User talk:Kheider

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I’ve noticed that you’re changing diameters in many TNO articles. If you’re updating the data, please consider the following:

• Always provide the source (published scientific article)
• Do not use Internet sites other than directly related with a recognised astronomical institution (they provide the sources: published papers)
• Avoid changing the values with one sigma error e.g. 800 km ± 50 by a single figure 853. With no error margin the figure is meaningless.
• Finally, if you’re a johnstonarchive fan, use the references from this page: [1] and not unreferenced figures.

Otherwise, a well-meant update actually ruins the work of many editors and will ultimately be reverted as unreferenced. Eurocommuter 06:47, 5 September 2006 (UTC)[reply]

Ceres is not considered as an asteroid and is considered as a Small Solar System Body. -- Deenoe 14 October 2006 (UTC)

There has been NO OFFICIAL STATEMENT from the IAU committee removing (1) Ceres as an asteroid. A poorly worded Q&A article that says Ceres both 'IS and WAS' is NOT a good official statement.

Using the IAU 2006 definitions an object is either a Planet, 'Dwarf Planet' (compound noun), or a Small Solar System Body (SSSB). This does not affect the definition of the older terms asteroids and comets.

Pluto is a Kuiper Belt Object (KBO) even though it is also a 'dwarf planet'. I believe that 1 Ceres will still considered an Asteroid since it orbits in the asteroid belt and has the same origin as the other asteroids. In the closing sentence, MPEC 2006-R19 states, "does not preclude their having dual designations"

Has Pallas become the 1st asteroid discovered? Has Vesta become the largest asteroid (at least until the IAU decides that since Vesta is a damaged, differentiated protoplanet that it was probably a healthy dwarf planet in the past)? *IF* Ceres is truly no longer an asteroid, because it is spherical, then those two very basic questions have new answers.

2 Pallas is similar to 4 Vesta in volume, but significantly less massive. If the IAU ever reclassifies Vesta as a dwarf planet AND officially declares that dwarf planets are not asteroids, then Pallas may someday be considered the largest asteroid. -- Kheider 23:33, 17 October 2006 (UTC)[reply]

Please do not edit other comments, unless merely formatting a conversation to become more readable (e.g. by inserting proper indentations). Otherwise, such edits are unnecessary and could be considered to corrupting the original context. Thank you. --Iamunknown 18:43, 18 October 2006 (UTC)[reply]

Under "Spheroid or not?", I added a link to Neptune's moon Proteus. Proteus is one of the largest non-spheroids in the solar system. Your re-edit (rv) moved the link from the moon to Greek mythology ;-) Kheider 19:01, 18 October 2006 (UTC)[reply]

You removed the link again. Please consider, if doing anything, disambiguating the link. There is an article about the Neptunian moon Proteus (moon). You could have replaced [[Proteus]] with [[Proteus (moon)|Proteus]]. I am restoring the link with the pipe-link disambiguation Proteus (moon). --Iamunknown 16:58, 19 October 2006 (UTC)[reply]

Since I have only been using Wiki for 1 month, I did not known how to get Wiki to link to the wiki copy of the "(moon) Proteus". The original link to Greek mythology would not help anyone trying to study spheroids. Thank you for making Proteus point to something relevant to the discussion. Kheider 18:21, 19 October 2006 (UTC)[reply]

I didn't realize that you are relatively new here. Please let me formally welcome you to Wikipedia! Here are some pages that you might find helpful:

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An occulation chord is the width of an asteroid along a particular line, as inferred from stellar occulation. This is not the same as a solar eclipse: no asteroid can be observed to transit the Sun (particularly since most are further from the Sun than the Earth). The process works like this: we can predict roughly where an asteroid will pass in front a star, as seen from some part of the surface of the Earth. We then place a large number of telescopes across this region, with known positions, and measure the brightness of the star + the asteroid as a function of time. We see a drop when the asteroid passes in front of the star, and a jump when the star becomes visible again. The time of these events tells us the extent of the asteroid along a line defined by its projected velocity, a single chord. Taking many telescopes, we can construct an occulation silhouette. This process is very laborous and prone to difficulty, but was the only way to get asteroid dimensions with any accuracy until the advent of radar astronomy, adaptive optics, and spacecraft observations.

So an occulation chord passing through the equator of the asteroid is equal to the diameter of the asteroid? Does it matter that the Earth is only passing through the penumbra? Kheider 20:04, 20 October 2006 (UTC)[reply]

There is no penumbra in an asteroid occulation, because the asteroid's angular size is far larger than the angular size of the star (an asteroid may subtend an angle of a tenth of an arcsecond, while stars have angular sizes in the milliarcsecond range). The penumbra in a solar or lunar eclipse is caused by diffraction (which is neglible for an object with no atmosphere) and by partial shadowing, which doesn't apply here. An occulation chord passing through the equator is not the same as the diameter, because the diameter of an irregular asteroid is ill-defined. The occulation chords given the plane-of-sky silhouette, and nothing else. Michaelbusch 22:14, 20 October 2006 (UTC)[reply]

When linking an image, template, or category without adding it to the article, use a leading : For example: [[:Category:Binary_asteroids|Category:Binary_asteroids]] Rmhermen 16:24, 28 October 2006 (UTC)[reply]

When a KBO's spectral class is called '(moderately red)' what does that mean? Does that mean it does not reflect well in the visible light but reflects better in the infrared? Or does it mean that object is reddish in color? 50000 Quaoar, 20000 Varuna, and 28978 Ixion are all listed as such. 38628 Huya says, "appears to be dark red, suggesting it is covered with ancient organic chemistry." Thanks -- Kheider 01:42, 2 November 2006 (UTC)[reply]

'Red' in this context means that the object is relatively more reflective in the red and near-infrared than in the blue (the reflectance spectrum slopes upward toward red). Such spectra on outer solar system objects are often caused by organic compounds, such as tholins. However, to the unaided eye these objects would be brownish or black, because of their low albedos. Michaelbusch 01:49, 2 November 2006 (UTC)[reply]

So on the plot TNO Colors I assume that both 1994 ES2 and (119070) 2001 KP77 would be red? -- Kheider 23:15, 2 November 2006

Yes. Redder objects have higher V-R and B-V. On this plot, (0,0) is equal magnitude in all three bands. This is not quite the same as a perfectly white, because the bands are broad, but a white object would be at (0,0). A blue object would plot at negative B-V and negative V-R. Michaelbusch 23:19, 2 November 2006 (UTC)[reply]

So would 1994 ES2 be redder than (119070) 2001 KP77? -- Kheider 23:48, 2 November 2006 (UTC)[reply]

Not necessarily. 1994 ES2 has higher V-R, but much lower B-V. This means that ES2 has relatively more blue in its spectrum as compared to KP77. So if we looked only between V & R, ES2 would be more red, but if we looked only between B & V, KP77 would be redder. This simply is a problem with the definition of redness. Michaelbusch 23:56, 2 November 2006 (UTC)[reply]

Hi Kheider, I wonder if we could compare our methods of obtaining the range of magnitudes. While entering angular size values for the planets in their infoboxes, I noticed that the reference I was using (e.g. this one for Saturn) also gave peak magnitudes. The values I obtain based on this (how , I will explain below) differ somewhat from the ranges you put in a few days ago. It'd be good to sort these numbers out.

So, for example, for Saturn, that nasa fact sheet gives:

Apparent diameter from Earth        Maximum (seconds of arc)   20.1        Minimum (seconds of arc)   14.5 Maximum apparent visual magnitude             0.43      

Obviously the maximum magnitude I use is right there. To get the minimum, I assume that the brightness maximum must occur at the same time as the given maximum apparent diameter, and that the minimum brightness must occur simultaneously with the minimum apparent diameter. (This is inapplicable to Venus and Mercury, since they are not in full phase at their closest approach to Earth). This consideration gives a minimum intensity that is (14.5/20.1)^2=0.520 times the maximum, assuming a circular orbit for Saturn, therefore a magnitude change of 0.709, hence a minimum magnitude of 0.43+0.71=1.14. I notice that you obtained a significantly darker minimum magnitude of 1.4, and am wondering at how that comes about. Deuar 15:18, 12 October 2007 (UTC)[reply]

Hi Deuar. I used "A Field Guide to the Stars and Planets" (Pasachoff, 1983) for some of the values, and I used JPL Horizons to confirm the values.

