Wikipedia:Featured article candidates/Jupiter Trojan

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The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by SandyGeorgia 23:35, 28 February 2009 [1].

Jupiter Trojan[edit]

Nominator(s): Ruslik (talk), Serendipodous (talk)

I am nominating this for featured article because the article is about a significant population of objects of the Solar System and, in my opinion, is ready to become a featured article. Ruslik (talk) 18:12, 15 February 2009 (UTC)[reply]

Comments -

Otherwise, sources look okay, links checked out with the link checker tool. Ealdgyth - Talk 14:24, 16 February 2009 (UTC)[reply]
Link was a book citation, so removed. Serendipodous 15:39, 16 February 2009 (UTC)[reply]
  • Support - Well-worked. I've helped marginally on this one, but all of my requests were fixed during PR. Good luck, again! Ceran→//forge 19:06, 16 February 2009 (UTC)[reply]
  • Support No major problems, and pointless listing minor nitpicks since going on hols shortly jimfbleak (talk) 09:49, 20 February 2009 (UTC)[reply]
  • Comments — I gave the article a quick copy edit and was pleasantly surprised at its quality. I'm not an expert in astronomy by any means, but it's excellent work as far as I could tell. I did have a few questions, however:
  • The "As of" templates appear to be capitalizing the "as". I also added January to the 2009 ones, since we're in 2009 right now, and a month helps.
    Fixed. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • In the nomenclature section, wouldn't it be better to use the names of the asteroids (including the number) rather than just the names of the people?
    Can you clarify what you mean? Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • You mention that no Lagrange asteroid was found until more than a century after Lagrange's hypothesis. Was a Trojan asteroid the first of these found? If so, I'd suggest explicitly writing that. If not, then I'd suggest removing that last sentence of the first paragraph of Observational History because it doesn't add to the understanding of this particular subject.
    Wrote explicitly. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • In the graphic of Earth's Lagrange points, are Jupiter's different in any way? If so, I'd suggest stating that they're similar in the caption. Otherwise, you don't draw any direct connection between the subject and the graphic.
    They are qualitatively similar. I added sentence to the caption. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • In this context, what does "semi-major axis" mean?
    Replaced with average radius. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • When talking about horseshoe orbits, how do we know that they can follow these orbits without having observed it? Is it mathematically derived?
    Clarified. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • I'd strongly suggest eliminating ambiguous terms such as "very small" and the like. I killed quite a few in the copy edit, but you might want to take another look to see if I missed any.
  • I threw a red link in for Maxwellian function. That's something that probably should have an article of its own, based simply from the way you used it. Don't feel as if you need to stub it out, though.
    I changed the link to Maxwell_distribution. Ruslik (talk) 19:22, 21 February 2009 (UTC)[reply]
  • What do red spectra indicate?
    I added an explanation. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • In the sentence "The Trojans' spectra are similar to those of the irregular moons of Jupiter and, to certain extent, comet nuclei, though they are spectrally very different from the redder Kuiper belt objects", what does "they" refer to?
    Replaced "they" with "Trojans". Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • In the sentence "It was triggered by the passage of Jupiter and Saturn through the 1:2 mean motion resonance.", does "it" refer to planetary migration or the capture of the Trojans?
    I changed "it" to "the migration". Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • And as a final question, do these have any connection to Comet Shoemaker-Levy 9? If so, it might be worth mentioning simply because of the well-known nature of that comet.
    There is no connection, as that comet originated in the Kuiper belt, not among Trojans. However added it to See also. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • Thanks for producing an excellent article, and don't hesitate to drop a line on my talk page when you get a chance to read through these. JKBrooks85 (talk) 09:53, 21 February 2009 (UTC)[reply]
  • Thanks for the review, the comments you provided were very useful. Ruslik (talk) 14:54, 21 February 2009 (UTC)[reply]
  • Support but please add a note which explains what happens at L1, L2 and L3 for Jupiter. Is there anything known about them? Nergaal (talk) 18:53, 21 February 2009 (UTC)[reply]
I added a note. Ruslik (talk) 19:18, 21 February 2009 (UTC)[reply]

Ref comments -- Errors found with WP:REFTOOLS.

  • Yoshida2005 | A named reference is used but not defined
  • Nicholson1961 | A named reference is used but not defined
  • Yoshida2005 | A named reference is used but not defined
  • Jewitt2004 | A named reference is used but not defined--TRUCO 22:03, 22 February 2009 (UTC)[reply]
They are actually defined at the end of the article. Ruslik (talk) 13:52, 23 February 2009 (UTC)[reply]
The problem is that the references, like Jewitt2004 is used as <ref name="Jewitt2004"/> but there is no original <ref name="Jewitt2004">(ref content)</ref> reference defined.--TRUCO 22:56, 23 February 2009 (UTC)[reply]
{{Source list}} is used instead. Ruslik (talk) 08:16, 24 February 2009 (UTC)[reply]
Oh. That's something I've never seen before. I guess I'll have to search for that in future FACs. Ref formatting found up to speed.--TRUCO 22:02, 24 February 2009 (UTC)[reply]
  • Support. All of my comments and concerns have been addressed, and I believe this article is comparable to the rest of the solar system FAs. Excellent work by everyone involved. The prose is clear and concise, with only a minimum of necessary technical jargon. Even to me, someone with limited astronomical experience, it's understandable. Great work. JKBrooks85 (talk) 23:57, 22 February 2009 (UTC)[reply]

Image concerns as follows:

