Talk:4 Vesta

Density

Following [1] (Jan 9, 1998) the density of Vesta is only 3.9 ± 0.3 grams per cubic centimeter. Is this more recent/fiable than the current value of 3.3g/cm3?

Thomson et al. (1997) gives a mean radius of 258 km and Michalak (2000) a Mass of 1.36 ± 0.05 × 10–10 Sun masses. Based on this, Keil (2003) gives a density of 3.8 g/cm^3 -- Epo 10:44, 17 Mar 2004 (UTC)

The old density estimates of even 5.0 or so were based on the IRAS diameter which was far too small. Based on the newer HST data of Thomas [Science 277, p 1492, (1997)], the dimensions are 578x560x458 km ± 10 km, so a geometric average of 529 km, giving a volume of about 7.8±0.4×10¹⁶ m³. The latest mass estimate of Pitjeva (ref in article) gives about 2.67×10²⁰ kg, with maybe a 15% uncertainty by comparing to other people's results. This then gives a best estimate of density of 3.4 ± 0.5 (the uncertainty is kind of uncertain). Deuar 08:43, 13 November 2005 (UTC)

Rewrite

I reworked the whole article -- please somebody check the grammar since my Engrish is not perfect Jyril 21:27, 22 Jun 2004 (UTC)

After reading through a few papers on the topic, i've tried to put what i've gleaned into the article before I forget it or lose the notes ;-). The end result seems to have been a major reorganisation. Deuar 21:05, 13 November 2005 (UTC)

History

Needs some expansion on the discovery, and it's former status as a planet... The fact that it's visible to the naked eye seems like it only had bad luck not being picked as a classical planet. Tesseract501 March 23, 2006.

Needs some expansion on the discovery. Michaelbusch 18:08, 17 Aug 2006 (UTC)

Ceres is still the largest asteroid even though Ceres is also a 'dwarf planet'. Pluto is a Kuiper Belt Object (KBO) even though it is also a 'dwarf planet'.

Diameters

Regarding the Diameter: What does the third measurement (for irregular shapes) indicate? Am I correct to assume that the first measurement indicates the longest axis at the equator, and the second measurement the polar axis? If so, is the third measurement the secondary equatorial axis (at right angle form the longest equatorial axis)? Or is it the mean diameter or something else? Thanks ---- Tesseract501 March 23, 2006.

I believe it's standard for it to be at right angles to both. kwami 23:59, 23 March 2006 (UTC)

Thank Kwami. I checked out the info on several other planetoids. The values seem to indicate Triaxial Ellipsoid Dimensions (geometric measurements for irregular objects). From what I can tell, the three numbers only fall in order from longest to secondary to shortest diameter. Whether or not any of the three happen to be the equatorial or polar diameters may be uncertain. It gets even trickier because some asteroids may rotate in more than one direction (wobbling) because of their irregular shape and composition. So I don't know how someone could find that kind of data for the major known asteroids. I haven't found any sources to tell us what the equatorial(s) and polar(s) diameters are for specific asteroids. By the way, whoever put together the data on all the various asteroids did an AMAZING, SUPER JOB. It must be full-time work to keep them all updated. ---- Tesseract501 March 24, 2006.

A hunt for "most out of date solar system body" could be fun ;-) Deuar 16:55, 26 March 2006 (UTC)

For rotation to be stable over long timescales, the shortest DEEVE diameter must correspond to the axis of rotation and the two others are the major and minor axes of the ellipse formed by the DEEVE's intersection with the equatorial plane. Obviously, all three are at right angles to each other. Almost all objects in single-axis rotation, not tumbling (we can measure this by lightcurve and radar), so we can define the axes properly. 'DEEVE' stands for dynamically-equivalent equal-volume ellipsoid. It is an ellipsoid with equal volume and equal moments of inertia to a given asteroid. Such an object has the same mass, volume, and density as the target asteroid and is the standard for computing tri-axial ellipsoid dimensions. Michaelbusch 16:03, 17 August 2006 (UTC)

Physical Characteristics

Next to "Mean surface temperature", on the Physical Characteristics table, the min and max temperatures are given, the temperature Extremes for "4 Vesta", but not the actual "Mean surface temperature" for the asteroid. Obviously, the mean is easy to calculate, even for my little brain, from the min and max data but still there is an inconsistency in this table. Actually, I find the min max temperature more interesting data than just the mean by itself.

