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Extrasolar Planets: January 2015


Two phenomena known to inhibit the potential habitability of planets tidal forces and vigorous stellar activity might instead help chances for life on certain planets orbiting low-mass stars, University of Washington astronomers have found.

New laser-driven compression experiments reproduce the conditions deep inside exotic super-Earths and giant planet cores, and the conditions during the violent birth of Earth-like planets, documenting the material properties that determined planets' formation and evolution processes.

Small, cool planets represent the typical end-products of planetary formation. Studying the architectures of these systems, measuring planet masses and radii, and observing these planets' atmospheres during transit directly informs theories of planet assembly, migration, and evolution.

A study by astrophysicists at the University of Toronto suggests that exoplanets - planets outside our solar system - are more likely to have liquid water and be more habitable than we thought.

Future direct-imaging exoplanet missions such as WFIRST/AFTA, Exo-C, and Exo-S will measure the reflectivity of exoplanets at visible wavelengths.

To understand the evolution of planetary systems, it is important to investigate planets in highly evolved stellar systems, and to explore the implications of their observed properties with respect to potential formation scenarios.

In the solar neighborhood, where the typical relaxation timescale is larger than the cosmic age, at least 10% to 15% of Sun-like stars have planetary systems with Jupiter-mass planets. In contrast, dense star clusters, charactered by frequent close encounters, have been found to host very few planets.

Next-generation space telescopes will allow us to characterize terrestrial exoplanets. To do so effectively it will be crucial to make use of all available data.

We present an improved estimate of the occurrence rate of small planets around small stars by searching the full four-year Kepler data set for transiting planets using our own planet detection pipeline and conducting transit injection and recovery simulations to empirically measure the search completeness of our pipeline.

In this paper we present a series of models for the deep water cycle on super-Earths experiencing plate tectonics.

We present an investigation of twelve candidate transiting planets from Kepler with orbital periods ranging from 34 to 207 days, selected from initial indications that they are small and potentially in the habitable zone (HZ) of their parent stars.

Astronomers announced today that they have found eight new planets in the "Goldilocks" zone of their stars, orbiting at a distance where liquid water can exist on the planet's surface. This doubles the number of small planets (less than twice the diameter of Earth) believed to be in the habitable zone of their parent stars. Among these eight, the team identified two that are the most similar to Earth of any known exoplanets to date.

How do you make an Earth-like planet? The "test kitchen" of Earth has given us a detailed recipe, but it wasn't clear whether other planetary systems would follow the same formula.

For life as we know it to develop on other planets, those planets would need liquid water, or oceans.

The remarkable discovery of many planets and candidates using the Kepler telescope even includes ten planets orbiting eight binaries. Three out of the eight, Kepler 16, Kepler 47, and KIC 9632895, have at least one planet in the circumbinary habitable zone (BHZ).

Remarkably, this is the most compact system ever found, being characterized by a concentration of dynamically packed planets below 0.1 AU with adjacent planet pairs lying close to strong 5:4, 4:3, 5:4, and 5:4 orbital resonances.