You are right there is deviation based on the source and probably the methods used. I do agree that maximum apparent diameter is important, but keep in mind that the "Sun-Target-Observer angle" (target's apparent PHASE ANGLE as seen at observer's location) might affect magnitude. Some of NASA's own sources conflict one another. :-)

NASA Reference Publication 1349 lists Mercury as high as -2.3 (full phase) on May 19 2006. I went with -1.9
Different sources list values of -4.7 and -4.6 for Venus.
I have confirmed Mars (using Horizons) at -2.88 on 2003-Aug-29: You will need to set the "Target Body" as MB:Mars, the date range to cover 2003, and include the QUANTITIES: 9 (vmag) and 20 (range AU).
I can not get Jupiter's brightest magnitude greater than Mars's maximum in our lifetime.
I have heard (can not remember the source it was years ago), that when tilted at their maximum of 27 degrees, such as in 1988, that the rings increase Saturn's brightness by 0.2 to .7(?) magnitude. The book "A Field Guide to the Stars and Planets", does list Saturn at +0.2 opposition magnitude for 1985 through 1989. In 1984 with the rings only tilted 20 degrees Saturn is listed at +0.3. NASA Reference Publication 1349 lists Saturn at -0.2 (yes, that is a minus) on Jan 2 2004! The +1.47 (Horizons) value for Saturn on 2017-Oct-23 probably does not account for the rings either.

Numbers I used (vs generated with Horizons)
Mercury -1.9 2051-Jun-04 -2.20 (brightest when full)
Venus -4.6 1989-Dec-18 -4.57 (brightest when cresent)
Mars -2.9 2003-Aug-29 -2.88; 2021-Jul-11 1.84
Jupiter -2.8 2010-Sep-20 -2.79
Saturn -0.24 1973-Dec-23 0.42; 2017-Oct-23 1.47 (error since rings tilted a lot!?) (File:Saturnoppositions.jpg)
Uranus 5.5 2048-Feb-25 5.31; 2008-Feb-26 5.95
Neptune 7.7 2032-Oct-07 7.80; 1973-Dec-04 8.02
Kheider 19:28, 12 October 2007 (UTC)[reply]

Yep, it's complicated. Albedo can vary with phase angle and orbital location (e.g. Pluto, Mars, Uranus?) as well. However, i would suppose that the phase angle wouldn't affect the min/max values for the planets external to Earth, since both cases should occur when we view the full face at opposition, or just next to the Sun. This might be a different matter for inclined objects like Pluto or asteroids, though. There's also a matter of which face we're viewing, or the rings of Saturn. Those rings could account for the discrepancy at the minimum magnitude we see if the maximum value given in my fact sheet took them into account (as was probably the case). Pity the fact sheets I know don't explain how the values were obtained! Anyway, I see that you've gone into lots of detail in your investigation, so I'm happy to trust your judgment :) Incidentally, how did you get Horizons to give you magnitudes? I briefly tried looking for a magnitude-related field there, but couldn't find it. Deuar 22:05, 12 October 2007 (UTC)[reply]

Go to Horizons. Make sure it is set to Ephemeris: OBSERVER. Go to "Table Settings" (2nd from the bottom) and click on the blue "change". Make sure that "9. Vis mag. & Surf Brt" has a check mark next to it.  :-) Kheider 22:37, 12 October 2007 (UTC)[reply]

Thanks, I see I was using the wrong Ephemeris type (elements). So, comparing the Horizons magnitude to that given in your new reference, there is a 0.3 difference in brightness (dimmer in Horizons), which is presumably due to the rings. In Horizons they mention that they don't take into account the illumination angle of the rings, but this is ambiguous - are the rings taken into account or not overall? what about viewing angle? etc. It looks like a mess, and any own calculations are bound to be bordering on original research due to the complexity of the thing. :( Well found reference, then! :) Deuar 13:20, 13 October 2007 (UTC)[reply]

It does not appear as if Horizons or the NASA Fact Sheet consider Saturn's ring system. I have updated Saturn to magnitude -0.24 for the 2000-12-08 opposition at ring tilt 24° / solar phase angle 0.038. I wonder how bright Saturn was at opposition in 2002-12-17 when it was at ring tilt 26.5° / solar phase angle 0.027? This abstract does not seem to publicly show it.
-- Kheider 23:59, 14 October 2007 (UTC)[reply]

• Saturn Calculate: ring tilt, diagram with rings, Moons of Saturn
• Moons of Jupiter
• USNO Astronomical Applications / Moon phase dates
• JPL Solar System Simulator

If you can reasonably prove that the data sources are reliable and accurate, you should just go ahead and make the changes. —Viriditas | Talk 04:59, 24 December 2007 (UTC)[reply]

On 27 December, 2007, Did you know? was updated with a fact from the article 2007 WD5, which you created or substantially expanded. If you know of another interesting fact from a recently created article, then please suggest it on the Did you know? talk page.

--Maxim_(talk) 14:40, 27 December 2007 (UTC)[reply]

Could you take a look at this edit - the reference is broken. --mikeu (talk) 19:24, 27 January 2008 (UTC)[reply]

Thank you for the heads-up. I moved the "Horizons1223" citation details to top ref to prevent the ref error that did not exist on 21:35, 3 January 2008. Perhaps citation details should not be placed in external link sections. -- Kheider (talk) 20:14, 27 January 2008 (UTC)[reply]

It might or might not be unlikely, who knows if the astronomical community wants to enlist another planet? I know I'm for it. Besides, Mercury's probably tired of being the littlest! Secondly, size isn't -currently- use to decide which objects get to be "Planets". Thirdly, Eris doesn't cross Sedna's orbit, check the latest version of Celestia if you don't believe me.

• http://www.shatters.net/celestia/ -- IdLoveOne (talk) 21:24, 16 February 2008 (UTC)[reply]

Mass (which is Volume*Density aka size) is used to determine if an object can be orbitally dominant. And a lot of the above statements do not comply with NPOV policies. -- Kheider (talk) 22:51, 16 February 2008 (UTC)[reply]

They don't. I admitted it, but neither is your insistence that Sedna can't be a planet. And as I'd type before, there's only three standards by which a 'planet' is a 'planet,' and "orbital dominance" (except in the case of planets with moons) is not one of them, especially if we're talking about unknown Solar System bodies. You can type until you have carpal-tunnel, but the rules won't be changing until next year. -- IdLoveOne (talk) 02:10, 17 February 2008 (UTC)[reply]

I suggest you read Steve Soter's article at http://arxiv.org/abs/astro-ph/0608359v6 This is what a lot of people suggest going by. Clearing the neighborhood requires orbital dominance. Moons do not effect orbital dominance since they are submissive to a Planet by definition. -- Kheider (talk) 13:06, 17 February 2008 (UTC)[reply]

There are no "cleared neighborhoods," every solar system body from Mercury and beyond has something that imposes on it's orbit. What about the centaur Chariklo, it's all alone in it's orbit & probably just out of the reaches of Saturn and Uranus. If it's found to have hydrostic equilibrium, I say it's fair game for planet status. http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Chariklo;orb=1;view=Far -- IdLoveOne (talk) 00:27, 21 February 2008 (UTC)[reply]

Chariklo will probably look a lot like Phoebe or Hyperion. There are many known Centaurs and their orbit are unstable over a million years as they are perturbed by the dominant gas giants. Some of these centaurs will become future comets. -- Kheider (talk) 01:42, 21 February 2008 (UTC)[reply]

		The E=mc² Barnstar
		For helping get Neptune to FA, and for coining the phrase "a lot of inbred rocks", to which I chortled heartily, I award you the science barnstar. :-) Serendipodous 12:46, 14 March 2008 (UTC)[reply]

Hey mate, about your change to go to the abstract. I understand citing the abstract as it is na HTML and not PDF, but can I still cite the pages where that info appears, even if citing the abstract? Samuel Sol (talk) 15:17, 17 March 2008 (UTC)[reply]

And sorry to hear about your loss. :-( I know how difficult these times can be, and wish you all the best. Serendi^podous 07:12, 3 April 2008 (UTC)[reply]

