Sirius_Alpha Admin
Number of posts : 4320 Location : Earth Registration date : 2008-04-06
| Subject: Close Stellar Encounters and Planet Perturbations 21st June 2012, 8:21 pm | |
| Disrupting Primordial Planet Signatures: The Close Encounter of Two Single-Planet Exosystems in the Galactic Disc http://arxiv.org/abs/1206.4694 - Quote :
- During their main sequence lifetimes, the majority of all Galactic Disc field stars must endure at least one stellar intruder passing within a few hundred AU. Mounting observations of planet-star separations near or beyond this distance suggest that these close encounters may fundamentally shape currently-observed orbital architectures and hence obscure primordial orbital features. We consider the commonly-occurring fast close encounters of two single-planet systems in the Galactic Disc, and investigate the resulting change in the planetary eccentricity and semimajor axis. We derive explicit 4-body analytical limits for these variations and present numerical cross-sections which can be applied to localized regions of the Galaxy. We find that each wide-orbit planet has a few percent chance of escape and an eccentricity that will typically change by at least 0.1 due to these encounters. The orbital properties established at formation of millions of tight-orbit Milky Way exoplanets are likely to be disrupted.
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