Talk:Resonant trans-Neptunian object

message: I think there were a few typos in the "Toward a formal definition" section, and I have attempted to fix them according to what seemed logical − but someone who is knowledgable had better check in case I've made a dog's dinner of it. The changes were
# \varpi_N \rightarrow \Omega_N in the long equation,
# Rearrangement of equations so that the last discussion of perihelion distances to Neptune referes only to a select class of resonances.
# Sign change in the resulting last equation
Deuar 18:46, 19 September 2006 (UTC)
replies: text: Thanks!. My apologies for leaving it without checking. Eurocommuter 19:54, 19 September 2006 (UTC)
thread_title:  Resonance equations 

message: The explanatory footnotes (denoted within sections by daggers and small font) appear to be argumentative and should be migrated to the Talk page, and/or their ideas should be integrated into the article text proper.  Memetics (talk) 11:39, 22 July 2009 (UTC)
replies: text: Done. If someone can improve the integration of the notes, please do. Wabbott9 (talk) 18:17, 18 December 2010 (UTC)
thread_title: Dagger Notes

message: I'm not knowledgeable enough to make the correction myself, but it sure looks like the last 4 resonances ought to be reversed.  If not, I'd appreciate knowing why.  Thanks.
66.75.198.179 (talk) 20:07, 5 August 2009 (UTC)
replies: text: It shouldn't really matter, if you know which is the "outer" and which is the "inner" body, in relation to whatever it is they both orbit around. If you're comparing the number of orbits completed per unit time, ie how many times each one much go around the central body before they end up in conjunction at the "same" place again, then the smaller number refers to the outermost member, as it will have the slower orbit. If you're comparing how long each object's "year" (or "month", for satellites) lasts, then it's the other way round, as year length is the inverse of orbital rate... The convention usually seems to be to put the smaller number first, which doesn't feel entirely natural for some reason, but there's no reason why it can't be the other way around because unless you literally don't even know the order of orbital distances you can always figure out which one is which from that. 146.199.0.251 (talk) 17:56, 27 September 2017 (UTC)
thread_title:  Correct resonances 

message: Are there any other possible resonant angles than 180°? --JorisvS (talk) 23:23, 20 September 2012 (UTC)
thread_title:  Resonant angle 

message: This pdf (p.6) gives some candidates for distant resonant SDOs, going up to the 1:18 (2002 GB32?) and 4:79 (?) resonances. (Though our article on the latter states that it is not gravitationally influenced by Neptune.) Double sharp (talk) 04:29, 9 June 2014 (UTC)
thread_title:  Very distant resonances 

message: I've created a new diagram with the distribution of all known TNOs, including the known confirmed resonances. I noticed that the article itself is based on information as old as 2008, with some of the resonances now known to be erronous (including the notable 1:5). I will try to rewrite the article, but that could take some time. If somebody else comes with a better version, that would be fine, too.Renerpho (talk) 20:13, 9 August 2015 (UTC)
thread_title:  Updated graphic for TNO distribution 

