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Habitable Zone (habitable + zone)

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Physics and Astronomy100%

Selected Abstracts

Stable satellites around extrasolar giant planets

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 3 2006
R. C. Domingos
ABSTRACT In this work, we study the stability of hypothetical satellites of extrasolar planets. Through numerical simulations of the restricted elliptic three-body problem we found the borders of the stable regions around the secondary body. From the empirical results, we derived analytical expressions of the critical semimajor axis beyond which the satellites would not remain stable. The expressions are given as a function of the eccentricities of the planet, eP, and of the satellite, esat. In the case of prograde satellites, the critical semimajor axis, in the units of Hill's radius, is given by aE, 0.4895 (1.0000 , 1.0305eP, 0.2738esat). In the case of retrograde satellites, it is given by aE, 0.9309 (1.0000 , 1.0764eP, 0.9812esat). We also computed the satellite stability region (aE) for a set of extrasolar planets. The results indicate that extrasolar planets in the habitable zone could harbour the Earth-like satellites. [source]

Stability of fictitious Trojan planets in extrasolar systems

ASTRONOMISCHE NACHRICHTEN, Issue 8 2007
R. Schwarz
Abstract Our work deals with the dynamical possibility that in extrasolar planetary systems a terrestrial planet may have stable orbits in a 1:1 mean motion resonance with a Jovian like planet. We studied the motion of fictitious Trojans around the Lagrangian points L4/L5 and checked the stability and/or chaoticity of their motion with the aid of the Lyapunov Indicators and the maximum eccentricity. The computations were carried out using the dynamical model of the elliptic restricted three-body problem that consists of a central star, a gas giant moving in the habitable zone, and a massless terrestrial planet. We found 3 new systems where the gas giant lies in the habitable zone, namely HD99109, HD101930, and HD33564. Additionally we investigated all known extrasolar planetary systems where the giant planet lies partly or fully in the habitable zone. The results show that the orbits around the Lagrangian points L4/L5 of all investigated systems are stable for long times (107 revolutions). (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Are extrasolar oceans common throughout the Galaxy?

ASTRONOMISCHE NACHRICHTEN, Issue 8 2007
D. Ehrenreich
Abstract Light and cold extrasolar planets such as OGLE 2005-BLG-390Lb, a 5.5 Earth masses planet detected via microlensing, could be frequent in the Galaxy according to some preliminary results from microlensing experiments. These planets can be frozen rocky- or ocean-planet, situated beyond the snow line and, therefore, beyond the habitable zone of their system. They can nonetheless host a layer of liquid water, heated by radiogenic energy, underneath an ice shell surface for billions of years, before freezing completely. These results suggest that oceans under ice, like those suspected to be present on icy moons in the Solar system, could be a common feature of cold low-mass extrasolar planets. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A stability catalogue of the habitable zones in extrasolar planetary systems

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007
Zs. Sándor
ABSTRACT In the near future, space missions will be launched (e.g. COROT, KEPLER) to detect Earth-like extrasolar planets. The orbital elements of these (still hypothetic) planets will contain some uncertainties that can only be eliminated by careful dynamical investigations of the hosting planetary systems. The proportion of extrasolar planetary systems with one known giant planet is high (,90 per cent). Therefore, as a first step we have investigated the possible existence of terrestrial planets in these systems. In this paper, the development of a stability catalogue of the habitable zones of exoplanetary systems is reported. This catalogue is formed by a series of stability maps, which can help to establish where Earth-like planets could exist in extrasolar planetary systems having one giant planet. After a description of the dynamical model and the numerical methods, details of the stability maps are discussed. An application of the stability catalogue to 15 known exoplanetary systems is also shown, and a characterization of the stability properties of their habitable zones is given. [source]