We cannot specify a mean temperature by taking the average of min and max, because we don't know the distribution of temperature across the surface of the asteroid. Even the min and max are uncertain, particularly the minimum (because we have little data on the nightside). We can calculate an average temperature for the surface by taking the albedo and average cross-section, using those to compute the total solar energy incident, then dividing that by the effective surface area of the object to get the mean power radiated per unit area. However, this is not the same as a geometric mean across the surface. Michaelbusch 16:03, 17 August 2006 (UTC)

Fragments

Could someone elaborate on how we know the meteorites originated on Vesta, and not some other asteroid? Gary 04:51, 20 August 2006 (UTC)

The spectra of the V-type asteroids, as well as the HED meteorites, match Vesta's very distinctive spectrum. The meteorites probably didn't come directly from Vesta, but we can assume that they have been through a similar history (see the physical properties section) Michaelbusch 16:20, 20 August 2006 (UTC)

• it is the same process as we know ALH84001 is from Mars. I just read about Vesta and those meteorites probably did originate in Vesta, Vesta was hit by a massive impact which destroyed part of it (that is why it is "half round, half not"). Vesta remains even reached Earth! So Vesta and Ceres are seen by leading planetologists as mini-planets and protoplanets, not as asteroids.-Pedro 22:25, 7 September 2006 (UTC)

In addition the debris form 4 Vesta's great polar crater should be a rich source of terrestrial meteorites, "about 5 percent of all meteorites we find on Earth are a result of this [Vesta's polar crater] single ancient crash in deep space."[2] Pulu (talk) 23:38, 29 July 2011 (UTC)

GA

Good article, keep up the good work -- Nbound 00:54, 17 September 2006 (UTC)

Symbols

I've added a little more information, but I'm not sure where to link for MPC numbers. Please help! Adam Cuerden ^talk 23:52, 4 October 2006 (UTC)

...Weel, it was deleted. Still, it WAS accurate and cited, (and involved a fair bit of work to make the new symbol) so I paste the cut text here if anyone sees a better way to work it in. It starts just after the opening as it stands now.

When designated by a symbol it is usually , but it is sometimes Old symbol of Vesta or Old planetary symbol of Vesta. All are simplifications of the original rather more detailed hearth, . The difficulty of drawing the symbols for the asteroids from Vesta onwards led to B. A. Gould suggesting a numbers in circles to be used instead, which would eventually simplify to the number in parentheses: (4) Vesta, and then finally to just the number: 4 Vesta - in short, the MPC number system used for all minor planets today. [3])

I thought it was fascinating. I'm not sure why it needed to go. --Aranae 02:27, 5 October 2006 (UTC)

My rational for the original deletion of the more detailed description of the history of the symbols was twofold: one that it was uncited (this has been fixed) and two that, while it is interesting, it was somewhat long and does not relate to the remainder of the article (because symbols are very rarely used, and almost never for asteroids). It might be appropriate in one of the articles dealing with the history of astronomical terminology. If there is consensus for keeping the material, let it be decided here. Michaelbusch 02:32, 5 October 2006 (UTC)

The only reason why I added the symbols to the body of the article was because I reduced the symbols at the top of the infobox down to just one, and some people complained about the same thing being done on 1 Ceres. Not only are asteroid symbols virtually unused in the astronomical world, but the astrological world pretty much only uses the one in the infobox. I'd cut it right down to "When designated by a symbol it is usually " if there weren't objections. _└ ^OzLawyer / _talk ^┐ 03:08, 5 October 2006 (UTC)

Er... actually, that cite was there from the start. Still, the main body of information probably ought to go in an article on Minor Planet Number - who wants to join me in writing one? Adam Cuerden ^talk 06:45, 5 October 2006 (UTC)

Er...actually, it wasn't. _└ ^OzLawyer / _talk ^┐ 12:36, 5 October 2006 (UTC)

It was, at least from when I added the controversial part. Not that it matters that much.

