Wikipedia:Featured article candidates/Planet Nine/archive2

Planet Nine

 * Nominator(s): Jehochman Talk 02:08, 14 January 2019 (UTC), Agmartin (talk) 16:46, 14 January 2019 (UTC)

This article is about the hypothetical Planet Nine. This is a specific hypothesis about a specific planet with a projected mass, size and orbit. It is not to be confused with Nibiru cataclysm, an imaginary planet that is the subject of pseudoscientic conjecture (and also an FA candidate at this very moment). The Planet Nine article has cleared a thorough review by several colleagues (in archive 1, and at Talk:Planet Nine). Due to the highly technical nature of many of its sources, I emailed Mike Brown (one of the two authors of the hypothesis) and asked him to review the article for factual accuracy and completeness. Because I am not a professional astronomer, I wanted to make sure we didn't misrepresent or omit anything. He replied, "It's quite good! ...what you have here is remarkably complete. Well done!"

The last planet discovered in our solar system was Neptune on 23 September 1846. Unofficial reports from one of the search teams indicate that there's approximately an 80% chance they have photos of Planet Nine from their recent visit to the Subaru Telescope on Mauna Kea. These photos are being processed and analyzed. We expect an announcement, possibly by the end of January. This could be a once in a lifetime discovery. It would be nice if the article was Featured in time for the announcement so that it could appear on the home page during an intense moment of public interest. The actual discovery announcement would not include much additional information, only the location in the sky and distance. It will take about a year to develop detailed information about the orbit. I anticipate that we can quickly update the article to include a discovery announcement without compromising quality; this event should not make the article unstable. Jehochman Talk 02:08, 14 January 2019 (UTC)

I would like to add a comment about the more technical aspects of the article which were often mentioned in previous Feature Article Review, that I did not locate until it was archived. First, many of the technical terms are used because they refer to specific things and often there is not a simpler term available. Since the original review they have been better defined and their use reduced. I think including those terms and some of the more technical details included in the article are useful and necessary because they will aid those readers who do have some familiarity with astronomy that decide to follow the links to the cited articles, which are often much more technical than this article. Agmartin (talk) 16:46, 14 January 2019 (UTC)

Comments by Squeamish Ossifrage
I've moved my two sets of (lengthy!) resolved issues to Talk per the guidelines for such things. Also, the collapse box templates were... not cooperating, so they weren't really doing much good up here. In any case, I think my concerns with SPS issues have been laid to rest. I'm going to do a pass on prose here, hopefully much more briefly!

Lead
 * In the past, references in the lead (except to attribute quotes) were actively discouraged, on the grounds that the lead serves as an abstract to the article and the actual referenced text is included below. I always had mixed opinions about that practice, and evidently it is no longer rigidly enforced at FAC. That said, there are quite a few references that are only cited in the lead, which strikes me as incorrect under the lead-as-summary article model.
 * "proposed planet". Well... yes. Is there a reason we're not calling it a "hypothetical" planet. After all, that's what the linked list uses. I'm not convinced this is wrong as written, just curious about the process.
 * "These eTNOs tend to have their points of closest approach to the Sun clustered in one direction". Is it correct to say that "points" are clustered in a "direction"?


 * I've fixed these three items. There's still one reference that is lede only, but it is a special case.  We need it to say that the planet hasn't been discovered as of 2018.  That's a fact we want to state up front, and it's not really necessary to repeat it later.  Within the next week a new paper will come out that will allow us to clean this up a bit more.  For now, I think it is much better than before. Jehochman Talk 02:45, 9 February 2019 (UTC)

History
 * "conundrum of Uranus's orbit". As I recall, that "conundrum" eventually resolved itself with better measurements? In any case, this introduces a question that isn't ever answered in the article. Perhaps an explanatory footnote here to avoid bulking up this section with a tangential topic?
 * could you get this one? Jehochman Talk 03:19, 9 February 2019 (UTC)
 * This bit still needs work. Actually, the sentence in question in currently not quite grammatical, suggesting that the "conundrum of Uranus's orbit" was "named Planet X". Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)
 * I think it is correct now. Jehochman Talk 08:56, 16 February 2019 (UTC)