message: Just looking at the "real vs coincidental" section (which seems to anthopomorphise things somewhat - there's not really anything so much as a coincidence in space, as that suggests some kind of agency in the other cases; if things are walking and quacking like ducks, then they probably are ducks, even if arrived at from totally different ancestors by a bizarre quirk of convergent evolution)... the example given for the "coincidence" that isn't *quite* 3:7, with a graph of calculated orbital libration (thus, NOT progression! just a different libration! someone messed up there, I think?) seems to show a pretty clear centreline around 2.305 to 2.310 (wheres 3:7 is 2.333). Noodling around with a calculator I find 13:30 to give a result of 2.3077, which is a more or less perfect match for the figures. But is this too extreme a figure? There seem to be others which are e.g. 6:11 or such, just a little shy of some more fundamental, simple fraction or halfway between them (1:2 or 3:5 in that case - 3:6 and 3:5 if you prefer, and 12:30/14:40 above, ie 6:10 (3:5 again) or 7:10).
I don't see why nature would abhor it particularly, it would just be less likely - ie in space terms, less common - that we might find such a thing occurring naturally, and it would be more sensitive to being fatally perturbed by novel external forces, compared to the far more common and routinely observed simple versions. But surely there might be one or two orbital pairs showing such a high numbered relationship? If you spread it out over cosmic time, even if they're far-TNO they'll have a steady, long-running "beat" in terms of their phase waveforms drifting apart, being in total opposition, then coming back together for a near-perfect repeated conjunction every 13 times one of them finishes an orbit, and every 30 times the other does. Of course as mentioned, the forces keeping them in that relationship are fairly fragile, but if enough of the dice of chance come up sixes on the next roll, they'll get to go round again, and again, until after eons something might finally knock one of them just hard enough to disrupt that.
(I've arrived here from trying to work out how to fix some very awkward wording on the Praamizus (cubewano) article, which has been with it since the page was first created for the then not-yet-named MP, saying something about it being almost a 5:3 relationship but needing 160 too many (too few?) Neptune orbits (??)... failed at figuring that out so have tried to come back to first principles in understanding what goes on with orbital resonance to interpret the known data for it and Neptune for myself and see if there's a relationship there. Depending on how the maths works out, it could realistically rate a not-too-extreme 10:17 relationship thanks to a moderate uncertainty parameter and figures for the orbital period and the semi-major axis that don't quite gel with each other... however, when we split the difference between the latter two, the strongest candidate by miles is 13:22 (a little off 2.95:5), which is a bit "high" for the ratio between one of those fundamental stats, and a bit "low" for the other, by about the same proportion. And if we trust one or other of them alone, the best candidates are either 53:90, or 59:100, which makes it look relatively tame.
So, resonances where the smaller figure is in the low teens, and/or the larger around 20 to 30... allowable? Both of these cases have an odd number for the inner cycle and an even one for the outer, and I don't know if that works as well as the reverse, but it seems to me that combining the two instead of two odd numbers (two even ones would of course decompose to one or the other anyway, as you could immediately divide them by 2) allows a more stable relationship to develop as each particular relative position around the macrocycle has an exact opposite that occurs a half-macrocycle before/after, helping to balance out the forces, particularly if the position of aphelion and perihelion are suitably tuned)146.199.0.251 (talk) 19:07, 27 September 2017 (UTC)
thread_title:  How complex a fraction might be realistic for a resonant relationship? 

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thread_title:  External links modified (January 2018) 

message: :copied from User_talk:Nrco0e#Other_resonances
Thanks for cleaning up 2002 MS4. If you know of any good, reasonably recent sources for which TNOs are resonant objects, could you add them to Resonant trans-Neptunian object? I've tagged almost all the lists as cn. — kwami (talk) 05:33, 9 November 2019 (UTC)
replies: text: Johnston's archive is the standard reference for this, giving a classification for all known TNOs. I've made a few changes, based on this, but I didn't remove the cn's yet. Renerpho (talk) 13:31, 9 November 2019 (UTC)

text: The identification of resonances is always statistical (sometimes beyond reasonable doubt). This is further complicated by the fact that many of the higher-order resonances (all but two or three of them) are temporary, stable only for a fraction of the age of the Solar System. It's not too bad though, as not a lot happens on timescales of a few million years. As a reference for the identification of resonances, the most trustworthy and thorough I know of is that by Mark Buie. You can find his assessment of 2002 MS4 here: He calculates that it is securely in the "SCATEXTD" class (scattered extended). I recently removed a couple of (non)plutinos (2004 PF115, 2004 UX10) from the plutino article, based on Buie's assessment of those objects. For comparison, a resonant object looks like this:  Renerpho (talk) 19:52, 9 November 2019 (UTC)

text: Quote from Buie's website:  Renerpho (talk) 19:54, 9 November 2019 (UTC)

text: Here is a list of object classifications by the Deep Ecliptic Survey. https://www.boulder.swri.edu/~buie/kbo/desclass.html Nrco0e  20:22, 9 November 2019 (UTC)

text: Maybe of interest in this regard is (Morbidelli, 1995), the first study of dynamics and resonances in the Kuiper belt. If you have access to that paper (it is behind a paywall, unfortunately), this also provides some background to the classification used by the Deep Ecliptic Survey and by Mark Buie, including the difference between resonances in eccentricity and those in inclination. The dynamics are complex, much more than what is currently reflected in the Wikipedia article. Renerpho (talk) 21:02, 9 November 2019 (UTC)

text: No worries! Thanks for the improvements you make! I am currently checking if Haumea is actually in resonance. I believe the information about that is outdated; if confirmed, I will remove Haumea from the list. Renerpho (talk) 21:36, 9 November 2019 (UTC)

text: The situation with Haumea is complicated. I haven't finished my simulation yet, but initial results indicate that Haumea is in resonance - temporarily. Buie only lists resonances that are stable for at least 10 Myrs. The knowledge of its orbit hasn't changed significantly since 2007; it's just that the 2007 paper and Buie do not use the same definition of what constitutes "being in resonance". I suggest to wait with adding any of this to the article at least until I can give final results. Renerpho (talk) 21:50, 9 November 2019 (UTC)
thread_title:  Up-to-date sources