Yes, clearly it was there when you added to it. My point was that if I hadn't added it in the first place, the article might have continued without any discussion about the symbol, which I actually think is better. At the most, it needs just a note that the symbol at the top of the infobox is the most common of several symbols for the asteroid. _└ ^OzLawyer / _talk ^┐ 14:21, 5 October 2006 (UTC)

Sorry about that, got confused and was sttressing out a bit over an oral report at the time. Adam Cuerden ^talk 18:11, 5 October 2006 (UTC)

Largest asteroid

According to http://www.iau2006.org/mirror/www.iau.org/iau0603/iau0603_Q_A2.html , Ceres is no longer an asteroid. 132.205.44.128 05:15, 13 November 2006 (UTC)

I was the one who originally posted that reference... please see my reply to your post here. Thanks! --Ckatz^chat_spy 05:59, 13 November 2006 (UTC)

You can also see Talk Ceres and Talk kheider. I believe that Ceres is still an asteroid until an official statement is released. A poorly worded press release is not very reliable. Vesta may be a Dwarf Planet Remnant, and thus may not be an asteroid *IF* (1) the rule: "Once a dwarf planet, always a dwarf planet" is applied and (2) Dwarf Planets are not asteroids. -- Kheider 15:06, 13 November 2006 (UTC)

Sorry if my post wasn't clear... my link to "here" points to the discussion at Talk Ceres as well, since 132.205.44.128 posted a similar question there. --Ckatz^chat_spy 20:01, 13 November 2006 (UTC)

Actually that points to Talk Asteroid. So yes, the conversation is in multiple locations. :-) -- Kheider 19:36, 14 November 2006 (UTC)

Yes, well, I learned to read at a very early age, before all this new-fangled A-B-C stuff came about... 8) --Ckatz^chat_spy 21:32, 14 November 2006 (UTC)

Color image

A color image of Vesta is available:

http://hubblesite.org/newscenter/archive/releases/2007/27/image/c/

— RJH (talk) 21:37, 20 June 2007 (UTC)

As a Hubble image it's not PD. Is there a fair use rationale that applies? Lexicon (talk) 22:34, 20 June 2007 (UTC)

Please see http://hubblesite.org/copyright/ for Copyright information regarding hubble pics. Accroding to their copyright notice, this one is PD or FUR. Abyssoft 11:44, 21 June 2007 (UTC)

Occasionally Ceres can come closer to the Sun than Vesta

You can not allows easily diagram 3 dimensional space on a 2 dimensional drawing.

• For example look at the JPL orbital simulation for 887 Alinda. When you first load it, it looks like 887 Alinda crosses the orbit of Earth. But if you drag the bar on the right to the bottom, you will see that this asteroid does not cross Earth's orbit. Since it has a perihelion (closest distance to the Sun) of 1.07AU it does stay outside of the Earth's orbit.
• Another good example is Pluto. If you load the JPL orbital simulation for Pluto, zoom in some, and rotate to the left you can make it appear as if Pluto always stays further from the Sun than Neptune.
• If you look at JPL's 2-body orbital simulation for Ceres and Vesta and move forward to 2009-02-10, you will see that Ceres is closer to the Sun at that time. Vesta 2.56AU; Ceres 2.54AU. -- Kheider (talk) 17:03, 31 May 2008 (UTC)

mass

A hidden comment showed the mass as having 4 sig figs, so I changed the info box to match. However, I don't have access to the article. 4 seems awfully precise. Can someone confirm the error? Even in the abstract it's clear that there's at least 3 sig figs, and we only had two. kwami (talk) 14:37, 4 November 2008 (UTC)

The mass of Vesta as listed in Pitjeva, 2005 is 1.344 ± 0.001 mass of Sun. Ruslik (talk) 15:11, 4 November 2008 (UTC)

Good, thanks. Just wanted to check. kwami (talk) 15:20, 4 November 2008 (UTC)

Actually the masses of the major asteroids are still poorly known. A lot of it depends on the true mass of Ceres and Pallas. Of the large asteroids, Vesta appears to have the best known mass. Some non-PDF reading: Asteroid Masses and Densities, Hilton (Masses of the Largest Asteroids), New determination of the mass of Pallas -- Kheider (talk) 15:38, 4 November 2008 (UTC)

GA Reassessment

This discussion is transcluded from Talk:4 Vesta/GA1. The edit link for this section can be used to add comments to the reassessment.

This article has been reviewed as part of Wikipedia:WikiProject Good articles/Project quality task force in an effort to ensure all listed Good articles continue to meet the Good article criteria.