Thanks :) Though my knees are OK now; mainly it's my ribs that are killing me... Serendi^podous 18:29, 20 April 2008 (UTC)[reply]

You wrote that 1995 GJ is cubewano. But on Minor Planet Ephemeris Service you can find that the object was observed only on two days 1995 Apr. 3-4, and eccentricity is assumed. So, it may be SDO as well as cubewano. Excuse my English. Regards, Chesnok (talk) 08:38, 22 May 2008 (UTC)[reply]

That was one of the first articles that I wrote. I just updated it some. I know that the JPL Small-Body Database Browser lists it as a Cubewano. But I am not sure how official that is given that it was only observed over two nights and is considered lost. Should we use that as the reference? -- Kheider (talk) 16:25, 22 May 2008 (UTC)[reply]

FYI. Thanks again for all of your help on this project. UltraExactZZ ^Claims ~ Evidence 02:10, 7 June 2008 (UTC)[reply]

I'm on the verge of starting an edit war, and having just got blocked for edit warring I really don't want to start over again. I could use a third person arbitration before things get hairy. The issue is quite simple, but rather fraught. There's an article called "Hypothetical trans-Neptunian planets" that was created as a merge article for the articles on the ninth planet and the tenth planet. I've never been a fan of this article; it's meandering, vague, gossipy, unsourced and lacking in anything approaching historical and scientific rigour. Since much of what it said was already in the Planet X article, which is far better sourced and organised, and since no one had made any substantial edits to the other article in months, I decided to merge the other article with Planet X, assuming no one would even notice, let alone care. However, a few days later, to my absolute shock, someone showed up who apparently cared. User:The Tom not only reinstated the other article, but began removing similar material from "Planet X", much to my chagrin, as the material in Planet X was cited and the equivalent material in the other article was not. Eventually we came to a kind of compromise (although not one I liked very much) that "Planet X" would be strictly about Lowell's idea, with all other hypothetical trans-Neptunian planets kept in the other article. Specifically, the other article was to hold material on the recent announcement by Patryk Lykawka of Kobe University that gravitational effects suggest the presence of a large planet in the outer Solar System. Since this is essentially the same rationale for Lowell's Planet X, Lykawka's planet is called "Planet X" in the media. There are also other "Planet X"s out there, proposed by other astronomers.

Nonetheless, I held for a few days, because I didn't particularly care. However, today, a slew of information has been added to the Planet X article about Lykawka's planet, and I realised that if I was to hold to Tom's separation policy I would be spending the rest of my Wiki career removing this information, which I didn't particularly want to do, especially since I felt it should be there anyway, and that the other article wasn't worth saving. So I reverted the merge and reinstated all the old material. But I figured Tom would burst his gasket when he found out, so I thought I'd ask for a second opinion. Let me know what you think. Serendi^podous 14:46, 20 June 2008 (UTC)[reply]

What you mean as summary by mars and gas giant may be rip by white dwarf star? I thoguht Venus and Earth may or may not survive over sun's giant star stage. I thought Venus has slightly less than to survive than Earth. mars is likely to survive, but not positively.--Freewayguy ^{Msg USC} 03:37, 27 June 2008 (UTC)[reply]

Can you please answer this question?--Freewayguy ^{Msg USC} 04:39, 27 June 2008 (UTC)[reply]

Sorry it took me a little time to check sources with Google. See On the Final Destiny of the Earth and the Solar System (Rybicki & Denis 2001). It does appear as if the popular view is that Mercury is almost certainly a goner unless some other process alters its orbit. Venus is "most likely" to be destroyed. Earth is likely to be destroyed, but is more of a coin flip given the limited knowledge we have. So if the Sun engulfs Mercury, Venus, and Earth, Mars will likely be the closest planet to the (white dwarf) Sun. Then over trillions of years passing stars will slowly strip the gas giant planets from the weakened Sun. So perhaps Mars will be the last planet standing. But obviously this is not definitive. -- Kheider (talk) 05:51, 27 June 2008 (UTC)[reply]

Do you think you could give this a once-over to tidy up the prose? I would, but I find it very difficult to edit my own work. Serendi^podous 06:11, 15 July 2008 (UTC)[reply]

Hi Kheider!

Yeah, Serendipodous and I have been discussing the whole 1999 TD10 issue and trying to figure out where to come down. I have quite literally found contradicting sources: some say centaur, some say SDO... so perhaps the best thing would be to remove it for now, but actively pursue this question on the talk page. I'll remove it... Ling.Nut ^(WP:3IAR) 04:24, 18 July 2008 (UTC)[reply]

• I like what you said in your edit summary. Would you please copy that edit summary to Talk:Scattered disc as a comment, so that it will be much more accessible? Ling.Nut ^(WP:3IAR) 04:43, 18 July 2008 (UTC)[reply]

• Did you see Talk:Detached object (astronomy)/GA1? I'm no gonna be able to work on it, but I'm hoping others will. See ya round!! Ling.Nut ^(WP:3IAR) 05:30, 27 July 2008 (UTC)[reply]

Kheider, is there any actual proof that all of the centaurs will be removed from their orbit? Because, especially in the case of Chariklo which doesn't cross any "planet's" orbit, I don't think the article should say that -- especially without citations. As I said in my edit summary, it seems too intangible and unlikely that they all will or that it could be proven that they all will.

In fact, I think I read somewhere that the centaurs between Saturn and Uranus (Chariklo) could survive there for the "lifespan of the Solar System" or words to that effect. --IdLoveOne (talk) 01:42, 28 August 2008 (UTC)[reply]

I added a reference to Jewitt2006 that shows that Centaurs have "short dynamical lives". So, yes all Centaurs will have their orbits rapidly changed. A few of the lucky ones will achieve an orbital resonance that can last for a 3 Myr integration. I do not recall reading a statement that any centaur has an orbit that is stable over the life time of the solar system. -- Kheider (talk) 14:56, 28 August 2008 (UTC)[reply]

Is Chariklo one of the ones that have a long-lasting orbital semi-permanence? What about the asteroids? Will they be thrown from the Solar System or are they permanent? --IdLoveOne (talk) 22:52, 31 August 2008 (UTC)[reply]

According to Horner2004, Chariklo is estimated to have a long orbital half-life of about 10.3 Myr. The typical Centaur has a mean orbital half life of about 2.7 Myr. Remember that Centaurs are Kuiper belt objects that have been scattered so that they flirt with the dominant giant planets. The main belt asteroids are on low eccentricity orbits that do not flirt with major planets. -- Kheider (talk) 05:04, 2 September 2008 (UTC)[reply]

That page confuses me. How could both Makemake and Eris be in the same resonance? Eris is three times farther from the Sun! Serendi^podous 14:15, 11 September 2008 (UTC)[reply]

Gravity Simulator shows Eris in a 17:5 resonance with Neptune and Makemake (2005 FY9) in an 11:6 resonance with Neptune. Having said that I have never used the program so maybe they are merely in a near resonance with Neptune. I am wondering if DES is showing Eris not keeping (removed?) a 17:5 resonance with Neptune over a 10 Myr integration.
-- Kheider (talk) 14:44, 11 September 2008 (UTC)[reply]

If this is true, it should be mentioned in their articles, not in the external links, but I would prefer some more scholarly refs be employed to ascertain it. Serendi^podous 15:12, 11 September 2008 (UTC)[reply]

Until we have more than "the appearance of a resonance", I kind of prefer the links in the external links. Otherwise we have to carefully word it is a possible resonance. I suspect that they will need several more years of observations to confirm these resonances exist. Makemake has an orbit quality of 2 and Eris has an orbit quality of 3.
-- Kheider (talk) 20:04, 11 September 2008 (UTC)[reply]

The Gravity Simulator web pages is using old data for both Makemake and Eris. What appeared to be mean-motion resonances with the data released shortly after discovery, turned out to be simply near-resonances. I'm the author of that web page. I'll update it soon to reflect the current data. I found this discussion from my web logs. —Preceding unsigned comment added by 71.131.186.100 (talk) 05:53, 15 September 2008 (UTC)[reply]

