Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Experts meet to decide Pluto fate, Finally we'll know what a 'planet' is... |
Aug 14 2006, 06:06 AM
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#1
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Member Group: Members Posts: 295 Joined: 2-March 04 From: Central California Member No.: 45 |
-------------------- Eric P / MizarKey
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Aug 16 2006, 02:33 PM
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#2
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Senior Member Group: Members Posts: 2517 Joined: 13-September 05 Member No.: 497 |
The barycenter rule is laughable, IMHO. You'd think they could have tried a little harder if the intent was to handle extrasolar double planets in the future, unless somebody had some political agenda to make Charon a planet. I'd have tried to make the minimum barycenter distance some function of the body radii so as to exclude Charon.
I also wonder how well the hydrostatic rule will work in practice around the low end, something we are likely to see either for KBOs or even for the larger asteroids. Leave it to the IAU to overcomplicate what was a seemingly simple question. -------------------- Disclaimer: This post is based on public information only. Any opinions are my own.
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Aug 16 2006, 04:25 PM
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#3
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Member Group: Members Posts: 809 Joined: 11-March 04 Member No.: 56 |
I'd have tried to make the minimum barycenter distance some function of the body radii so as to exclude Charon. Let me suggest instead that the criterion should be in terms of ratio of the smaller distance to the barycentre / the total distance between the gravitational centers of the two objects -- regardless of the radius of either of the two bodies. That ratio would be the same as the ratio of the smaller of the two bodies to the combined mass of the system. A "perfect" double planet would consist of two objects of the same mass with the barycentre halfway between them. Nobody would quarrel with that being called a double planet. A possible criterion for a double planet system might be something like: a system in which the distance from the gravitational center of the smaller body to the barycentre is at least one third of the total distance between the gravitational centers of the two bodies -- in other words, the mass of the smaller body should be at least half the mass of the larger one. |
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Aug 16 2006, 04:29 PM
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#4
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Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
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