Overall, this article is very well-written and, for the most part, well-referenced. Comprehensiveness, neutrality, stability, and images are all fine. A few concerns came up during my review:

1. One or both of the lists in the "Geology" section may work better as prose.

   I think some sort of geometrically sequential arrangement is appropriate, as both indicate sequences. I think prose would be much harder to follow, especially for someone trying to skim the article. However, I do agree that the list format is not the greatest for legibility. I've converted to tables. They may need some adjustment, but see what you think. kwami (talk)

2. The last paragraph of the "Geology" section (the thickness of the crust) should be referenced.

   done Nergaal (talk) 00:28, 16 November 2008 (UTC)

3. Near the end of the second paragraph in the "Surface features" section, a reference is placed directly after "Hubble images". References should normally be placed after punctuation to make it clear what they are referencing. Does this cover the information before the reference, after the reference, or both?

   "Interestingly Vesta was not disrupted nor resurfaced by an impact of this magnitude." is a non-sequitour. Nergaal (talk) 00:28, 16 November 2008 (UTC)

4. Likewise, in the final paragraph of that section, does the reference cover the entire paragraph?
5. The "Exploration" section should be referenced.
6. In the "Exploration" section, Dawn is italicized the first time but not in subsequent mentions. Is there a reason for this?

   Nope. All now cap'd. kwami (talk) 19:07, 5 November 2008 (UTC)

7. Can more information be provided for Reference 26?

   Done. kwami (talk) 09:30, 6 November 2008 (UTC)

I will place this on hold for a week to allow for these concerns to be addressed and/or discussed. If progress is being made, an extension will be granted if necessary. Any questions and/or comments can be left here, as I have placed this page on my watchlist. Best wishes, GaryColemanFan (talk) 18:32, 5 November 2008 (UTC)

Interesting note: While looking for sources for the "Exploration" section, I came across this article published by Reuters. Facts #2 and 3 looked familiar, so I checked an old revision of Wikipedia's 4 Vesta article (http://en.wikipedia.org/w/index.php?title=4_Vesta&oldid=160069737, last edited three days before the Reuters article). It turns out that Reuters copied them and pasted them directly from here. GaryColemanFan (talk) 03:39, 9 November 2008 (UTC)

Thanks for warning me about the possible de-listing GaryColemanFan, I've been busy with other projects off of Wikipedia. I'll get right to assisting with the assessment. --IdLoveOne (talk) 23:29, 20 November 2008 (UTC)

In Favor per Wikipedia:Reviewing good articles:

• The article is NPOV
• No cleanup requested
• No edit wars appear to be going on
• I observe no grammatical errors
• Clearly written and broad in coverage in regards to the topic
• All images tagged and licensed and usage is allowed

However I'm not sure what wiki's standard is about it being "current" but obviously the Dawn mission justifies that a bit, and I don't know if all the links are reliable, can someone else check this or tell me how to do it?--IdLoveOne (talk) 03:10, 21 November 2008 (UTC)

I will try to fix remaining issues today. Ruslik (talk) 04:35, 21 November 2008 (UTC)

Fixed 4 and 5. Ruslik (talk) 08:44, 21 November 2008 (UTC)

I've cleaned up the references (yet again), and addressed the remaining points. Looks good to me now. Urhixidur (talk) 15:50, 21 November 2008 (UTC)

Q. Is the following paragraph really needed in an article about Vesta?

NASA attempted to cancel Dawn in 2006, citing budget pressures and technical issues, but scientists appealed and won an additional $100 million to continue the program. Total mission costs will now be about $450 million.

Thanks.—RJH (talk) 16:13, 21 November 2008 (UTC)

In response to RJH, the total cost of the mission doesn't seem particularly important. Since there was no soucred provided, I removed that sentence and combined the final two paragraphs.

All of my concerns have now been addressed, so I am going to close this reassessment and keep this article listed as a GA. Thanks you to everyone who helped, GaryColemanFan (talk) 18:30, 21 November 2008 (UTC)

Thanks. Good job!—RJH (talk) 18:49, 21 November 2008 (UTC)

Good, but what about Pallas, Hygiea and Juno? --IdLoveOne (talk) 21:52, 22 November 2008 (UTC)

I have already performed recent GA reassessments of Pallas and Juno, and both articles retained their GA status. Because Hygiea was listed as a GA after August 2007, it is not included in the first round of GA sweeps. GaryColemanFan (talk) 22:17, 22 November 2008 (UTC)

error ranges

Can s.o. add the error estimates for the diameters? I don't have access to the ref. Even with the PD error bars for Pallas it's clear the two overlap, but it would be nice to be accurate rather than just precise. kwami (talk) 01:20, 18 November 2009 (UTC)