You changed the diameter estimate in the article from "1300-1800" (my edit) to "1200-1600". It seems the source we both used (Brown 2007) is self-contradicting: in the section on Sedna it gives the lower estimate, in Table 1 at the end it gives the higher one. Maybe we should find a better reference. --Roentgenium111 (talk) 16:02, 26 September 2008 (UTC)[reply]

The Spitzer Space Telescope shows Sedna to be <1600km. Browns lower albedo estimate of 0.16 (with H=1.6) also suggests a maximum size of about 1590km. The 1800km maximum seems to be becoming an obsolete figure. -- Kheider (talk) 17:15, 26 September 2008 (UTC)[reply]

Actually, if you go to the wikipedia article, it mentions that the mean radius is 256 km. Do you think this is true? Either way I would be wrong, but 130 km is definitely nowhere near 256 km. Please answer - Interchange88 —Preceding undated comment was added at 20:54, 26 September 2008 (UTC).[reply]

In the article "10199 Chariklo" Reference 1: "Spitzer Space Telescope (2007)" (Table 4: "Adopted Physical Properties") shows a diameter of ~258.6. Where are you seeing the radius listed as 256km? See also Talk:10199 Chariklo. -- Kheider (talk) 21:57, 26 September 2008 (UTC)[reply]

If you check the edit history of the article, you wil see that the mean radius has been changed/revised a few times. I will upload a more up-to-date comparison soon. Thanks for pointing that out - --Interchange88 (talk) 17:21, 6 October 2008 (UTC)[reply]

K, I'm not so sure that ref you provided would stand up to GA scrutiny. It's certainly not a published source, and borders on original research. Serendi^podous 18:15, 29 September 2008 (UTC)[reply]

I would think Mike Brown on his own blog would be a reliable source. -- Kheider (talk) 20:33, 29 September 2008 (UTC)[reply]

Well yeah, but this kinda borders on using a personal email as a source. I dunno. We'll need to see what the reviewer thinks. Serendi^podous 14:45, 2 October 2008 (UTC)[reply]

BTW: Great edit on the classification section. :=) Serendi^podous 16:04, 2 October 2008 (UTC)[reply]

Hello, as part of Wikipedia:WikiProject Good articles/Project quality task force, I have conducted a Good Article reassessment of 3 Juno, to which you have been a major contributor. I have a few concerns that should be addressed if the article is to remain listed as a GA. If you are able to help out, the reassessment can be found here. Thanks, GaryColemanFan (talk) 15:43, 29 October 2008 (UTC)[reply]

Hello, as part of Wikipedia:WikiProject Good articles/Project quality task force, I have conducted a Good Article reassessment of 4 Vesta, to which you have been a major contributor. I have a few concerns that should be addressed if the article is to remain listed as a GA. If you are able to help out, the reassessment can be found here. Thanks, GaryColemanFan (talk) 18:38, 5 November 2008 (UTC)[reply]

Once List of planetary bodies or whatever we finally decide to call it is fully referenced (a long, slow and suicidally boring task) I intend to bring it up for featured list review. The Solar System FT reviewers have demanded that more lists be included, so I've begun a serious drive to get more lists up to FL status. One tack I'm considering following is to merge list of Solar System objects by mass, list of solar system objects by radius and list of solar system objects by surface gravity into a single, sortable list. Do you think there are enough good sources to track down the mass and radius of all the objects? Serendi^podous 13:10, 13 November 2008 (UTC)[reply]

I have been trying to give this some thought. There appears to be difficulty in figuring out the diameter (within a factor of about 2) for typical objects beyond Saturn. For example 2060 Chiron was estimated as 208km in diameter by Campins in 1994, 142km in diameter by spectroscopic observations in 2003, and 230km in diameter by Spitzer in 2007. Since it is not a binary object, we have no idea what it's mass/density is. So for non-binary TNOs I have some confidence in the diameters, but no real confidence in the "unreferenced wiki-assumed" masses/densities.

For the main belt, since it is so much closer and been studied longer, the diameters are known fairly well. But even the mass of 2 Pallas has recently varied from 3.1×10²⁰ (Hilton1999) to 2.3×10²⁰ (Goffin2001) to 2.1×10²⁰ (Baer/Chesley2008). The mass calculations of Pallas and Ceres are interconnected, as the mass of one goes up, the mass of the other will go down. Mass estimates of 4 Vesta have been consistent

52 Europa (300km) was considered the sixth most massive asteroid at 5.2×10²⁰ kg (Michalak2001), but (Baer/Chesley2008) seem to believe it is highly porous at 1.9×10¹⁹ and may have suffered a severe collision. Even 9 Metis (a 190km asteroid that may be the core remnant of a disrupted large asteroid) may be more massive. A lot of asteroids are just starting to get their first mass estimates. -- Kheider (talk) 19:09, 16 November 2008 (UTC)[reply]

How many of these do you think knowing the masses of Vesta and Ceres (and if we're really lucky and get a Dawn flyby, Pallas) will enable us to actually measure, even if crudely? kwami (talk) 09:09, 17 November 2008 (UTC)[reply]

Unfortunately it will probably only reduce the error bar on the calculations. But since the mass of other asteroids are often based (directly or indirectly) on these large perturbers, it will help. Actually going to Ceres will greatly reduce the error bar on Pallas since Ceres and Pallas are one anothers greatest perturbers. -- Kheider (talk) 14:53, 17 November 2008 (UTC)[reply]

Hey Kheider,

You recently updated the estimated mass of 28978 Ixion. Could you also update and ref the diameter?

Thanks, kwami (talk) 09:07, 17 November 2008 (UTC)[reply]

Done. Though keep in mind almost all TNOs assume a large body density of 2.0 g/cm³. One could easily make an argument that we should be using a density "guess" of 1.5 or even 1.3, but at least it puts the generic non-binary TNOs on a level playing field. -- Kheider (talk) 15:03, 17 November 2008 (UTC)[reply]

Just a quick reminder that this article is undergoing a GA reassessment as part of the GA sweeps. It has been on hold for over two weeks, but several concerns remain. If they are not addressed soon, I will have to delist the article. Because it is part of the Main asteroid belt Featured Topic, this would also mean that the Featured Topic would be delisted. There's not much left to do, so any help you can provide would be great. The reassessment page is here. Thanks, GaryColemanFan (talk) 22:45, 20 November 2008 (UTC)[reply]

It might be simpler just to make the list sortable, and then sort it. Also, I think radius and surface gravity can also be included. I'll help you with it if you want to do it. Serendi^podous 18:53, 29 November 2008 (UTC)[reply]

So far I am just trying to get the mass list in the correct order for the asteroids through about 65 Cybele, given 2008 knowledge. I am editing the main articles. Per our above Featured lists talk, I think it would be good to start working on such a sortable list for radius and mass. I doubt the surface gravity has been re-calculcated in the infobox of many asteroids since the old 2005-2006 estimates. I know that I seldom bother to re-calculate the gravity myself when I know the mass is just an educated guess. Could we create an automatic process to take the radius and mass and spit out the surface gravity/escape velocity? -- Kheider (talk) 21:12, 29 November 2008 (UTC)[reply]

I used the work of Karkoschka of 2001 (Karkoschka, Erich (2001). "Voyager's Eleventh Discovery of a Satellite of Uranus and Photometry and the First Size Measurements of Nine Satellites". Icarus. 151: 69–77. doi:10.1006/icar.2001.6597.). He reproceessed old Voayger 2 images and arrived at larger values for sizes. I think NASA/JPL still use older date from Thomas, 1988 (or Davies, 1992). I think Karkoschka's estimates are better. Ruslik (talk) 06:37, 12 December 2008 (UTC)[reply]

Well I checked Karkoschka of 2001 and it appears you are right. In the table V of Karkoschka the values of ${\displaystyle {\sqrt {ab}}}$ are listed (a and b are are major and minor semi-axis of the moon's prolate ellipsoid). However true average radius is ${\displaystyle (ab^{2})^{1/3}}$. I probably uncritically used that strange value.