 * At a minimum, link Caltech, but consider also using the institution's full name.
 * Done. Jehochman Talk 03:19, 9 February 2019 (UTC)

Hypothesis
 * The History section introduces several different models. There's no section lead to §Hypothesis, so it's not immediately clear to a lay reader which of the previously-mentioned hypotheses is being presented here, or why one of them is being favored. I'm not sure the best way to resolve this. Perhaps consider moving the last paragraph of §History to serve as a section lead here, and renaming this "Current hypothesis" or "Batygin/Brown hypothesis" or something of that nature? To be honest, I'm not sure that's the right choice either. There are potentially due weight issues to consider also.
 * Moved it, renamed sections a bit. Jehochman Talk 03:19, 9 February 2019 (UTC)
 * Much improved in this regard. Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)


 * "In fact, if it once orbited the region of the gas/ice giants..." I'm not sure that "in fact" is the proper way to introduce a sentence based on a hypothetical. Really, you can probably just cut those two words entirely and be fine here.
 * removed Agmartin (talk) 22:47, 8 February 2019 (UTC)


 * I believe the MOS would prefer in situ be italicized (both times).
 * Done. I think there were three. Jehochman Talk 16:42, 9 February 2019 (UTC)


 * "...leaving it with a mass lower, or somewhat lower, than that of Uranus and Neptune." I know what point this is making, but a lay reader is likely to find the "lower or somewhat lower" construction redundant or somewhat redundant.
 * Done. Jehochman Talk 16:42, 9 February 2019 (UTC)


 * " Although the odds of capture can be higher..." This whole sentence is a bit of a garden path. The initial clause poses a question (higher than what), but the answer doesn't come until the very end. I might consider rewording this entirely.
 * I've tried to unscrew this. Jehochman Talk 03:19, 9 February 2019 (UTC)
 * This is much better now. Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)

Evidence
 * Somewhat pedantic question. Is this evidence for Planet Nine, broadly speaking? Or is this evidence for the hypothesis in §Hypothesis?
 * I've clarified it. Jehochman Talk 03:19, 9 February 2019 (UTC)


 * Is it accurate to describe simulations as "evidence"?
 * Yes. Jehochman Talk 03:19, 9 February 2019 (UTC)


 * This section has some really long subsection titles. The first three subsections are especially noticeable (and to some extent, the fourth). Is is possible to shorten these?
 * Done. Jehochman Talk 03:19, 9 February 2019 (UTC)
 * Quite a few subsection titles are still longer than what I'd consider the average for FA articles (or articles in general!), but I don't think they're excessively so. No actionable objection to the current title lengths. Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)


 * The orbits diagram has no caption.
 * DOne. Jehochman Talk 03:19, 9 February 2019 (UTC)


 * You introduce M⊕ here, although you've discussed things in terms of Earth masses previously. Consider moving this to the first appearance so that you can use the short form throughout. Actually, looking further, you really only use that unit symbol in this section. Consider taking a consistent approach.
 * I would move footnote G to immediately following "orbit:", rather than attached to the first entry in the list (as it applies throughout).
 * could you get these last two? Jehochman Talk 03:19, 9 February 2019 (UTC)
 * Agmartin has fixed these both. Jehochman Talk 16:48, 9 February 2019 (UTC)

Reception
 * Again, I'm fairly certain this is reception of only the current (Batygin and Brown) model. Was there any notable responses to the previous models, like the 2012, 2014, or 2015 hypotheses mentioned back in §History. I'm fairly sure at least some of those were ruled out on the basis of further data refinement, but if we've got an RS that addresses it, that would be good if this is going to be a top-level section, rather than part of the Batygin and Brown hypothesis discussion. That said, some of the alternative hypotheses already include reception information. So perhaps the right choice is to bundle an awful lot of this structure into §Hypothesis.
 * DOne. Jehochman Talk 03:19, 9 February 2019 (UTC)

Alternate hypotheses
 * Shouldn't this be alternative?
 * fixed Agmartin (talk) 22:47, 8 February 2019 (UTC)

