Talk:Centaur (small Solar System body)

message: "Centaurs are not in stable orbits and will eventually be removed by the giant planets."    Removed to where? Could someone who knows their stuff clarify this sentence? The Singing Badger 16:15, 26 Sep 2004 (UTC)
replies: text: Centaurs will be removed from the solar system either by impacting on a planet, perturbed into a sungrazing object and destroyed by impact on or disruption by the sun (like the Kruetz family of Sun-grazing comets) or will be perturbed by one of the planets onto an orbit that will escape the solar system (the most likely removal route...).  Most asteroids and Kuiper Belt objects are on orbits which are relatively stable and will last for billions of years, orbiting far enough from the planets so that their orbits will not be drastically perturbed.  But in the case of planet crossing asteroids (like Centaurs or Earth-crossing asteroids), the planets (especially Jupiter) will cause drastic changes to the objects orbit, including total ejection from the solar system when the object passes relatively close to the planet in question.  Typical dynamical lifetimes of Centaurs are around 1 million to a few 10s of millions of years depending on the specifics of their particular orbit.  Jim 00:22, 28 Sep 2004 (UTC)
replies: text:  Cool! That's what I wanted to know. :) The Singing Badger 17:24, 28 Sep 2004 (UTC)
thread_title: Removed to where?

message: "In 2010, the New Horizons spacecraft is expected to perform a distant flyby of a centaur, (83982) 2002 GO9."
This statement was earlier removed from the New Horizons article and appears to untrue/speculation. Rmhermen 19:14, 17 January 2006 (UTC)
thread_title: Removed line

message: I got rid of the ugly red link to 10199 Chariklo in the "notable centaurs" section. I wasn't sure how much information on centaurs is appropriate to add there, so any input would be appreciated! shaggy 23:07, 1 March 2006 (UTC)
replies: text: Yes,  I believe that while the articles related to TNO/Centaurs are growing in substance we should review the distribution of the content among different articles to allow a logical, progressive digging into details while providing a quick essential read to a casual visitor. An experienced editor with not too much background in the subject would be the best, IMHO. As examples of simple common sense rules could be: let’s do not make the reader to open the link just to read the definition. Another one: if the diameter is say: 300km, let’s be nice and add whether it is huge or small for the given class of objects. Eurocommuter 11:00, 2 March 2006 (UTC)
replies: text: I think some of the more well-done KBO articles could be a good model for this. The really important things to cover (and for many of these objects, the only information available) are things like the date of it's discovery, where it orbits, and (usually) color data is pretty easy to find. 90482 Orcus is a pretty good example, I think, of a non-stub outer solar system minor planet article. shaggy 15:14, 2 March 2006 (UTC)
thread_title: 10199 Chariklo

message: This article could be expanded to include data about the color of Centaurs. Also, there's no mention of the relationship between centaurs and the Scattered Disc. Other articles on KBOs reference the "red color of KBOs and Centaurs", so there's gotta be a source for this information on wikipedia already. I would fix it now, but I don't have time. shaggy 15:18, 2 March 2006 (UTC)
replies: text: Indeed. I’m collecting some references to the articles on colour for TNO. I’ve got only tangent interest in colour, in relation to the models of the origin and classification of  TNO/centaurs but I’ll be hopefully extending this aspect in the near future. TNO/centaur connection is an interesting one and so far underexposed in our articles. Eurocommuter 17:15, 2 March 2006 (UTC)
replies: text: Also, a table of notable Centaurs similar to the list at Kuiper belt would be an excellent addition. shaggy 19:47, 2 March 2006 (UTC)
thread_title: Incomplete article

message: Is the colour section misleading to the layman? When a Centaur is described as "intensely red" do we mean that literally, or do we mean it's intense when compared to other astronomical bodies? Also, the diagram of colours shows bright purple Centaurs. Surely they're not really as purple as that? Any suggestions for how to make this clearer? The Singing Badger 12:52, 14 March 2006 (UTC)
replies: text: I understand that broadband colour indices are not equivalent of three monochromatic pictures to be combined into a natural colour, as for the fantastic satellites’ pictures for example. I have a problem how to expression the colours and perhaps I’ve exaggerated (a bit?). The problem is not simple (see colour related articles). I did indeed enhance the colours to make the point and avoid dim, dirty spheres by aligning the luminosity and ignoring the albedo. (Albedo is known only for a few of them, anyway). Pholus is indeed the most red observed object (quoted refs). I’m not so bothered with the purple, it is after all on blue/red diagonal, but I should probably add more green to have the blue less blue and more grey/blue. Please consider this as a draft. I’ll be most grateful for any technical note how to combine V-B and R-V into RGB (you probably see different colours on your monitor than me, anyway). Eurocommuter 14:06, 14 March 2006 (UTC)
replies: text:  I think saying that the colours are enhanced is all that is necessary. It looks better already. I'm afraid I can't help with the technical side. :(  The Singing Badger 14:33, 14 March 2006 (UTC)
replies: text: Well, in addition to the voluntary enhancement I found a program bug shifting the colours into hellish hues. I discovered it while my rendering of Pluto did not want to match Nasa’s idea of the hue. My apologies Eurocommuter 22:49, 16 March 2006 (UTC)
replies: text: looks much better now. I could almost believe those are the actual colors! Are you working on similar diagrams for the other TNO groups? shaggy 23:57, 16 March 2006 (UTC)
thread_title: Colours