If you want to read this paper I uploaded it to filefactory (see http://www.filefactory.com/file/4ba0e6/n/Icarus_Karkoschka_2001c_pdf ) Ruslik (talk) 08:15, 12 December 2008 (UTC)[reply]

You must find a better way to include that information. Right now it looks like vandalism. Serendi^podous 00:51, 19 December 2008 (UTC)[reply]

I subbed a planet infobox for the comet infobox, which allowed me to include the physical characteristics. Unfortunately, it also forced me to buch the dates for the last and next perihelia into one line. Serendi^podous 01:00, 19 December 2008 (UTC)[reply]

Thanks for your help. Sorry I got mad. Serendi^podous 03:56, 20 December 2008 (UTC)[reply]

Hey, just wondering, have you completed your mission as per List of Solar System objects by size? I've been thinking of submitting it for peer review to see how much farther we could go with it. Serendi^podous 18:06, 22 December 2008 (UTC)[reply]

No, not yet. I still have some more work to do. I have been trying to decide how to improve the key. I know a lot more will need to be done even after that, but at least it will be a step in the right direction for sourcing the accuracy of the numbers. I have also been in contact with JPLSSD (Last Updated: 2008-Dec-20) and they have finally updated their sizes and albedos for the Uranian irregulars per Sheppard2005. :-) -- Kheider (talk) 19:03, 22 December 2008 (UTC)[reply]

I've been thinking; what if we dumped the lower list and just focused on creating an absolutely comprehensive list of objects above 100 km in radius? Serendi^podous 20:22, 24 December 2008 (UTC)[reply]

I think people will still want to see smaller well known objects on the list. I don't think including the 2nd list harms the main list. Though it may be better to only include objects with known sizes and decent estimates on the mass for the lower list. Still brainstorming... -- Kheider (talk) 21:58, 24 December 2008 (UTC)[reply]

How goes your plan for the page? Are you finished? Serendi^podous 16:28, 17 January 2009 (UTC)[reply]

I will do some edits to it tomorrow. But my brainstorming has not come up with any magical fixes. -- Kheider (talk) 04:41, 19 January 2009 (UTC)[reply]

I want to expand the "radius only" objects in the 100km+ table to include mass and volume, assuming sphericity and Pluto's density. I was wondering if you thought that was a good idea. Serendi^podous 13:40, 19 January 2009 (UTC)[reply]

I will start adding the "^R Radius has been determined by various methods, such as optical (Hubble), thermal (Spitzer), or direct imaging via spacecraft" objects. Since these are the only objects with decent diameters, though still unknown densities/masses. But I do feel that inserting generic values for the unknown diameters (assumed albedos of 0.09 objects), with unknown masses might be counter productive to a reliable (quality) list. -- Kheider (talk) 20:55, 19 January 2009 (UTC)[reply]

Flashback (quick reference)-- Kheider (talk) 21:07, 11 March 2009 (UTC)[reply]

Please be careful. If you change an object's radius, please remember to move it up the chart. Serendi^podous 21:33, 11 March 2009 (UTC)[reply]

Will do. :-) Though with some of these changes I feel like I am walking a fine line with {{OR}}. But I guess the values are based on Burton, the current estimated JPL absmag (H), and a generic assumed albedo of 0.09, thus the results are reproducible. Johnston's list is good, but is not always based on the current absmag. -- Kheider (talk) 21:50, 11 March 2009 (UTC)[reply]

It's a bit late to start worrying about that. You've pretty much created the mass and radius figures for every listed minor planet on this site, and, I have no doubt, many of your figures have now entered the media and, perhaps, are even being taken as read by many people who have never looked at Wikipedia askance. You're creating facts as much as reporting them. And while yes that is a bit Orwellian I can't really offer you a better alternative unless the scientific community finally decides to take Wikipedia seriously. Serendi^podous 17:16, 12 March 2009 (UTC)[reply]

To make things scarier some of the pages I have not edited (generally the smaller bodies) do not directly site Johnston and do not show either the size or albedo as "(assumed)". To be accurate a lot of mass estimates have historically been done by Urhixidur, ie see: Sycorax and TC302. Even Ruslik has done a few, see Orcus (Russ assumed a density of only 1.5)... -- Kheider (talk) 18:55, 12 March 2009 (UTC)[reply]

Sorry if that post came across as a bit accusatory. It's not so much meant to reflect on you as on the strange situation Wikipedia's in right now. I wish there was a better alternative, but there isn't right now. All we can do is be sure to clearly state our sources. Serendi^podous 10:36, 13 March 2009 (UTC)[reply]

Thanks for the support. But the truth is, if you have this concern, someday someone else will. At least by showing my math someone can always reproduce or re-do my numbers using a different radius or density. -- Kheider (talk) 15:48, 13 March 2009 (UTC)[reply]

I nominated this list to WP:FLC. Ruslik (talk) 18:22, 3 January 2009 (UTC)[reply]

I was wondering what source you used for the albedo range; I need to cite it for my FLC. Thanks. Serendi^podous 20:15, 20 January 2009 (UTC)[reply]

I based my albedo range off of Johnston's table and what appears to be a common trend for larger TNOs (say 800-1400km range) to have higher albedos than the common "assumed 0.09 value". I am assuming that 2007 OR₁₀ is a little smaller than Sedna. So for bodies 800 to 1400km in diameter I assumed a likely albedo range of 0.15 to about 0.40. Only the very large bodies appear to have extremely high albedos. Not perfect but a good starting point. -- Kheider (talk) 20:46, 20 January 2009 (UTC)[reply]

Who assumes the albedo is 0.09? Serendi^podous 20:50, 20 January 2009 (UTC)[reply]

I am just referring to the Johnston and Wikipedia assumption that a typical TNO has an albedo of 0.09 (and density of 2.0) until proven otherwise. -- Kheider (talk) 20:54, 20 January 2009 (UTC)[reply]

Do you think you could do the calculation assuming an albedo of 0.09 so I could use Johnstone's Archive as a source? Thanks. Serendi^podous 08:09, 21 January 2009 (UTC)[reply]

Sure, but an assumed albedo of 0.09 with an absolute magnitude of 1.9 results in a diameter of 1800. Even Sedna (absolute magnitude 1.6) doesn't really claim to be that big anymore. See: User_talk:Kheider#Diameter_of_Sedna. I would recommend using Ref 6 (Dan Bruton) from the 2007 OR10 article. Then you can properly use "Assuming an albedo of 0.15". -- Kheider (talk) 08:18, 21 January 2009 (UTC)[reply]

All sorted. Thanks again. :-) Serendi^podous 18:07, 21 January 2009 (UTC)[reply]

I noticed that its orbit is surprisingly similar to that of Eris. Semi-major axis is virtually indistinguishable. Ruslik (talk) 10:29, 21 January 2009 (UTC)[reply]

There are some discrepancies between the largest asteroids on this page and the asteroids on the size list. Since neither is cited, I don't know which is right. Serendi^podous 13:31, 23 January 2009 (UTC)[reply]

I would check the main articles. They should be citied. I updated the major asteroids (in late Nov) to reflect Baer's numbers. The "Largest by mass (cis-Neptunian)" section of "List of notable asteroids" does need to be updated. Those numbers are pre-Oct 2008. Baer just gave a presentation at the AAS Division of Planetary Sciences meeting in October. -- Kheider (talk) 15:41, 23 January 2009 (UTC)[reply]

The "Largest by diameter(cis-Neptunian)" section had three objects (532 Herculina, 451 Patientia and 94 Aurora) that weren't on the size list. Their sizes are apparently uncited. I'm not sure about the order, but I don't want to disrupt your work.Serendi^podous 17:09, 23 January 2009 (UTC)[reply]

Yes, those 3 were making me make weird faces back in November: :-)

• In early December (edit), I did update 94 Aurora to show a decent occulation using 9 chords. It showed a size of 225×173 km (geometric mean 197). JPL shows it as 204.89 using IRAS data. So 94 Aurora is in the correct ballpark.
• 532 Herculina: JPL shows 222km per IRAS data. The Institute of Applied Astronomy (2006) also shows 222.19. But I am not sure I want to trust (or suggest to wikipedia) density and mass data from a 2006 source when there have been so many asteroid density-mass changes in the last two years.
• 451 Patientia is listed by JPL as 224.96 per IRAS data. Again the Institute of Applied Astronomy (2006) shows it the same.
  

