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To: RightWhale
I copied the data from the link you posted, and charted it as you suggested. There seemed to be little or no correlation between a planets mass, period and eccentricity.

The least massive planet was 0.1 Jupiter mass, which is to be expected based on the detection methods.

The planets of our solar system have eccentricities ranging from .01 (Venus) to .25 (Pluto). 70% of the extra-solar planets have eccentricities greater than Pluto's.

If we only compare our giant planets, with eccentricities ranging from 0.01 (Neptune) to 0.06 (Saturn ) the difference becomes more dramatic. 80% of the extra-solar planets are more eccentric than the giant planets of our system.

This suggests that our system is the exception, rather than the rule.

189 posted on 07/03/2003 6:14:08 PM PDT by e_engineer
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To: e_engineer
Thanks for taking the time for the analysis.

We might expect that systems where the main planet's orbit has high eccentricity would be tough systems to have other planets that might be interesting to us. Pluto is thought to be an escaped moon from Neptune, and Pluto's orbit takes it inside Neptune's orbit and then farther out. Right now Pluto is nearer the sun than usual so NASA wants to send a probe out there to see what is happening on Pluto when it is a little warmer.

There might be a mechanism that circularizes orbits in some systems that would be lacking in other or in most systems. Our solar system is dominated by fairly circular orbits: planets, and most moons, and the rings of Saturn and the other gas giants. It could be the interaction of several planets or moons creates the circularisation and those systems with one or two wild major planets lacks smaller rocky planets altogether. This one today might be judged to have more planets just on the basis of circular orbit of the major planet.

192 posted on 07/03/2003 7:04:41 PM PDT by RightWhale (gazing at shadows)
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To: e_engineer; RightWhale
This suggests that our system is the exception, rather than the rule.

I disagree. It is easier to detect the more elliptical orbits around other "suns" at this time.

250 posted on 07/03/2003 9:26:36 PM PDT by RadioAstronomer
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