message: Mentioning Chiron’s double life as a comet so early in the lead bothers me a lot, as it could mislead into thinking that cometary activity is typical for centaurs. (maybe it is but yet to be observed for others). Perhaps we should move it into a small subsection, further on. Eurocommuter 13:50, 14 March 2006 (UTC)
replies: text: I was thinking of trying to fit it into the physical characteristics section later today. It's really the only place I could think of to move it. I did substantially re-organize 2060 Chiron earlier, so we might think about moving most of that information over there. shaggy 13:59, 14 March 2006 (UTC)

text: Looking at it more, I think this is now one of the worst leads I have ever seen on wikipedia. I'm gonna take a crack at re-writing it. shaggy 20:09, 15 March 2006 (UTC)
thread_title:  lead; Chiron 

message: I'm wondering about the classification of the distant bodies in :Image:TheKuiperBelt_55AU_Centaurs.svg as Centaurs. (The ones that cluster just inwards of the plutinos). A lot of them look rather like TNOs to me -- They don't even cross Neptune's orbit. Take, for example, . While there is apparently no agreed-upon definition of what is a centaur and what isn't, I would have thought that you at least should be within Neptune's orbit some of the time, otherwise you're obviously a trans-neptunian object.   Is some other definition being used?  Deuar 10:16, 27 March 2006 (UTC)
replies: text: That’s an old graph…(lame excuse).Good point; I promise to check; having a heavy week in real life but I’ll look into it on Saturday. My program(s) is taking the data from MPCORB database. Back then, I did not have a module checking and correcting the types with the current MPC circular for the orbit classification (as I do now, for example in the case of the orbit plots for plutinos). I will re-generate this diagram with the current modules.Eurocommuter 18:46, 28 March 2006 (UTC)
replies: text: Indeed, MPCORB (the database,  not html on the Web) lists  as Centaur (type 10 in column 162-165 as per format description. The MPC Circular X77 I have used for other graphs does not qualify the orbit, by the way. My program followed MPC type qualification (blame yours truly, not the poor Java).  As per consensual no-nonsense definition, centaurs orbits have aCentaur < aNeptune. My apologies. Thanks Peter!  Will be fixed. Eurocommuter 20:09, 29 March 2006 (UTC)
replies: text: Funny MPCORB qualified it that way. I seem to recall they mentioned in a summary sheet somewhere that the flags they have are not to be trusted, but I didn't really believe that before ;-) This is fun isn't it! Deuar 21:40, 29 March 2006 (UTC)
replies: text: Fixed this one but a few others are affected as well.Eurocommuter 06:33, 30 March 2006 (UTC)
replies: text: Looks good. I hadn't realised that Pholus is also bigger than Chiron. Deuar 10:27, 30 March 2006 (UTC)
thread_title:  Distinguishing Centaurs from TNOs 

message: Hello Centaur enthusiasts ......
I've been studying the IAU list of Scattered Disk Objects and Centaurs, and am wondering how to tell which is which! Does anyone know the location of a simpler list which clearly designates information about ONLY Centaurs, whether officially named or not? 
Would be much appreciated.
Thanks.
Later + more searching. Check out www.zanestein.com for some great lists of information.
:C'mon, that's an astrology page.
:Anyway, a rough rule of thumb for Centaurs is that their semi-major axis is smaller than Neptune's. Deuar 18:09, 14 October 2006 (UTC)
thread_title:  Centaur list 

message: I would like to see discussions before whole sections are deleted just because there are no citations. -- Kheider 06:27, 10 October 2007 (UTC)
replies: text: The editor, Daniel Bush, made similar changes at Neptune, Asteroid, Ceres, and Small Solar System Body. He's been asked to explain these edits. --Ckatzchatspy 07:10, 10 October 2007 (UTC)
thread_title:  Deleting sections without discussion 