-- Kheider (talk) 17:51, 23 January 2009 (UTC)[reply]

Red links from List of plutoid candidates (Object, Absolute Magnitude (H), Burton km diameter (generic assumed albedo 0.09):

• 2004 PR107, 4.6, 530
• (82075) 2000 YW134, 4.7, 500
• (145480) 2005 TB190, 4.7, 500
• (144897) 2004 UX10, 4.7, 500
• 2002 CY248, 4.9, 460
• 2002 XV93, 4.9, 460
• 2003 QX113, 4.9, 460
• 1999 CD158, 5.0, 440
• 2002 KW14, 5.2, 400
• 2006 HH123, 5.2, 400
• 2003 UZ117, 5.3, 380

Sorry if this is a burden, but could you check these with Baer? Serendi^podous 16:55, 1 February 2009 (UTC)[reply]

Baer really wouldn't have data on these TNOs. They are basically too far away and too recently discovered. So unless it is a known binary object with a resolved orbit, Baer won't be much help for distant KBOs. These seem to be the red links from List of plutoid candidates. In the past I have converted some of the more standout red links to articles. I will recheck into some of them. But keep in mind you can always get a peak at the object by simply cutting and pasting into JPL or DES.

• With JPL just use the base url code of http://ssd.jpl.nasa.gov/sbdb.cgi?sstr= followed by the provional designation, ie: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2002KW14
• DES is trickier. You will need to remove the first two digits and make sure you don't use a space. So for 2002 KW14 you would use http://www.boulder.swri.edu/~buie/kbo/astrom/02KW14.html With DES once an object has an official MPC number you will need to use that number to get results, ie: Eris needs to be looked up as http://www.boulder.swri.edu/~buie/kbo/astrom/136199.html
  I haven't checked too recently, but most of the above objects are still wildcards as to their status. -- Kheider (talk) 17:43, 1 February 2009 (UTC)[reply]

Ah. So I'd have to calculate it using Bruton, right? Serendi^podous 17:55, 1 February 2009 (UTC)[reply]

I have sorted the above list based on current JPL absolute magnitudes (H) and Burton's formula (assuming albedo 0.09). I rounded the numbers off since these numbers assumed. -- Kheider (talk) 21:39, 1 February 2009 (UTC)[reply]

Sorry for having to take out the dimensions you put; I couldn't find those exact set of numbers anywhere in the tables of Rabinowitz et al. or Stansberry et al.. Feel free to change it back, if you could let me know where they were, or if you prefer we can discuss it instead on the talk page at Haumea. Iridia (talk) 10:43, 3 February 2009 (UTC)[reply]

Rabinowitz 2005 (Table 5) gives a size of 1960x1518x996 (shown as semi-major axes of a₁=980, a₂=759, a₃=498) based on an albedo (P_v) of 0.73. -- Kheider (talk) 15:58, 3 February 2009 (UTC)[reply]

Right, thanks. I was looking at that exact table last night and not connecting their a_x to your figures - must have been half asleep. :P Iridia (talk) 05:02, 4 February 2009 (UTC)[reply]

Was that vandalism or just crazy talk? I dunno. I think if we don't refute their arguments they'll just keep coming. Serendi^podous 18:20, 10 February 2009 (UTC)[reply]

I think the poster was just stirring the pot (vandalism more than crazy). The poster said (1) "Eris would take twenty years to get if traveling at the speed of light" (wrong), (2) "cover ups", (3) "theory is for the planet to come to us and destroy", and (4) "bible". I figured a rv might be called for. It certainly did not look like a legit concern about improving the article itself. -- Kheider (talk) 18:58, 10 February 2009 (UTC)[reply]

I guess I've spent too much time over at Planets proposed in religion and ufology. This pathology runs deeper than you might think. Serendi^podous 19:06, 10 February 2009 (UTC)[reply]

Hey, Could you add something at orbital resonance about resonance orders and the strength of a resonance? I can't tell from your description at Haumea if the resonance gets weaker as the ratio approaches 1 or as it approaches 0; the wording ("the lower the difference") makes it sound like the former, but that would mean a 1:1 resonance is the weakest possible. kwami (talk) 21:20, 10 February 2009 (UTC)[reply]

This pushes what I understand. To make matters more complicated, the 1:1 superresonance is another type of periodic interaction that a 3:2 resonant body can experience in its orbital motion that enhances stability against Neptune. Over 3.7 million years, Pluto's Kozai resonance will make the eccentricity vary from 0.21 to 0.275 and the inclination vary from 14.4 to 17.5. Orcus can get an inclination as high as 23.5.-- Kheider (talk) 22:54, 10 February 2009 (UTC)[reply]

Sorry about that. Don't know why I saved that. Serendi^podous 15:58, 2 March 2009 (UTC)[reply]

I notice you do that when you're attempting to calculate the masses of small objects. Do you also assume that they are spherical? I need to know because I might have to do it. Serendi^podous 16:34, 6 March 2009 (UTC)[reply]

Yes, I use an assumption of a 2.0 density and keep the math simple by assuming a spherical shape. Though I wonder if we should be using an assumed density 1.5 for objects smaller than Pluto. See User_talk:Kheider#Ixion and Ixion (Reference 5). But also keep in mind that 20000 Varuna may have a density less than 1. Planetary Satellite Physical Parameters seems to use assumed densities of 1.5 and 1.3 for moons of Uranus and Neptune. See also: Small Body Density and Porosity: New Data, New Insights. Any thoughts? -- Kheider (talk) 16:56, 6 March 2009 (UTC)[reply]

I don't know. This is one of those situations where Wikipedia's power to seep under the radar into the public sphere can be quite disturbing. Lazy journos (ie all of them) use Wikipedia for quick info, and then Wiki's stats get published in newspapers and magazines as if they're holy writ. I'm not criticising your work (in fact I think you've done a stellar job creating all those minor planet pages), but Wikipedia really needs the authority of an informed professional in these matters, and since informed professionals seem to regard Wikipedia with detached amusement or outright disdain, it's left to us to cobble together what we can from wherever we can get it. So I don't really have a solution, other than to use common sense and work on a case by case basis. For most plutoids, 2.0 is a perfectly valid assumed density, as it it Pluto's density. For comets, a density of less than one would be appropriate, and for asteroids, a density perhaps of 2.5. Not very scientific I know. Serendi^podous 21:43, 6 March 2009 (UTC)[reply]

Good. It sounds like you are thinking along the same lines that I am. It is always good to get some reassurance that I have not wondered into lala land. -- Kheider (talk) 23:28, 6 March 2009 (UTC)[reply]

I think we need to coordinate[edit]

I've been using 2.0 density to complete the top list, and including Earth comparisons, which works somewhat against your point in the introduction, which I hadn't noticed before now. So I think we need to come together on what should be included. Serendi^podous 19:40, 15 March 2009 (UTC)[reply]

For Dwarf Planets Candidates I think a density assumption of 2.0 is fine, and seems to be the normal guess, though 1.5 is a good number also. I am not sure exactly what you are refering to, we are guessing at the density for many of these objects. I used an assumed density of 1.5 for 2060 Chiron because the mass needed to be redone for the higher Spitzer diameter. I also felt it was a good round number and would favor smaller diameters (with a density of 2) for Chiron as well. But it is/was just a guess. I could have as easily gone with a density of 2. But if everything in the solar system had density of 2, we would not need the density or mass column and could just have radius column. I am not sure what line has you concerned. -- 20:29, 15 March 2009 (UTC)

This line: For example if a TNO is poorly assumed to have a mass of 3.59×1020 kg based on a radius of 350 km with a density of 2 g/cm³ and is later discovered to only have a radius of 175 km with a density of 1 g/cm³, the mass estimate would be only 2.24×1019 kg. 350 km radius is above the dwarf planet threshold, so I thought you didn't think the top list should include Earth comparisons. Serendi^podous 20:40, 15 March 2009 (UTC)[reply]

Well like we spoke about above (regarding assumed albedos and assumed densities), we need to be careful. I think we should make it as clear as possible when something is professionally estimated vs when it is just assumed. This is part of the reason I generated the key where ^R and ^M would obviuosly be given a lot of weight, where as with an object like 2007 OR10 your ^P is as good as we can do. My line, "Thus most provisional TNOs are not given a M_Earth value to prevent from cluttering the list with too many assumptions that could be off by an order of magnitude." We could change the wording to say, "Thus caution should be taken with provisional TNOs since their assumed masses could be off by an order of magnitude." -- Kheider (talk) 20:56, 15 March 2009 (UTC)[reply]

I also picked a radius of 350km (likely above dwarf planet lower limit) and 175 km, since an object with a radius of only 175km could easily be a rubble pile. -- Kheider (talk) 21:03, 15 March 2009 (UTC)[reply]

Using the singular does appear to be the standard, so I would. Serendi^podous 10:58, 14 March 2009 (UTC)[reply]

Yes, I'm probably going to include data about Venus-Earth approaches. But if I do, I'll post a spreadsheet or files on my Google account, so you can check for typos.