  • File:Max Wolf.jpg — I doubt this file is in German public domain, much less US public domain (both required for Commons storage). German copyright is simply 70 years after the author's death, regardless of publication. The image is listed by Britannica to be credited (copyrighted) to Archiv fur Kunst und Geschichte, Berlin. There is no date on when this was taken. However, by noting the similarities of this photo with the one on this page, they should be around the same time (especially when considered to this). The nafa image is listed as taken in Königstuhl, July 1918.(Turns out the date was for the letters, not the image.) If this was taken at the turn of the century and the photographer was 20–30 years old then, he might only have passed away 40 years ago; thus the image is very likely to be still copyrighted in Germany.
    • Just in case, this image cannot be proven to be PD, I suggest this. This 1890 work by Langbein & Cie, Heidelburg, was published on p. 246 of Astronomers of Today and Their Work (1905). Hence, even if it is not German public domain (have to prove both Langbein and Cie were dead 70 years past), it can be stored on Wikipedia (not Commons) as US public domain material (published in US before 1923). Jappalang (talk) 13:36, 24 February 2009 (UTC)[reply]
  • File:AnimatedOrbitOf624Hektor.gif — sources should be provided for the orbital patterns of Jupiter and its satellite.
Awaiting feedback. Jappalang (talk) 13:11, 24 February 2009 (UTC)[reply]
    • You can get the J2000 orbital elements for 624 Hektor from the small-body database: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=624%20Hektor;orb=0;cov=0;log=0;cad=0#elem - which is where I get asteroid/comet/KBO orbital data from (the same data is published in other places though). Jupiter's J2000 orbital elements are from Murray and Dermott's Solar System Dynamics, which was published in 1999 by the Cambridge University Press. Cheers, WilyD 15:23, 24 February 2009 (UTC)[reply]
I've added sources, thanks for the info. I can't upload the alternate Max Wolf picture, though. Serendipodous 20:54, 24 February 2009 (UTC)[reply]
  • All images used in the articles are now verifiably in public domain (US at least). Jappalang (talk) 04:26, 26 February 2009 (UTC)[reply]
  • Support Comment—I performed a PR on this article and all but one of my concerns have been addressed. I gave it another read through just now and I think it deserves FA status. My one issue is regarding the statement about, "this disparity is probably due to observational bias from their respective positions relative to the Milky Way." Intuitively I'd expect the Lagrange points to spend equal amounts of time along the line of sight to the galactic plane, so this leaves me a little perplexed.—RJH (talk) 20:27, 24 February 2009 (UTC)[reply]

This is what the source says:

Given that the best characterized (brightest) Trojans show the smallest deviations of N4/N5 from unity, it is reasonable to suppose that the larger values of this ratio are produced by observational bias in favor of one cloud over the other. Such a bias could result from unequal observational coverage of the L4 and L5 clouds, perhaps due to their placement with respect to the Milky Way, making the detection of faint Trojans more difficult in one cloud than in the other. A careful experiment to determine N4/N5 free of the effects of observational bias has yet to be reported and is urgently needed.

I can't go into any more detail than that. Serendipodous 20:44, 24 February 2009 (UTC)[reply]

Indeed, that is a perplexing statement, but if Jewitt claims as much, it is probably true. The only guess I can make is that the limiting survey(s) were arranged in time such that this is the case (e. g. if the survey that determines the limit was January 23rd 1995 - February 17th, 1995, the backgrounds would definitely be different). WilyD 21:26, 24 February 2009 (UTC)[reply]
A Google search turned up Freistetter (2006) which (to me anyway) appears to indicate there may be more to the discrepancy than observational bias. But I don't have full access to this paper; just the abstract. Thanks.—RJH (talk) 19:12, 25 February 2009 (UTC)[reply]
I removed the statement about Milky Way and replaced with the statement that L4 swarm may be more stable than L5. Ruslik (talk) 14:13, 26 February 2009 (UTC)[reply]
I am not sure this is really the right approach. Jewitt may well be the authority on minor planets these days, ignoring his statement seems like a misstep. WilyD 14:23, 26 February 2009 (UTC)[reply]
Apparently this claim about the Milky Way background originates with Shoemaker '89 (so sayeth Freistetter), Freistetter then claims that this should've been resolveable by now, and Freistetter definitely isn't claiming his answer is correct. He lists 5 different possible causes, three of which he doesn't investigate at all. It seems like a mistake to change this in this way. WilyD 14:26, 26 February 2009 (UTC)[reply]
{de-indent} It sounds like this will require a consensus decision to resolve, but I don't expect the result will effect the article quality. As my concern WRT the FA status was satisfied, I've changed my preference to support. Thank you for putting together another high quality astronomy article!—RJH (talk) 18:13, 26 February 2009 (UTC)[reply]
  • The "See also" section is quite lengthy; are some of those, or can some of them be, worked into the article? SandyGeorgia (Talk) 22:31, 28 February 2009 (UTC)[reply]
  • I don't know what can be done about this, but I can't even see these numbers in the resolution on my computer (which is high):
  • ... from its rotational lightcurve is significantly higher than that of 617 Patroclus—2.480+0.292
    −0.080     g·cm−3.

Can the sentence be recast to avoid all those different dashes, and I can't read the numbers in the plus or minus construct at all. SandyGeorgia (Talk) 22:36, 28 February 2009 (UTC)[reply]

  • Same here (can't see the numbers in the superscript):
  • ... as being less than that of water ice (0.8+0.2
    −0.1     g·cm−3), ...

SandyGeorgia (Talk) 22:37, 28 February 2009 (UTC)[reply]

The only way to do that is to remove the margins of error, which leads to a less exact but more readable figure. Serendipodous 22:43, 28 February 2009 (UTC)[reply]
Perhaps over time you all can find a new way to do that, since it's not legible perhaps somehow remove it from superscript)? SandyGeorgia (Talk) 22:46, 28 February 2009 (UTC)[reply]
The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.
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