message: If we're just going to make up terms, we have to define them for the poor reader, who is unlikely to be an astrophysicist conversant in the latest jargon. What in blue blazes does "dynamical lifetime" mean? And while we're at it, is there really "an unstable orbital class" of minor planets or is that just bad writing?  --Milkbreath (talk) 23:58, 30 December 2008 (UTC)
replies: text: Before going into a rant, it's less embarassing to do at least a modicum of checking.   leads one rapidly to a number of explanations, including  LeadSongDog (talk) 01:36, 31 December 2008 (UTC)
replies: text: I love to rant—nobody gets hurt, do they? And I don't see how your link helps. Googling is worse than nothing, too. What you're not getting, I'm afraid, is that I don't care what it means. I do think, though, that many people who read this article will, and the article should include some way for them to find out, or, better yet, either tell them or use a phrase that's understandable on its face. I was just surfing around Wikipedia, hitting "random article" and copyediting like I do, when I stumbled upon this "centaur" business. I'm always pleased to discover a whole thing I didn't know about, and I went to copyedit when I ran into the "dynamical" wall. I've written this here in the hope that someone who knows what "dynamical lifetime" means will either tell me or fix the article. Dynamical lifetime is no help, either, by the way. I know because I tried that first. --Milkbreath (talk) 02:37, 31 December 2008 (UTC)
replies: text: Yeah, there's too big a gap between the info in that article and how we're using the phrase here. Someone correct me if I'm wrong, but I understand the dynamical lifetime to be how long a dynamic system can be expected to remain stable. None of the centaur orbits are stable over the life of the Solar system, unlike, say, Earth, which can be expected to still be here in 5 Gyrs. So yeah, the centaurs are an unstable orbital class. kwami (talk) 07:08, 31 December 2008 (UTC)
replies: text: Now, if you'd said Dynamical lifetime redirects to something off-topic, I'd have known what you meant.  If you'd deleted the redirect there would have at least been a red link to clue us in.  Anyhow, I've replaced it with an on-topic stub.LeadSongDog (talk) 20:08, 31 December 2008 (UTC)
replies: text: Now we're getting somewhere. Thing is, nobody knows what a "mean motion resonance" is. And I don't delete things I don't understand. You must be at a computer, and most computers have mice, so it was reasonable of me to suppose that anyone interested in why dynamical lifetime was of no help would have clicked on the link. Let's not fight, my son. There is science to be elucidated for the masses. --Milkbreath (talk) 20:48, 31 December 2008 (UTC)
replies: text: So who's fighting?  Fixed the red link by piping mean motion resonance to orbital mechanics.LeadSongDog (talk) 21:27, 31 December 2008 (UTC)
thread_title:  Dynamical? 

message: It seems that 2007 OR10 is classified as both an SDO and a centaur. Marginal, or do we need to address this? kwami (talk) 07:58, 11 March 2009 (UTC)
replies: text: Yes, I had noticed that in January.  But now DES is showing it as a likely 3:10 resonance.  Thanks for making me double check this.  I suspect this issue is a by-product of the very preliminary orbit.  The orbit is still poorly known (orbit quality code=5) -- Kheider (talk) 16:29, 11 March 2009 (UTC)
thread_title:  trans-Neptunian centaurs 

message: This article is shaping up nicely. Seems almost ready for FAC, I think. Serendipodous 08:14, 18 August 2009 (UTC)
replies: text: Not quite ready. It needs additional citations. And citations should use consistent format (cite templates). Images also need alt text. Ruslik_Zero 17:35, 18 August 2009 (UTC)
thread_title: FAC?

message: :  follows such a highly inclined orbit (nearly 80°) that, while it crosses from the distance of the Main belt from the Sun to past the distance of Saturn, it does not even cross Jupiter relative to the plane of Jupiter's orbit.
Does this mean that the projection of YH32's orbit onto the ecliptic is entirely within Jupiter — or something else? —Tamfang (talk) 03:04, 7 December 2010 (UTC)
thread_title:  Jove uncross'd 

message: I think the description saying "Positions of known outer solar system objects. The centaurs are those objects (in orange) that lie generally inwards of the Kuiper belt (in green) and outside the asteroid belt(pink)." From the picture it seems that the pink objects are Jupiter's Trojans, not the asteroid belt. Mr.dickens (talk) 09:03, 11 August 2011 (UTC)
replies: text: You are absolutely right! Serendipodous 17:18, 11 August 2011 (UTC)
thread_title:  Picture description Jupiter's Trojans vs. the asteroid belt 

message: Besides Chiron, just how many centaurs were named in Greek mythology? I'd bet maybe a couple of dozen at best- nowhere near the potential "44,000" bodies in the neighborhood. CFLeon (talk) 05:05, 21 January 2015 (UTC)
replies: text: Most of those 44,000 have not even been discovered, let alone have a well-determined orbit for a minor-planet number and being eligible for receiving a name. There are 297 known centaurs, of which 60 have received a number and of which just 22 have names. One of these, Hidalgo, was discovered before the centaurs were recognized as a distinct class of minor planet, and hence was not named after a centaur. --JorisvS (talk) 11:15, 21 January 2015 (UTC)
thread_title: Names

message: In the table of notable centaurs there is a field called half-life.  Can anyone please explain what this means.  The term with its relation to this topic is not explained anywhere in this article so it is not something that is understandable to the lay person outside of wild guesses.  — Preceding unsigned comment added by 173.166.173.129 (talk) 20:17, 10 July 2015 (UTC)
thread_title:  Half-Life (forward) 

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thread_title:  External links modified 

message: Hi,
why have these been removed ? They may have been in the wrong section of the article, but still they might be worth mentioning. There is a third one of this kind, also mentioned in the reference, not yet numbered, but in good-quality orbital data (uncertainty = 0):  -- Ralfkannenberg (talk) 21:46, 22 October 2018 (UTC)
replies: text: I added one of these to the discussion of retrograde orbits. WolfmanSF (talk) 01:25, 25 October 2018 (UTC)
thread_title:  Removed centaurs (342842) 2008 YB3 and (468861) 2013 LU28, including reference