About the argument that the calculations were OR. Some OR edits do consist of editors making calculations that are not straightforward, and possibly going beyond their ability level. Those are suspect. But in my edits I just got the predictions from a source, which can and should be be judged on its merits, not whether I am using it in an OR manner. And in fact, Solex matches Vitagliano's other long term predictions that are included in Wikipedia. Solex can hardly predict the positions so well at 100k+ years, and not well enough to make these predictions much closer to the present. By the way, the main uncertainty is in the incomplete modeling of the asteroid belt, so like Vitagliano I ran the simulations with and without the big three asteroids, to check for differences the asteroid belt would make. I also tried different starting positions (DE421, DE200, etc), as a check for that uncertainty.

As for whether this all is OR, I argue that using some quality program is the equivalent of getting these numbers from a peer-reviewed article or a source like the Astronomical Almanac because it is also certified by experts to be reliable, and I am using it in its intended manner. OR is about going beyond the sources; this is just the routine uses of one Saros136 (talk) 10:07, 15 March 2009 (UTC)[reply]

Sounds like a good idea. I am not worried about OR here too much, but it is something that we need to keep in mind. See my OR conversation above (regarding assumed albedos and assumed densities.) You can run your numbers, I will check with Horizons and have Frank check with GravSim. If we work Venus the way we did Mercury, I think we will be fine. -- Kheider (talk) 15:18, 15 March 2009 (UTC)[reply]

I'll add the edit soon. Here is the spreadsheet showing those less than 40 Gm from AD 1 onward. Check outthe long gap between 5683 to 65841. Saros136 (talk) 21:40, 16 March 2009 (UTC)[reply]

Horizons only calculates Venus between 3000 BC and AD 3000. And they do not give close approach list for planets. Those are easy to do; get a list of distances by date and use an interpolation formula. I did it for part; the agreement is good. Saros136 (talk) 21:44, 16 March 2009 (UTC)[reply]

Hi Kheider, I'm currently doing a lot of work on this article; I'm hoping to get it up to good article status. You've made more than a few edits there so I was wondering if you'd be interested in helping out.

Cheers, Reyk _YO! 10:10, 15 March 2009 (UTC)[reply]

I would be happy to help. I have also done a lot of edits to the main centaur (minor planet) article since I have been trying to improve the general quality of the centaur related material on wikipedia. -- Kheider (talk) 12:29, 15 March 2009 (UTC)[reply]

Excellent. I have set up a workpage at Talk:2060 Chiron/Collaboration where we can keep our sources and notes organized. Reyk _YO! 21:48, 15 March 2009 (UTC)[reply]

Hey,

Before we start adding stuff to Nice model, let's see if Iridia wishes to do a page move to preserve the article's history. kwami (talk) 19:46, 21 March 2009 (UTC)[reply]

I don't have admin status, so I couldn't move the page immediately: it's up for speedy deletion, so it should be moved over within a day. Iridia (talk) 05:17, 22 March 2009 (UTC)[reply]

Hi, I saw that you're interested in astronomy, and have some expertise in the area of featured articles. Would you be interested in reviewing 243 Ida? Wronkiew (talk) 06:24, 28 March 2009 (UTC)[reply]

Hi again. As you've pretty much asserted yourself as somewhat of an expert on astronomy, I was wondering if you could find a better image of Pallas. I asked on the talk page and got nothing. The one we have is good, but do you know where we could get a less depressing to look at and more educational colored image? Or do you have some idea what it would look like in true color? I'm guessing probably like Ceres or Vesta. I contacted the media director of this article about releasing these images (the detail is much better I think) but didn't get a response, though I could just take 'em a credit the page and author and that they were taken with the HST as I did with the current one. --IdLoveOne (talk) 00:50, 29 March 2009 (UTC)[reply]

Thank you for the compliment. Unfortunately I don't think anyone can do better than Hubble Space Telescope images. Dwarf planet candidates are small objects and this is just the best current technology can produce. I think the current image used in the Pallas article is just a larger (more pixely) version of your 2nd source. They are both based on Schmidt's work. -- Kheider (talk) 17:57, 29 March 2009 (UTC)[reply]

You're welcome! You've really been hustling and contributing a lot, so deserve it. =)

That's a shame about the image, I'm sure there's a true color image of Pallas somewhere in the universe... Oh well. Anyway, can you find anything about its interior? I haven't been very lucky with this. --IdLoveOne (talk) 04:47, 31 March 2009 (UTC)[reply]

Would you mind please updating the dimensions, orbit info and the like per the new Ragozzine and Brown ref I added a few days ago? I'm going to get back there and incorporate the new info from that ref into the article once I've done a bit more on Nice model, but it seems a pity to leave the technical details incorrect in the meantime, and you're good on these things :) Iridia (talk) 07:19, 31 March 2009 (UTC)[reply]

Well, I kinda asked for it after finally blowing my top at Fotaun. I was hoping to woo him back into the fold but he seems to have permanently absconded. Not that I blame him. Anyway, now I have to sort through and source all of Fotaun's mass edits, as well as figure out how to fill the remaining gaps. I have the top list pretty well sorted; all that's required is filling in the blank fields. There are, however, a lot left to do. It's the lower lists I can't figure. What values should I use, do you think? Serendi^podous 16:22, 21 April 2009 (UTC)[reply]

I have nominated Solar System for a featured article review here. Please join the discussion on whether this article meets featured article criteria. Articles are typically reviewed for two weeks. If substantial concerns are not addressed during the review period, the article will be moved to the Featured Article Removal Candidates list for a further period, where editors may declare "Keep" or "Remove" the article's featured status. The instructions for the review process are here.

I noticed that your frequently revert vandalism. To my surprise, I discovered that you do not have rollback! Would not you mind if I assign rollback bit to your account? Ruslik (talk) 19:17, 2 May 2009 (UTC)[reply]

Russ, I appreciate the offer and have considered asking for rollback, but I see myserlf as more of a Wiki-Gnome. I take more pleasure in making tweaks to the articles, then in politics (admins) or engaging wiki-trolls on a daily basis. :-) I like my edit history showing reverts as simply "rv" so that I can properly review my past edits if I wish. But I will let you know if one day I want to attack trolls for fun. Although I do enjoy occasionally making a funny edit summary that I know will make the Warriors come running. :-) -- Kheider (talk) 04:32, 3 May 2009 (UTC)[reply]

Well, if you need this feature (or any other that will be created in the future), you know whom to ask. Ruslik (talk) 08:23, 3 May 2009 (UTC)[reply]

I fully agree with your NPOV-conscious addition (after all, the Gladman’s scheme is not always followed in the same Arizona book). However, the place of your ref is a bit awkward, as the Chiang’s article you quote appeared in the previous collection (Protostars and Planets, 2007) from the same renowned series (University of Arizona Space Science Series). Suggest re-ordering.Eurocommuter (talk) 13:17, 19 May 2009 (UTC)[reply]

Would you be interested in finishing that off with me? I know the job is immensely tedious but I can't do it alone, and now that Fotaun is out of the picture, I have no one to get me started. The attributes of the remaining 200km+ objects, since they're all constant and based on the assumed radius, should be pretty simple (if not easy) to finish. As for the rest I have no idea. This list will have to be filled in, reffed and checked for comprehensiveness. The asterisks will have to be converted to Ref_label format. Before Fotaun went off in a huff (or before I scared him off, not sure which), he seemed to be intent on making the list comprehensive for objects above 50km in radius. I have no idea if he succeeded. Serendi^podous 20:36, 25 June 2009 (UTC)[reply]