Naming
 * Is "typically" the right word here? Planet discoveries aren't really typical, after all.
 * I've added clarifying context. Jehochman Talk 03:19, 9 February 2019 (UTC)

Attempts to gather additional evidence
 * Broadly: What makes something belong in this section rather than §Evidence or §Reception?
 * This had been where details from new papers discussing investigations by groups other than Batygin and Brown of the effects of Planet Nine were added. Much of what had been in this section has been incorporated into other parts of the article, for example a bunch of the one sentence summaries in the last paragraph under simulations were discussed as short paragraphs in this section in the past. Some were left here because they are disputed, for example the analysis of resonances. The analysis of Pluto's orbit is included because it was looking for signs of Planet Nine, but may have found something else, or it may just be observational errors. It wouldn't really fit under alternative hypotheses because it doesn't offer an explanation for the orbits of the eTNOs. Some are still here because no one found a good place to move them to. I suppose a couple might fit under observations, I'll think about moving them. Agmartin (talk) 22:23, 10 February 2019 (UTC)
 * I don't think we should have a rubbish bin of random pieces as a section. If this stuff is not important, let's junk it.  If it is important, let's sort it to the correct section, making new ones if we must. Jehochman Talk 02:28, 11 February 2019 (UTC)
 * Done Agmartin (talk) 21:10, 11 February 2019 (UTC)
 * If nothing else, I think this restructuring was the most important prose improvement the article has received. Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)


 * There are some mighty long subsection titles here, too.
 * I've chopped those down. This is actually all attempts to help find the thing rather than observe it.  The idea is to constrain the search space.  I guess that's a reasonably good section title.  Jehochman Talk 03:19, 9 February 2019 (UTC)

My apologies for the long delay between my last source evaluation and this prose read-through. As far as my preferred outcome, this is still just in comment territory. Squeamish Ossifrage (talk) 21:42, 8 February 2019 (UTC)
 * thank you, particularly for your feedback on headings. We’ve made short work of this list, and I think the article has been improved. Jehochman Talk 19:18, 9 February 2019 (UTC)
 * There's one prose issue that still really needs some additional resolution. Also, a second read-through of the source list for formatting problems made me notice that Patel (21 January 2019) is still in sentence case although you've switched other articles to title case. Frankly, it wouldn't hurt to do a quick audit of all of them in case I missed more than this one last time! In any case, I'm probably about out of actionable issues, so this can be deemed a support, conditional on something happening to that "conundrum" sentence. Squeamish Ossifrage (talk) 05:15, 16 February 2019 (UTC)
 * I fixed and checked the references. The conundrum sentence has been completely reworked for clarity. Mush improved. I think we’re all set.  Thank you so much. Jehochman Talk 23:13, 16 February 2019 (UTC)

Support by Jens Lallensack

 * Further surveys are ongoing using NEOWISE and the 8–meter Subaru telescope. – can you link these?
 * done. Agmartin (talk) 18:46, 2 February 2019 (UTC)


 * Following the discovery of Neptune in 1846, there was considerable speculation that another planet might exist beyond its orbit. These theories predicted the existence of a planet, often referred to as Planet X. The Planet Nine hypothesis predicts a specific planet of a certain size and with certain orbital characteristics that are different from past theories. – has no source (possibly resulting from paragraph breakup?)
 * Jehochman took care of this Agmartin (talk) 22:04, 2 February 2019 (UTC)


 * This would increases the inclinations – increase?
 * done Agmartin (talk) 18:46, 2 February 2019 (UTC)


 * Alignment due to the Kozai mechanism – This alternate hypothesis also proposes the present of an unknown planet. It might be helpful to add what the difference between this planet and planet nine would be; why are both hypotheses distinct?
 * would specifying the circular orbit and semimajor axis in the first sentence be sufficient? Agmartin (talk) 18:46, 2 February 2019 (UTC)


 * DES observes about 105 nights per season, lasting from August to February. – source?
 * that appeared to be quoted from the DES wikipedia article, also unsourced, i've updated the number from a recent article since the survey has been completed. Agmartin (talk) 19:54, 2 February 2019 (UTC)