You could also use either Baer2008 ==> Baer, James (2008). "Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris" (PDF). Celestial Mechanics and Dynamical Astronomy. 100 (2008). Springer Science+Business Media B.V. 2007: 27–42. doi:10.1007/s10569-007-9103-8. Retrieved 2008-11-11. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help) OR Baer2009 ==> Jim Baer (2009). "Recent Asteroid Mass Determinations". Personal Website. Retrieved 2008-12-06. The Hubble reference is from 1997. -- Kheider (talk) 02:47, 18 November 2009 (UTC)

the time of less favorable oppositions

The synodic period of 4 Vesta is about 1.38 years. So for an opposition on a particular date, the 3rd, 5th and 8th following oppositions will be at close to the same calendar date. The less favorable oppositions that were tagged with a when template and "What year?" comment recur whenever the opposition happens in late autumn. With my calculator I get oppositions near Nov. 18th on 2012, 2016, 2019 and 2023. A planetarium program could give exact dates. I am not sure what is best to put into the article. --Fartherred (talk) 04:46, 17 October 2010 (UTC)

With Horizons I get: (Date, Distance, Sun-Earth-Vesta angle)
2012-Dec-07 1.589AU 173.96°
2017-Jan-18 1.522AU 177.13°
2019-Nov-13 1.565AU 170.49°
-- Kheider (talk) 07:17, 17 October 2010 (UTC)

Interior of Vesta

There is a good article at the Max Planck Society discussing some new findings about the interior of Vesta. Link The original article is from Icarus through Elsevier and is located here. --Xession (talk) 04:26, 7 January 2011 (UTC)

Only remnant protoplanet

Claiming 4 Vesta is the ONLY remnant protoplanet is a bad idea in IMHO. The Kuiper belt likely has many such objects. 4 Vesta may be the only remnant protoplanet in the asteroid belt, but I also think Ceres and 2 Pallas can claim to be protoplanets. -- Kheider (talk) 18:20, 7 January 2011 (UTC)

The physorg.com article cites Reddy et al. (2010). Perhaps somebody could check there to see what they really stated? I don't have access to Icarus.—RJH (talk) 18:52, 7 January 2011 (UTC)

The Max Planck Society article used as reference (#11 MAX) does list Dr. Andreas Nathues (one of the authors) as a contact so I trust it more than physorg. But like yourself, I do not have access to Icarus. -- Kheider (talk) 20:04, 7 January 2011 (UTC)

All three big asteroids have been called "protoplanets". And Vesta but not Ceres?

Season at DAWN?

What will the vestan season be when DAWN arrives? The visit will be only 0.2 vestan years, so there won't be a lot of change if one hemisphere is in winter. — kwami (talk) 14:27, 7 February 2011 (UTC)

Vesta doesn't have a significant atmosphere, so I'm not sure what type of change you are expecting. Please could you clarify?—RJH (talk) 16:42, 7 February 2011 (UTC)

The season could affect which areas of Vesta are illuminated or not while Dawn is in orbit. --Patteroast (talk) 17:44, 7 February 2011 (UTC)

That's true. Thanks.—RJH (talk) 19:39, 7 February 2011 (UTC)

Yes, that's what I was wondering: how much of Vesta will we actually see? Will the southern crater be visible? What about the expected compression fractures at its antipodes? — kwami (talk) 21:03, 7 February 2011 (UTC)

I can't seem to find the paper discussing the Framing camera in short order, but it is capable of imaging in the near-IR (see here). There is also a visible/infrared spectrometer that will provide colorful maps many will be familiar with from recent missions to the Moon. The mission won't likely leave much, if any, of the surface on either Vesta or Ceres unmapped. --Xession (talk) 21:12, 7 February 2011 (UTC)

Yeah! Southern summer! Just heard back from NASA. No citable source, so I hope you don't mind me just adding it to the article. — kwami (talk) 20:11, 10 March 2011 (UTC)

Dead link

During several automated bot runs the following external link was found to be unavailable. Please check if the link is in fact down and fix or remove it in that case!

