Neptune crossing KBOs |
Neptune crossing KBOs |
Oct 21 2006, 07:20 PM
Post
#1
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Question for those who might be able to work this out: How close do any known KBOs come to the orbit of Neptune. Secondarily, how close to any known KBOs come to Neptune itself? (In the usual case, with a 3:2 synchrony, the two questions might have very different answers.)
I ask partly because a close encounter could cause a KBO to take an "interesting" new orbit, flung into the inner solar system or far outwards. I ask partly to stick a needle in the Prague planet definition. |
|
|
Oct 21 2006, 08:37 PM
Post
#2
|
|
Member Group: Members Posts: 562 Joined: 29-March 05 Member No.: 221 |
Well there is at least one Neptune crossing KBO that i know of in a resonant orbit. It is designated 134340 in the MPC.
|
|
|
Oct 21 2006, 09:22 PM
Post
#3
|
|
Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
When the Minor Planet Center announces a new resonant KBO usually at the end you see a mention of how close they get to Neptune for example
QUOTE The 2/3 Neptune librators 2003 HA57, 2003 HD57, 2003 HF57, 2003 SO317, 2003 SR317, 2003 TH58, 2004 FW164 and 2005 TV189 remain more than 16, 15, 16, 17, 14, 12, 14 and 16 AU, respectively, from Neptune over a 14 000-year period. 2003 UR292 is the only one I recall with a close encounter of Neptune being mentioned QUOTE Orbital computations using the above precovery observations indicate the strong likelihood of close encounters with Neptune, well inside its sphere of influence, within a few millennia of the present time. http://cfa-www.harvard.edu/mpec/K04/K04N19.html
|
|
|
Oct 22 2006, 04:08 AM
Post
#4
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
When the Minor Planet Center announces a new resonant KBO usually at the end you see a mention of how close they get to Neptune for example 2003 UR292 is the only one I recall with a close encounter of Neptune being mentioned http://cfa-www.harvard.edu/mpec/K04/K04N19.html Thanks, Alan. That information let me find this: http://www.hohmanntransfer.com/mn/0407/24.htm The key information of which is: "Pasquale Tricarico has done a quick integration into the past and future for 2003 UR292 with his ORSA software, based on just the nominal orbit. According to his analysis, the only thing we can say so far is that 2003 UR292 is subject to periodic close approaches to Neptune, which can just perturb UR292's orbit (encounter distance at ~1 AU) or send it on a different orbit (encounter distance at ~0.3 AU), with a somewhat small ejection chance (no ejection in 2x10^5 years). " It sounds like arbitrarily close encounters can take place, meaning that just about any outcome could ensue. Note that this object has a diameter of 175 km. While the probability of Neptune flinging it at the Earth must be incredibly slim, as far as I read things, it is possible, and the key fact of that is that it makes it far, far larger than any other discovered possible Earth-impactor. Did I say "far"? Sounds like with the right introduction to the blogosphere, we've got a New York Times article on our hands. It's an understatement to say that it could cause a mass extinction event: it might cause a universal extinction event if it struck. Which is, of course, extraordinarily unlikely, but it calls to mind a Pascal's Wager type of payoff matrix (except I can't think of anything we could do to stop it if it were coming, although we would have a hell of a long warning before it arrived). Far more likely (but very unlikely still) would be that we'd get the most impressive comet ever seen if it passed through the inner solar system. Without about 100x the surface area of a typical comet nucleus, it would create an unimaginable tail. I think we'd be talking about a visual magnitude (very roughly) in the range of the full Moon. Back to my other purpose for asking: Now that we know that Neptune isn't a planet, what does it say about Terra given that an object with four times Earth's diameter (and the third largest body orbiting the Sun) is to be officially regarded a "dwarf planet"? |
|
|
Oct 22 2006, 10:53 AM
Post
#5
|
|
Senior Member Group: Members Posts: 1870 Joined: 20-February 05 Member No.: 174 |
Centaurs and KB Scattered Disk objects are the KB's equivalent of near earth asteroids and main belt asteroids that have been kicked out of resonances. There's a perennial "leakage" of objects from orbits near resonances that get tweeked into a resonance. Then it's orbital elements get "stirred with a stick" and it's long term orbital life is on the order of millions to tens of millions of years.
|
|
|
Oct 22 2006, 08:30 PM
Post
#6
|
|
Senior Member Group: Members Posts: 2920 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
Well there is at least one Neptune crossing KBO that i know of in a resonant orbit. It is designated 134340 in the MPC. You're talking about the one that has got 4 sattelites, aren't you ? So, your quote should be in the "Is 134340 a planet" thread -------------------- |
|
|
Oct 22 2006, 08:51 PM
Post
#7
|
|
Senior Member Group: Members Posts: 1887 Joined: 20-November 04 From: Iowa Member No.: 110 |
QUOTE Back to my other purpose for asking: Now that we know that Neptune isn't a planet, what does it say about Terra given that an object with four times Earth's diameter (and the third largest body orbiting the Sun) is to be officially regarded a "dwarf planet"? Don't be a lawyer. Everyone hates lawyers.
|
|
|
Oct 23 2006, 12:32 AM
Post
#8
|
|
Senior Member Group: Members Posts: 2530 Joined: 20-April 05 Member No.: 321 |
Don't be a lawyer. Everyone hates lawyers. I quite agree, figuratively speaking. But I think someone (some committee) should decide to play the game right or not at all. Not at all is my preferred course. Playing it poorly is not a good choice. "Lepton" has a perfectly fine definition. "River" hasn't had one forced onto it. "Planet" deserves no worse. |
|
|
Oct 23 2006, 10:38 AM
Post
#9
|
|
Member Group: Members Posts: 147 Joined: 14-April 06 From: Berlin Member No.: 744 |
You're talking about the one that has got 4 sattelites, aren't you ? So, your quote should be in the "Is 134340 a planet" thread FOUR satellites? I thought it had only 3... Charon, Nyx, Hydra... and?... -------------------- |
|
|
Oct 23 2006, 10:56 AM
Post
#10
|
|
Senior Member Group: Members Posts: 3648 Joined: 1-October 05 From: Croatia Member No.: 523 |
No, FOUR satellites, none of them planet: Pluto, Charon, Nix, Hydra
-------------------- |
|
|
Oct 23 2006, 11:03 AM
Post
#11
|
|
Senior Member Group: Members Posts: 2920 Joined: 14-February 06 From: Very close to the Pyrénées Mountains (France) Member No.: 682 |
FOUR satellites? I thought it had only 3... Charon, Nyx, Hydra... and?... Oups! Or may be 4th name's Ytbd*, I guess. * Yet To Be Discovered -------------------- |
|
|
Lo-Fi Version | Time is now: 3rd May 2024 - 12:30 AM |
RULES AND GUIDELINES Please read the Forum Rules and Guidelines before posting. IMAGE COPYRIGHT |
OPINIONS AND MODERATION Opinions expressed on UnmannedSpaceflight.com are those of the individual posters and do not necessarily reflect the opinions of UnmannedSpaceflight.com or The Planetary Society. The all-volunteer UnmannedSpaceflight.com moderation team is wholly independent of The Planetary Society. The Planetary Society has no influence over decisions made by the UnmannedSpaceflight.com moderators. |
SUPPORT THE FORUM Unmannedspaceflight.com is funded by the Planetary Society. Please consider supporting our work and many other projects by donating to the Society or becoming a member. |