 * WISE satellite – spelled out and linked in the lead, but should be at first mention in the body also.
 * done Agmartin (talk) 18:46, 2 February 2019 (UTC)


 * that in Batygin's opinion, could be covered in – are the commas right? I think either a comma is needed behind "that", or the comma behind "opinion" needs to be removed.
 * rewrote to remove both commas Agmartin (talk) 20:02, 2 February 2019 (UTC)


 * where Cassini data suggest Planet Nine may be located – this Cassini data was not previously mentioned, so should be introduced here.
 * simpler to just say it includes part of the predicted track Agmartin (talk) 19:54, 2 February 2019 (UTC)


 * An analysis of Cassini data on Saturn's orbital residuals – what are orbital residuals?
 * done Agmartin (talk) 20:14, 2 February 2019 (UTC)


 * with boundaries: right ascension 3.0h to 5.5h and declination −1° to 6° – I suggest reformulating to get rid of the colon and have a full sentence for better reading flow.
 * done Agmartin (talk) 20:14, 2 February 2019 (UTC)

--Jens Lallensack (talk) 10:02, 2 February 2019 (UTC)
 * "An undiscovered planet outside the orbit of Neptune, 10 times the mass of Earth, would affect the orbit of Saturn, not Cassini ... This could produce a signature in the measurements of Cassini while in orbit about Saturn if the planet was close enough to the Sun. But we do not see any unexplained signature above the level of the measurement noise in Cassini data taken from 2004 to 2016." – This appears to be two separate quotes rather than a long quote where something is left out (as indicated by the …). I think it might be best to dissolve the first quote (write someting like "X stated that …"), and just keep the second one.
 * I paraphrased this quote Agmartin (talk) 21:05, 2 February 2019 (UTC)


 * Observations of Saturn's orbit neither prove nor disprove that Planet Nine exists. Rather, they suggest that Planet Nine could not be in certain sections of its proposed orbit because its gravity would cause a noticeable effect on Saturn's position, inconsistent with actual observations. – Not sure, but might it be more helpful to the reader to place this more general information at the beginning of the section?
 * moved up to save reader's time since the results discussed are mostly inconclusive Agmartin (talk) 20:36, 2 February 2019 (UTC)


 * An analysis of Pluto's orbit by Matthew J. Holman and Matthew J. Payne – misses the date. Also, both where already mentioned previously, but without the middle initial. You can just write Holman and Payne without first names, as you did for Batygin and Brown in the same sentence.
 * done Agmartin (talk) 19:01, 2 February 2019 (UTC)


 * Konstantin Batygin – Here also, you sometimes give the first name, and sometimes not. Mentioning it at first mention would suffice.
 * removed one mention, the other is part of list of authors with Elizabeth Bailey, whose first name isn't mentioned elsewhere. Agmartin (talk) 18:54, 2 February 2019 (UTC)


 * the commensurabilities (period ratios consistent with pairs of objects in resonance with each other) – explanation is difficult to understand. What periods? Would be orbital periods, right?
 * done Agmartin (talk) 19:01, 2 February 2019 (UTC)


 * Optimal orbit if objects are in strong resonances – The first paragraph of this section is very detailed in comparison with other parts of the article, and difficult to comprehend.
 * I removed the objects from their analysis that were not in resonance, does that make it easier to follow? Agmartin (talk) 21:55, 2 February 2019 (UTC)


 * In an article by Carlos and Raul de la Fuente Marcos – I suggest "In an 2017 article"
 * done Agmartin (talk) 18:54, 2 February 2019 (UTC)


 * This correlation is unlikely to be the result of – why not "this distribution", to connect to the previous sentence?
 * done Agmartin (talk) 19:09, 2 February 2019 (UTC)


 * The value of their spectral slopes suggests that the surfaces of (474640) 2004 VN112 and 2013 RF98 can have pure methane ices (like Pluto), highly processed carbon compounds and some amorphous silicates. – What is the relevance of this info for Planet Nine?
 * not relevant, removed Agmartin (talk) 19:09, 2 February 2019 (UTC)


