatiles, we find that between 15 and 27% of all known exoplanets may be capable of harboring small, icy, moons. In addition, by applying a simplified energy balance model, we find that some 22-28% of all known exoplanets could potentially harbor moons which, if large, could experience temperate surface conditions due to a combination of tidal and stellar heating. Large moons (0.1M_⊕), at orbital radii commensurate with those of the Galilean satellites, could maintain temperate, or habitable, surface conditions during episodes of tidal heat dissipation ranging from that seen on Europa to 10-100 times greater. We discuss the implications of these findings in the context of habitability.

Proceedings Article | 11 October 2004 Paper

Detecting the warm-hot intergalactic medium

Jan-Willem den Herder, Frits Paerels, Andrew Rasmussen, Marcel Bruijn, Henk Hoevers, Jelle Kaastra, Steven Kahn, Piet de Korte, Caleb Scharf

Proceedings Volume 5488, (2004) https://doi.org/10.1117/12.551261

KEYWORDS: Sensors, X-rays, Mirrors, Image resolution, Stars, Spatial resolution, Reflectors, Capacitance, Solids, Reflectivity

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Conference Committee Involvement (3)

Instruments, Methods, and Missions for Astrobiology XI

12 August 2008 | San Diego, California, United States

Instruments, Methods, and Missions for Astrobiology X

28 August 2007 | San Diego, California, United States

Instruments, Methods, and Missions for Astrobiology IX

14 August 2006 | San Diego, California, United States

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