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--JeffGBot (talk) 14:11, 19 June 2011 (UTC)

Dead link 2

During several automated bot runs the following external link was found to be unavailable. Please check if the link is in fact down and fix or remove it in that case!

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Dead link 3

During several automated bot runs the following external link was found to be unavailable. Please check if the link is in fact down and fix or remove it in that case!

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--JeffGBot (talk) 14:11, 19 June 2011 (UTC)

puzzled

I'm puzzled. In the image from July 17,

,

the southern hemisphere is half in shadow. But on July 9,

,

it was fully illuminated. Vestian seasons don't change in a week, and rotation shouldn't make any difference, so what's going on? Or is that not the southern crater that we're seeing? — kwami (talk) 22:36, 18 July 2011 (UTC)

The Dawn spacecraft, which took both images, was still en route to Vesta on July 9, but is now orbiting around it. The movement of the spacecraft itself is what caused the shadow change. LittleMountain5 22:44, 18 July 2011 (UTC)

Thanks, but I don't understand. The position of Dawn should have no impact on which areas of Vesta are illuminated. — kwami (talk) 22:50, 18 July 2011 (UTC)

Oh, I see. I'm not entirely sure why the the illumination of certain areas on Vesta have changed... probably due to its quick rotation (about five hours) and axial tilt (about 29 degrees). I'm no expert, though. LittleMountain5 22:57, 18 July 2011 (UTC)

Yeah, but AFAIK that peak is at the south pole. Axial tilt would matter, but only on the scale of years as southern winter approaches. Over the course of a day the terminator would rotate around the world, but it shouldn't approach or recede from the pole. Unless what we're seeing is not the southern hemisphere, but then I have no idea where we are on Vesta: Do we have a second global-scale crater on Vesta? — kwami (talk) 23:01, 18 July 2011 (UTC)

As far as I can tell from comparing the two images, we are indeed looking at the same massive crater on Vesta's southern hemisphere. (Notice the three smaller simple craters on the upper middle of the newer image and the lower left of the older image.) The giant crater isn't exactly centered on the south pole (see this image), so maybe that accounts for the deviation? LittleMountain5 23:16, 18 July 2011 (UTC)

If you rotate the July 11 image by about 130 degrees clockwise, you can see that the smaller craters line up with the July 17 image. Fromthe shadows in those craters, you can then see that the Sun has changed position by nearly 180 degrees. So I think that big mound in the middle of July 17 is near the equator. That's gotta be one huge peak, from the floor. Tbayboy (talk) 23:08, 18 July 2011 (UTC)

Actually, playing with the images, it's more like 150 degree image rotate, to get maybe 120 degrees change in Sun angle. So the craters along the lip of the crentral mound look like mid-latitude, so the crater itself looks like it encompasses a pole. From this angle, Vesta really pushes the question of "how round is round?". Tbayboy (talk) 23:31, 18 July 2011 (UTC)

So we have a polar crater, but with a mid-latitude peak within it? Is there maybe an outer wall that encompasses more than the flat spot at the pole? Reconstructions from Hubble show a polar peak as well. I guess I'll have to see the thing mapped. — kwami (talk) 23:38, 18 July 2011 (UTC)

This image is captioned as centered at 55°S. The mountain isn't in the center of the image, though. But this sure does look like the peak seen in Hubble images. I'd just always assumed that was at the pole due to angular-momentum constraints. — kwami (talk) 01:12, 19 July 2011 (UTC)

They're fascinating images. What seems curious to me is that the surface is not fully saturated with crater impacts. All of the impacts I can see look fairly fresh (non-worn). It appears as if the asteroid has been significantly resurfaced with what appears to be an ejecta blanket (or some other process). But that's just my non-expert speculation. It'll be interesting to get a good look at the south pole impact site. Regards, RJH (talk) 15:18, 19 July 2011 (UTC)

The polar impact is thought to have been less than a billion years ago. That would have resurfaced the entire world.

