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Posts Tagged ‘orbits’

Circular Orbits Identified For Small Exoplanets

June 2, 2015 1 comment

Artist's conception.  Image courtesy of NASA

Artist’s conception. Image courtesy of NASA

Viewed from above, our solar system’s planetary orbits around the sun resemble rings around a bulls-eye. Each planet, including Earth, keeps to a roughly circular path, always maintaining the same distance from the sun.

For decades, astronomers have wondered whether the solar system’s circular orbits might be a rarity in our universe. Now a new analysis suggests that such orbital regularity is instead the norm, at least for systems with planets as small as Earth.

In a paper published in the Astrophysical Journal, researchers from MIT and Aarhus University in Denmark report that 74 exoplanets, located hundreds of light-years away, orbit their respective stars in circular patterns, much like the planets of our solar system.

These 74 exoplanets, which orbit 28 stars, are about the size of Earth, and their circular trajectories stand in stark contrast to those of more massive exoplanets, some of which come extremely close to their stars before hurtling far out in highly eccentric, elongated orbits.

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Interstellar Crashes Could Throw Out Habitable Planets

August 18, 2011 Leave a comment

One of the protoplanetary disks in the Orion Nebula.

One of the protoplanetary disks in the Orion Nebula. Credit: NASA / ESA and L. Ricci (ESO)

Our solar system, where planets have a range of sizes and move in near-circular paths, may be rather unusual, according to a German-British team led by Professor Pavel Kroupa of the University of Bonn. The astronomers, who publish their model in the journal Monthly Notices of the Royal Astronomical Society, find that forming planetary systems may be knocked around by crashes with nearby clumps of material, leading to systems where planets have highly inclined orbits and where the smaller (and potentially habitable) worlds are thrown out completely.

Full Story: http://www.ras.org.uk/news-and-press/217-news2011/2002-interstellar-crashes-could-throw-out-habitable-planets