Talk:Resonant trans-Neptunian object

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This article was nominated for deletion on 20 September 2006. The result of the discussion was keep.

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2:3 resonance

(unsigned) Need some discussion about 2:3 orbits being a "well" for collecting object due to considerations of minimum energy differences and 2:3 being the first orbit has a large "out of phase" (non-interacting) aspect.

I’m not sure I understand 100% your comment (is it on the 2:3 as such or related to the Neptune migration?) but I believe both definitely belong here and will try to give progressively a more detailed account. It is not easy to write about subjects considered ‘dry’ and I’m afraid to get ‘too technical’ tag. In addition talking about resonances requires diagrams I hope I will have prepared in some time in the future but do not have right now. Without them, writing about islands of stability surrounded by chaotic regions or overlapping resonances for example is a bit tricky. Please elaborate on topics you would like to see here, or even better, please jump-start them directly in the article. Eurocommuter 19:41, 17 September 2006 (UTC)[reply]

resonance equations

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)[reply]

Thanks!. My apologies for leaving it without checking. Eurocommuter 19:54, 19 September 2006 (UTC)[reply]

Declassification of numerous numbered twotinos in MPEC 2009-G25

The most recent MPEC Circular declassifies a number of resonant objects. A hecatomb of the twotinos population: only two numbered objects are listed! Eurocommuter (talk) 09:34, 9 May 2009 (UTC)[reply]

Twotino Classifications:
Object	G25	C70	Quality	DES
(119979) 2002 WC19	Y	Y	3	2:1
(130391) 2000 JG81	Y	Y	2	2:1
(20161) 1996 TR66	N	Y	3	2:1
(26308) 1998 SM165	N	Y	3	2:1
(137295) 1999 RB216	N	Y	3	2:1

MPEC 2009-C70 (2009 Feb) did show all our numbered twotinos as 1:2. But MPEC 2009-E53 (2009 March) also shows them de-listed. I know the DES has just revised their classification scheme (hopefully for the better).

Should we list these numbered objects as potential twotinos? Perhaps something along the line of a tag that goes <ref name=C70>Potential twotino: listed as a twotino in [http://www.cfa.harvard.edu/mpec/K09/K09C70.html MPEC 2009-C70] (2009 Feb)</ref> Do we know why the MPC removed them? Are they waiting for a more accurate orbit to confirm their dynamical status? For example, 26308 (1998 SM165) has only an orbital quality of 3, yet the DES is still showing 26308 as 2:1. -- Kheider (talk) 18:38, 9 May 2009 (UTC)[reply]

I’ve never seen the MPC classification criteria and I ignore the reason of the de-listing. I was thinking to remove the de-listed from our article (updating the ref to the current MPC circular) but add a note, at the bottom of the sub-section, saying earlier listed with the ref to the older circular. I feel your idea of the table is very good but labour intensive as we should do it for all resonances.Eurocommuter (talk) 09:11, 10 May 2009 (UTC)[reply]

Since then I compared the entries for 1998 SM165 in the MPCORB database as of Oct 2008 and as of yesterday (MPEC format is defined here)

2008-10-05:

26308 5.8 0.15 K096I 37.39611 131.26248 183.09247 13.48154 0.3743936 0.00297152 47.9163398 2 MPO 13953 48 8 1982-2000 0.49 M-v 38h Marsden 000A (26308) 1998 SM165 20001003

2009-05-09

26308 5.8 0.15 K08BU 36.98188 131.04571 183.10754 13.48871 0.3738678 0.00297930 47.8328728 2 MPO 13953 48 8 1982-2000 0.49 M-v 38h Marsden 000A (26308) 1998 SM165

The semimajor axis is curiously smaller; please note that less observations have been taken into account that by DES and they stop in 2000! Consequently, I would suggest keep listing the twotinos that did not make it, following the DES orbit classification with a note about the MPEC Circular. BTW it will be a minor nightmare for me to update the diagrams next time as the update is done programmatically from the MPEC database and the Circular. Eurocommuter (talk) 09:11, 10 May 2009 (UTC)[reply]

The difference in semi-major axis could be a result of using say a 18-bit calculation instead of a 14-bit calculation. (I do not know if that is the case. I just listed it as an example.)

Other Resonant Objects missing from MPEC 2009-G25:

Plutino (84922) 2003 VS2 3:2 DES (dwarf planet candidate)

(84522) 2002 TC302 2:5 DES (large dwarf planet candidate)

(42301) 2001 UR163 4:9 DES

(79978) 1999 CC158 5:12 DES (shown, but de-listed)

I understand that high order resonances would be questioned more because Neptune would likely have weaker interactions with them. But why does the MPC list 2003 YQ179 in a high-order 1:5 resonance when even the 1:2 twotinos are being questioned? The DES lists all 3 clones of 03YQ179 as ScatNear. -- Kheider (talk) 21:17, 10 May 2009 (UTC)[reply]

MPEC 2009-J35 : DISTANT MINOR PLANETS is out. TC302 is back! :-) Of our 5 Twotinos only WC19 is missing. I get the impression that using different starting positions (different months) causes the simulation to de-list some objects. -- Kheider (talk) 16:26, 12 May 2009 (UTC)[reply]

If you look at this lists closely you'll see that objects with low solar elongation angles don't appear. I think

the idea is that these are observable objects. Andrew W 115.128.25.119 (talk) 11:18, 2 July 2010 (UTC)[reply]

I’ve included a rough description of the classification scheme from Gladman, Marsden (Arizona Book). One might speculate that MPC would follow this scheme. The key reason for the discrepancies might be the data set (apparently limited to 2000 for MPEC). Eurocommuter (talk) 12:44, 14 May 2009 (UTC)[reply]

Dagger Notes

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)[reply]

Done. If someone can improve the integration of the notes, please do. Wabbott9 (talk) 18:17, 18 December 2010 (UTC)[reply]

Correct resonances

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)ltaylor@csub.edu Larry Taylor[reply]

See Talk:Plutino#3:2_resonance_or_2:3_resonance. It is kind of like asking which way is up in space. -- Kheider (talk) 06:54, 21 June 2010 (UTC)[reply]

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)[reply]

Resonant angle

Are there any other possible resonant angles than 180°? --JorisvS (talk) 23:23, 20 September 2012 (UTC)[reply]

Very distant resonances

This pdf (p.6) gives some candidates for distant resonant SDOs, going up to the 1:18 (2002 GB₃₂?) and 4:79 ((148209) 2000 CR105?) 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)[reply]

Updated graphic for TNO distribution

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)[reply]