And evidently NASA will extend the mission until they can get a good look at the north pole too, for the expected compression fractures. — kwami (talk) 18:48, 19 July 2011 (UTC)

Dawn quibble

"After orbiting Vesta for approximately one year, in July 2012 Dawn will proceed to its other target, Ceres. This is possible, as the spacecraft is the first that can enter orbit around more than one body as a result of its weight-efficient ion-driven engines.[45]"

Is this the main reason actually the engines, or is it at least as much that the very low gravity enables the craft to escape orbit so much more easily than from say a planet? 109.153.234.156 (talk) 23:23, 18 July 2011 (UTC)

The engines. Dawn could escape from a planet too, it would just take longer (and more fuel). But AFAIK a traditional rocket would be incapable of doing what's planned for Dawn. That's what got this thing funded: no-one cared enough about asteroids to actually fund a mission, but they would fund an asteroid mission in order to demonstrate the abilities of the ion drive. — kwami (talk) 23:40, 18 July 2011 (UTC)

Oh OK, thanks for confirming it. 109.153.234.156 (talk) 23:59, 18 July 2011 (UTC)

Yeah, Dawn's accelerated more under those engines than any rocket ever has. And it's not done yet. I just hope there's enough fuel left to break Cererian orbit and make a flyby of Pallas. — kwami (talk) 01:21, 19 July 2011 (UTC)

rotation clip

does anyone have access to the rotation clip they showed today? That would be an awesome header image, like we have for Pluto.— Preceding unsigned comment added by Kwamikagami (talk • contribs) 00:36, 2 August 2011 (UTC)

You can download it here, but I don't know how to convert it to OGG, the required video file type. LittleMountain5 00:59, 2 August 2011 (UTC)

I can convert to ogg, but not with the codex they want, because firefog is not compatible w v. 5. I'll ask for help. — kwami (talk) 01:46, 2 August 2011 (UTC)

I also figured out how to convert it to OGG (with the correct codex), but upon looking at Pluto's example again, I realized it's an animated GIF. Making something like that would require either finding each separate image NASA used in their video, or taking frames from the video itself. I'll try to work on it tomorrow. LittleMountain5 02:31, 2 August 2011 (UTC)

The high-def version really makes a big difference, but I don't know how practical it would be. — kwami (talk) 04:32, 2 August 2011 (UTC)

I tackled the harder one first: here's the animated GIF. Note that this is the first time I've ever made an animated GIF, so suggestions for improvement are welcome. Cheers, LittleMountain5 00:54, 3 August 2011 (UTC)

Beautiful! It's large, but even with a slow connection it will display a perfectly good image while it continues to download. — kwami (talk) 01:04, 3 August 2011 (UTC)

Yeah, I tried to make it as big as possible to preserve at least some of the detail. Do you think it's a good speed? I animated a little faster than the video so it rotated more smoothly, but now I'm second guessing myself. LittleMountain5 01:08, 3 August 2011 (UTC)

The speed is fine. It's going to be much slower anyway as it loads. I was hoping for full res, but see now that that would be unmanageably large, and the detail is pretty good as you have it. — kwami (talk) 01:40, 3 August 2011 (UTC)

Provisional map, though only ±30°, so I don't know if it's worth uploading. — kwami (talk) 05:21, 2 August 2011 (UTC)

This is now officially the coolest infobox photo of all articles in all Wikipedias.--Cam (talk) 15:11, 6 August 2011 (UTC)

Name explain - Why 4?

A casual reader should be offered an immediate answer to the obvious question, What does the 4 in the name mean? A reader with more interest should be offered a detailed history of the name, and particularly when the modern name was first used, and when the modern form became the dominant form of reference.-96.237.15.189 (talk) 12:28, 2 August 2011 (UTC)

By 1851 there were 15 known asteroids, all but one with their own symbol. The symbols grew increasingly complex as the number of objects grew, and, as they had to be drawn by hand, astronomers found some of them difficult. This difficulty was addressed by Benjamin Apthorp Gould in 1851, who suggested numbering asteroids in their order of discovery, and placing this number in a circle as the symbol for the asteroid, such as ④ for the fourth asteroid, Vesta. This practice was soon coupled with the name itself into an official number-name designation, "④ Vesta", as the number of minor planets increased. By ca 1858, the circle had been simplified to parentheses, "(4)" and "(4) Vesta", which was easier to typeset. Other punctuation such as "4) Vesta" and "4, Vesta" was also used, but had more or less completely died out by 1949.

