We study the masses and radii of 60 exoplanets smaller than 4 Earth radii with orbital periods shorter than 100 days. We find a nearly linear mass-radius relation: M/M_E= 3.17 […]
astro-ph.EP]
Posted inAstrochemistry, Astronomy & Telescopes, Beta Pictoris
Herschel HIFI observations of ionised carbon in the Pictoris debris disk
Context: The dusty debris disk around the ~20 Myr old main-sequence A-star beta Pic is known to contain gas. Evidence points towards a secondary origin of the gas as opposed […]
Posted inExtremeophiles and Extreme Environments, Habitable Zones, Microbiology & Virology
Refuges for Life and Novel Microbial Biospheres on Terrestrial Planets Near the End of Their Habitable Lifetimes
The future biosphere on Earth (as with its past) will be made up predominantly of unicellular microorganisms. Unicellular life was probably present for at least 2.5 Gyr before multicellular life […]
Posted inExoplanets, -moons, -comets, Extremeophiles and Extreme Environments, Habitable Zones
Final Signs of Life on Terrestrial Planets Near the End of Their Habitable Lifetimes
The biosignatures of life on Earth do not remain static, but change considerably over the planet’s habitable lifetime. Earth’s future biosphere, much like that of the early Earth, will consist […]
Posted inAstrochemistry, Exoplanets, -moons, -comets
Electrostatic Activation of Prebiotic Chemistry in Substellar Atmospheres
Charged dust grains in the atmospheres of exoplanets may play a key role in the formation of prebiotic molecules, necessary to the origin of life. Dust grains submerged in an […]
Posted inExoplanets, -moons, -comets, Habitable Zones
Possible Climates on Terrestrial Exoplanets
What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, […]
Posted inExoplanets, -moons, -comets, Habitable Zones
On the Radius of Habitable Planets
The conditions that a planet must fulfill to be habitable are not precisely known. However, it is comparatively easier to define conditions under which a planet is very likely not […]
Posted inExoplanets, -moons, -comets
Planet Packing in Circumbinary Systems
The recent discovery of planets orbiting main sequence binaries will provide crucial constraints for theories of binary and planet formation. The formation pathway for these planets is complicated by uncertainties […]
Posted inIcy Worlds, Panspermia
Seeding Life on the Moons of the Outer Planets via Lithopanspermia
Material from the surface of a planet can be ejected into space by a large impact, and could carry primitive life forms with it. We performed n-body simulations of such […]
Posted inExoplanets, -moons, -comets, Habitable Zones
Runaway Greenhouse Effect on Exomoons Due to Irradiation From Hot, Young Giant Planets
The Kepler space telescope has detected transits of objects as small as the Earth’s Moon, and moons as small as 0.2 Earth masses can be detected in the Kepler data […]