I can help. but I am not sure I will be hitting it aggressively. -- Kheider (talk) 09:24, 27 June 2009 (UTC)[reply]

I am not against participating too. Ruslik_Zero 18:34, 27 June 2009 (UTC)[reply]

I just finished the 200+ sortable table, so at least this page is, to a certain extent, useful. Do you have any ideas on where I could go to finish and cite this monster? Serendi^podous 11:01, 1 October 2009 (UTC)[reply]

You mean cite the volume, mass, gravity or just cite the diameter? I think we can only cite the diameters and for a lot of the KBOs we are obviously using assumed values. I think the IRAS values (currently ref 13) and a generic JPLDATA call might be the best we can do. For the volume, mass, and gravity of the poorly known objects we can only let people known that generic internal wiki formulas were used. -- Kheider (talk) 12:00, 4 October 2009 (UTC)[reply]

Problem is that beyond the 200km radius boundary, we can't be certain we are dealing with spheres, so calculating mass from diameter is risky. I don't know what to do but it seems a bit haphazard leaving the lower lists so riddled with gaps. Do you think this list could ever be featured, as the Solar System FT demands? Serendi^podous 12:34, 4 October 2009 (UTC)[reply]

Spheres more accurate? Most of the KBOs are just best guesses at their diameters (within a factor of 2). I suspect the "spherical calculations" for the non-spherical asteroids are more accurate since the diameters are generally better known. The article could only be featured with the proper disclaimers about the lack of knowledge of these small bodies. I don't think anyone has ever attempted such a comprehensive list. -- Kheider (talk) 08:20, 5 October 2009 (UTC)[reply]

Truly sorry, I think I was a bit too bold in using AutoEd. I guess the error came from removing a self-reference within the article. Thanks for the warning Dr. Breznjev (talk) 19:14, 16 July 2009 (UTC)[reply]

Well, this is another example why I should be extra careful when editing scientific articles with mathematical or astronomical subjects. In the mean time, I have repaired another mistake. Thank you! Dr. Breznjev (talk) 19:28, 16 July 2009 (UTC)[reply]

http://www.solarviews.com/cap/jup/leda.htm says that the image is in the public domain. (It is created by NASA/JPL). Ruslik_Zero 19:14, 10 August 2009 (UTC)[reply]

I found this page, which contains additional information, but I was unable to find anything else. The Science's articles about V1&2 encounters with Jupiter do not have this image. The only way to discover the truth may be to ask Palomar directly. Ruslik_Zero 09:59, 11 August 2009 (UTC)[reply]

It is also possible to ask Hamilton, where he took this image from. Ruslik_Zero 10:00, 11 August 2009 (UTC)[reply]

According to Wikipedia:Image_use_policy#Free Images "Wikipedia only" licenses are not acceptable. The license should be one of those listed on Wikipedia:Image_copyright_tags#For image creators. If the image is not released under one of those licenses it should be deleted or, alternatively, it can be used as WP:Fair use image. Ruslik_Zero 08:16, 12 August 2009 (UTC)[reply]

Does that happen often? I came back this morning to find the page slapped with an autoprotect. Seemed a bit rough - he'd done nothing to that page that was unconstructive. --Iridia (talk) 03:24, 13 August 2009 (UTC)[reply]

Hi! Well, afair this image comes from en.wikipedia, I just moved it to Commons. In my opinion the best way is to contact with Scott Sheppard via mail from his website and take permission for this and other images and send it to OTRS. I don't have any 'astronomic' experience, so if you can contact with Mr. Sheppard I will be grateful :). Yarl ✉ 10:53, 13 August 2009 (UTC)[reply]

"The definition of a detached object has even recently changed..."^{[citation needed]} Nergaal (talk) 16:41, 15 August 2009 (UTC)[reply]

While adding an external link (to my website describing precovery astrometry) for this object, I took the opportunity to correct the upcoming perihelion date. You reverted it, saying that the "Orbit not determined well enough to pindown the exact day". As a result of my precovery work, involving the finding and measuring of images from nine plates at seven oppositions back to 1980, this TNO has now been observed for a total of 28 years, and the orbit is very well known and the date of perihelion is known to within one day. I even got the opportunity to account for planetary perturbations, so that my perihelion date of November 1, 2096, is based on osculating elements from the same date. Just thought you might want to know the background to my edit.. Lowe4091 (talk) 23:14, 23 August 2009 (UTC)[reply]

Hi Kevin, regarding your note about using DSS images within Wikipedia, the following guidelines might be of interest: http://www.stsci.edu/institute/Copyright Lowe4091 (talk) 16:43, 24 August 2009 (UTC)[reply]

Great work for getting approval for 2007 UK126! Take any of my other images: http://members.shaw.ca/andrewlowe/tno-precoveries.htm Lowe4091 (talk) 19:11, 25 August 2009 (UTC)[reply]

Hi Kevin, that upper star in the image for 2007 UK126 is mag. 14.1 Lowe4091 (talk) 19:35, 25 August 2009 (UTC)[reply]

		The Space Barnstar
		For tenacious knowledge of astronomy and contributions to astronomy articles. I′d※<3※Ɵɲɛ (talk) 07:04, 5 November 2009 (UTC)[reply]

Such as this edit summary... classic. Cheers, and thanks for the laugh. --Ckatz^chat_spy 17:49, 12 November 2009 (UTC)[reply]

I have a reduced HST image of Orcus/Vanth lying around on my hard drive. Though figuring out which orbit I got it from might be a bit more tricky. HST data is fine to go on Wikicommons, yes? Iridia (talk) 22:58, 16 November 2009 (UTC)[reply]

because I wish I could do it myself, but could you name Weywot, please? Serendi^podous 11:43, 17 November 2009 (UTC)[reply]

 Done. -- Kheider (talk) 09:05, 20 November 2009 (UTC)[reply]

Thank you :) Serendi^podous 13:25, 20 November 2009 (UTC)[reply]

Apropos your quick repost to my discussion on the apparent visual magnitude for Mercury.

You are at liberty to do the calculations and to ignore the extremes, as you put it. The following may be of interest.

John C. Vetterlein
J. Br. Astron. Assoc. 116, 5, 2006:
It is not generally appreciated just how bright Mercury appears when close to superior conjunction. It is interesting to compare the two events this year when Mercury and Venus both reach superior conjunction. On 2006 May 18, Mercury was at magnitude –2.3. When compared to the data for Venus at superior conjunction on October 27, we find that the surface brightness per unit area will be almost identical for both planets. Put another way, Mercury would be at magnitude –3.7 if it had the same apparent diameter as Venus. (Venus on October 27 will be at magnitude –3.9.) There are times in fact when the surface brightness per unit area for Mercury outdoes Venus herself. Naturally, when Mercury is close to inferior conjunction it is both faint and too close to the Sun to even attempt an observation.

I have been an observer of Mercury for over fifty years. -- 86.167.31.80 (talk) (aka Wilberfalse (talk)) 11:34, 26 November 2009 (UTC)[reply]

JPL Horizons shows Mercury at apmag –2.4 on 2006-May-18 04:45UT, but of course Mercury is only 0.79° from the magnitude –26 Sun. When Mercury is 4° from the Sun it is only mag –1.9. Perhaps we should change the range to show "–2.3 to 5.7" (May 28 2002) -- Kheider (talk) 18:41, 26 November 2009 (UTC)[reply]

There's a clarify tag in the Mass section of Halley's infobox, but I'm not entirely clear what it's saying. Is it saying that we have no idea at all what Halley's mass is? Since this falls under your jurisdiction I thought I'd ask you before making any further assumptions. Serendi^podous 22:02, 26 November 2009 (UTC)[reply]

I am not sure what clarification they want in an estimate. In Comet_nucleus#Size I make it clear that I assumed a density of 0.6 based on Sagdeev1988 with an approximate ellipsoid size of 15×8×8km. But I guess we could use: 4×10¹⁴ kg (?) ==> Using the volume of a sphere of 11km * an assumed rubble pile density of 0.6 g/cm³ (typical of comets) yields a crud