 * Similarities between the orbits of 2013 RF98 and 2004 VN112 – What are these? eTNOs?
 * done Agmartin (talk) 19:09, 2 February 2019 (UTC)


 * highly processed carbon compounds – what does this mean? Processed by what? Maybe link "processed" to the correct process?
 * not relevant, removed Agmartin (talk) 19:09, 2 February 2019 (UTC)


 * All in all, the article is much better than it was at the previous nomination. I'm close to supporting now, pending above issues. --Jens Lallensack (talk) 11:23, 2 February 2019 (UTC)
 * All done. Agmartin (talk) 22:04, 2 February 2019 (UTC)
 * I've checked them and it seems like we've done our best. please let us know if our fixes are sufficient. Jehochman Talk 00:25, 3 February 2019 (UTC)
 * Thanks. Save one more issue introduced by the recent edits below, I'm happy to support now. --Jens Lallensack (talk) 09:47, 3 February 2019 (UTC)


 * Five objects would be near resonances with Planet Nine if in was in this orbit: and Sedna (3:2) – "nearly in resonance"? remove the "and" before Sedna? --Jens Lallensack (talk) 09:47, 3 February 2019 (UTC)
 * Done. Thank you. Jehochman Talk 12:31, 3 February 2019 (UTC)

Coord note
This has been open almost six weeks and doesn't yet have the level of commentary and support for promotion that I'd hope to see by this stage; we'll also need a spotcheck of sources for accurate use and avoidance of close paraphrasing, and an image check (assuming I haven't missed those) so we still have a way to go. At the same time I'm loathe to archive because the nominators have addressed all outstanding issues and have support from the two reviewers so far. I think it'd be reasonable to request the spotcheck and the image review at the top of WT:FAC and that might also generate some additional broader commentary -- or perhaps Cas might be able to bend his experience of astronomical articles to this one? Cheers, Ian Rose (talk) 11:52, 23 February 2019 (UTC)


 * We had an image review in archive1, and I think the issues were fixed. A new image review should be quick. Jehochman Talk 12:17, 23 February 2019 (UTC)


 * Cas is now supporting and we have resolved any issues noted in JJE's image and sources spotcheck (below). What's the next move? Jehochman Talk 01:33, 28 February 2019 (UTC)
 * I think we're about there now, I'll give it my usual once-over shortly and see if we can't wrap it up. Cheers, Ian Rose (talk) 07:48, 28 February 2019 (UTC)
 * Okay, I've tweaked a few words here and there but a couple of things:
 * The first para of Observations: Orbital clustering of high perihelion objects ends with an uncited statement that I'd expect to be sourced.
 * There are several duplinks in the article, some of which might be justified for an article of this depth and length but pls check and rationalise where you can. This script highlights dups in red.
 * I won't hold up promotion over the duplinks but I'd like to see the unsourced statement dealt with before proceeding. Tks/cheers, Ian Rose (talk) 12:40, 28 February 2019 (UTC)
 * If you mean this "Trujillo and Sheppard's hypothesis about how the objects would be aligned by the Kozai mechanism has been supplanted by further analysis and evidence" the next paragraph goes into specific details. Agmartin (talk) 21:49, 28 February 2019 (UTC)
 * Agmartin added a reference in any case. I did a pass to remove duplicate links a few weeks ago. I will do another pass tonight. Feel free to promote the article whenever you like.  Jehochman Talk 22:32, 28 February 2019 (UTC)


 * Okay, tks for all that. Cheers, Ian Rose (talk) 22:46, 28 February 2019 (UTC)

Comments Support from Cas Liber
(feel free to rejig so coord note section is at bottom) It reads a lot better and looks alot more polished now. Queries below:


 * Should the Alignment due to the Kozai mechanism go in the History section as it antedates the current hypothesis?
 * could you look at this? Jehochman Talk 03:56, 24 February 2019 (UTC)
 * Good question, before the Feature Article Review started the Kozai mechanism was discussed briefly in the first paragraph of Observations (which has since been expanded to to explain the various technical details) with a link to the Alignment due to the Kozai mechanism for those that wanted more detail . It is currently mentioned very briefly in the last paragraph of History, though without reference to the Kozai mechanism. I'm hesitant to push more of it into History (and inclination instability which also preceded Batygin and Brown's hypothesis) as this would add a bunch of technical material ahead of the basic Planet Nine details that most readers would be more interested in. Perhaps a link to the section in History instead would be better? Agmartin (talk) 19:39, 24 February 2019 (UTC)
 * Ah, didn't realise. ok. good as it is Cas Liber (talk · contribs) 20:36, 24 February 2019 (UTC)


 * Maybe a line in the lead on alternate explanations of TNOs? especially as Planet Nine is still only a theory?
 * I’ve added this: . Jehochman Talk 03:56, 24 February 2019 (UTC)


 * I also saw Planets_beyond_Neptune and was wondering why this was not included. I must admit, given both Planet X and Planet Nine are hypotheses, I find their being separated as a little arbitrary but not a strong issue. Actually the last statement of the article explains this well. Wondering whether that should be incorporated in lead.
 * I’m not sure how to fit this into the lede without adding too much detail. We’d have to explain Planet X. Maybe we could add a statement to the History section that Planet Nine is not Planet X. We’ve already got a hat note atop the article.  Thank you, Cas.  Jehochman Talk 03:56, 24 February 2019 (UTC)
 * actually strike that. have had a rethink. The one liner you just added is sufficient. Cas Liber (talk · contribs) 11:27, 24 February 2019 (UTC)

In summary, I am close to supporting on comprehensiveness and prose. Just need to look again and think. It is a tricky subject to encapsulate well. Cas Liber (talk · contribs) 02:38, 24 February 2019 (UTC)

JJE's commentary

 * Images:
 * File:Planet nine artistic plain.png: License and use seem fine for me.
 * File:Planet nine path in orion2.png: One would like to know where the background comes from.
 * Stars? Hipparchus/Tycho2 star databases. I generated with my own program, using original example orbital parameters from Mike Brown. Tom Ruen (talk) 20:55, 24 February 2019 (UTC)
 * File:Planet Nine comparison.jpg: Might be useful to know where the background comes from.
 * I’ve added sources for the Earth and Neptune images. The P9 sphere seems to be original. However, we’re going to need to edit this image when the projected size of P9 is reduced officially. There’s a new paper coming out this week. We know what it’s going to say. Jehochman Talk 02:54, 26 February 2019 (UTC)
 * I removed this image because the latest and greatest scientific paper estimates that P9 is not as large as shown. Jehochman Talk 18:26, 27 February 2019 (UTC)


 * Spot check:
 * 103: I think you may want to give a page number #8; also the source notes that this is apparently an inaccurate way to refer to this phenomenon.
 * Most sources that I have seen refer to it using this term, the note is included for those who may encounter it in one of those. I don't recall seeing any using her term since. Though I think she is pointing out the first name for it, I've added (perhaps erroneously). Agmartin (talk) 20:20, 24 February 2019 (UTC)
 * 106: "Precession" is not mentioned in the source. I also notice that at one point the article says "simulation" and at the other "simulations".
 * added citation that included this bit, rephrased as circulates as that is the word they used, and fixed mismatch. Agmartin (talk) 18:13, 25 February 2019 (UTC)
 * 39: Does not mention "Planet Nine", which the other source mentions however. I don't think these sources speak of Margots opinion, though, so the in-text attribution seems questionable to me.
 * The blue box on the upper right has his name, as does the browser tab, it appears to be one of a number of his personal pages. Agmartin (talk) 17:53, 25 February 2019 (UTC)
 * 125: Seems OK to me.
 * 53: Is it just me, or does this source only explain how Planet Nine relates to comets, without supporting the rest of the paragraphs sourced to them? I am not sure if the other sources fill that gap.
 * The semimajor range and mass of the Planet 9 cloud are discussed on pages 19-20 of arxiv version. Inclination distribution, including perpendicular orbits are shown in Figure 6. Agmartin (talk) 19:57, 24 February 2019 (UTC)
 * 38: See 39.
 * 7: Where is the 20,000 year number supported? Also, there are lower mass estimates in the source.
 * Upcoming paper (next few days?) will include new numbers, this will be better addressed then. Agmartin (talk) 20:20, 24 February 2019 (UTC)
 * 10,0000-20,000 years is mentioned in a couple of the references in the body of the article. (I assume you are referring to the lede, a previous reviewer thought there were too many references there so the one with that number may have been removed) Agmartin (talk) 19:43, 25 February 2019 (UTC)
 * I've removed this number because it's now obsolete. We know the semi-major axis is projected to be 400 - 800 AU.  I could calculate an orbital period based on that range (it's a simple formula), but let's just wait for somebody to publish a number.  Jehochman Talk 15:33, 27 February 2019 (UTC)
 * 15: Seems OK.
 * 102: Seems OK.
 * 76: Seems OK, but what is the source for the next sentence?
 * probably the Oort cloud wikipedia article, I'll check. Agmartin (talk) 19:46, 25 February 2019 (UTC)
 * Yep, that's where it was from. Added a more accessible citation than that article used. Agmartin (talk) 20:14, 25 February 2019 (UTC)
 * 14: Seems OK to me.
 * 71: I am not sure if the source discusses perihelial changes. I general this source is quite dense; I am tempted to AGF on it.
 * It's discussed in section 5.2, though primarily as eccentricity changes. This article on Batygin and Brown's blog was less technical, but was removed during the Feature Article Review because it was a self-published source. Should it be put back in? Agmartin (talk) 20:29, 24 February 2019 (UTC)
 * Are the authors of this self-published source recognized experts in the field? Jo-Jo Eumerus (talk, contributions) 19:58, 25 February 2019 (UTC)
 * Yes. They are astrophysics professors at Caltech. Jehochman Talk 02:37, 26 February 2019 (UTC)
 * Batygin is the author of that blog post and a co-author of the source article. Agmartin (talk) 16:51, 26 February 2019 (UTC)
 * 140: Seems OK to me.
 * 50: Seems OK.
 * 66: To me it sounds like the source says that Planet Nine would increase the number of high-inclination orbits. It also looks like #53 does cover much of the content sourced to this.
 * see 53 Agmartin (talk) 20:06, 24 February 2019 (UTC)
 * taking a second look I'm guessing you are referring to the second time it is cited, figure 3 of 66 shows the inclination distributions as lines with a sizable fraction at inclinations greater than 50 degrees, without Planet Nine these nearly nonexistent. 66 also shows relative sizes of Oort cloud in fig 2. Agmartin (talk) 18:11, 25 February 2019 (UTC)
 * 95: The list of authors in-text is incomplete.
 * Inclination instability was initially proposed by the two authors in the text. Moved that citation up. Agmartin (talk) 20:06, 24 February 2019 (UTC)
 * 58: Seems OK.
 * 127: Seems OK.
 * 125: Redundant?
 * 62: Seems OK.
 * Jo-Jo Eumerus (talk, contributions) 10:30, 24 February 2019 (UTC)
 * I think most of the points have been addressed. Last night a new 92 page paper was published by Batygin, Brown and others.  We've gone through the article and removed some stuff that is now obsolete and updated the projected orbit and mass.  Some further additions will probably happen over the next few days, but for the moment the article is stable, correct and up to date.  Could you let us know which may require further work?  Jehochman Talk 15:33, 27 February 2019 (UTC)
 * I'll have to punt this; real life problems and given that the references are now renumbered it'd be a PITA to recheck them again. I'll AGF that the fixes here have resolved the issues. I note that the This is because objects move more slowly when near their aphelion, in accordance with Kepler's second law. isn't referenced but I am tempted to let it slide as it's restating an uncontested law of nature. Jo-Jo Eumerus (talk, contributions) 16:57, 27 February 2019 (UTC)
 * Ah yes. For whatever it’s worth I checked your points independently of Agmartin and made sure they were resolved.  The Kepler’s Law statement is provided as context to help lay readers. It is not the least bit dubious. Jehochman Talk 18:23, 27 February 2019 (UTC)

Ian Rose (talk) 22:47, 28 February 2019 (UTC)