So. I put the explanation and history of the name in the article. 3 hours later, someone took it out. Brillant. I won't edit war. The next move is yours.-96.237.15.189 (talk) 23:53, 2 August 2011 (UTC)

The explanation is linked at the very top of the article, with the appearance of the designation, and I made the link a little "bigger" because it is a good question. The explanation is not distinct to Vesta, but is common to all minor planets, and so belongs in its own page, where it already was (and where it was copied from). It's silly to repeat the same thing over and over again in all pages for minor planets, or to single out Vesta for special treatment. Tbayboy (talk) 01:49, 3 August 2011 (UTC)

We single out Vesta for special treatment because it is special: it's in the news because of Dawn. A lot of people will come here who wouldn't normally visit asteroid articles, including a lot of kids, and they're not going to know what a "MPC designation" is, link or no link. We should say something. — kwami (talk) 09:14, 5 August 2011 (UTC)

I agree, this is no longer just any asteroid article. Vesta is in the news media a couple of times a week now, and will get periods of intense media coverage over the next year. It is therefore in line with Wikipedia's public education / encyclopedic mission to add more detailed explanations.

Writeonandon (talk) 12:56, 5 August 2011 (UTC)

"The explanation is not distinct to Vesta."

But, the explanation IS distinct to Vesta! Which is why it belongs here in perpetuity, regardless of whether other articles retain similiar material now or in the future. It is appropriate for both of these articles to have this material, but over time the other article may use entirely different examples.-96.237.15.189 (talk) 13:37, 8 August 2011 (UTC)

Is or Isn't Vesta the Number Two Largest Asteroid?

After seeing the original claim that Vesta is "the second largest asteroid" edited out in one spot, (but not all spots), along with an authoritative-looking note that Vesta is yet to be clearly determined to be either the 2nd or 3rd largest asteroid, I removed the (remaining) fragments also stating that is was "2nd largest", since this no longer appeared to be confirmed.

But my edits were then reverted, and now I am confused.

It looks like the "2nd place in size" status is being removed in some areas-- but left in place (and defended) in other areas, which is inconsistent.

Can we get a resolution on what to do here, so the article can be kept factually consistent?

(See also reference to "Ceres" in article opening that still mentions Vesta as being the "2nd largest asteroid").

Thanks,

Writeonandon (talk) 17:01, 5 August 2011 (UTC)

The situation is explained in the first paragraph of the Physical characteristics section. --JorisvS (talk) 17:21, 5 August 2011 (UTC)

Thanks for the link! OK I can see now, it's confirmed number 2 in mass, but not yet confirmed in size, due to density differences that may give Pallas the edge in total size, or volume.

Writeonandon (talk) 17:40, 5 August 2011 (UTC)

Dimensions

The currently stated dimensions of Vesta are from 14 years ago. Wouldn't the dimensions be known far more accurately now that Dawn is orbit around Vesta? --JorisvS (talk) 22:53, 7 August 2011 (UTC)

I added a note to the intro. We're basically waiting for the new data to be published.--agr (talk) 12:22, 8 August 2011 (UTC)

Southern crater

Does the huge impact basin near Vesta's south pole have a name? --JorisvS (talk) 15:22, 9 August 2011 (UTC)

Yes. It is called the "Huge Impact Basin". 107.29.180.162 (talk) 20:41, 9 August 2011 (UTC)

Not much of a name, is it? Think you could reference that? --JorisvS (talk) 20:53, 9 August 2011 (UTC)

Vesta's Hearth? Cheers, Greenodd (talk) 23:42, 9 August 2011 (UTC)

Maybe "Ouch!". — kwami (talk) 00:22, 10 August 2011 (UTC)

I like that one... the Ouch! Crater.:D Funny, but, seriously for one moment; so, can I conclude from the tone here that it still simply doesn't have one? --JorisvS (talk) 11:05, 10 August 2011 (UTC)

AFAIK, the only named Vestian feature is Olbers, and no-one knows what that is, because it's only visible in Hubble images. (Some large albedo feature that disappears when you get close up.) There are informal names like the 'snowman', and maybe the southern crater has one like that, but it's probably just 'southern crater'. I'm sure people are pondering what an appropriate name would be (Olbers would have been the obvious choice, like Herschel on Mimas), and for the central peak as well, but we don't even have the new mass measurements yet. — kwami (talk) 11:21, 10 August 2011 (UTC)

Yes. Any idea when we could expect elementary info like mass and dimensions to be published? --JorisvS (talk) 11:56, 10 August 2011 (UTC)

And why are we not getting any true-color shots? — kwami (talk) 11:30, 10 August 2011 (UTC)

Maybe because at NASA they think that true-color images are not really interesting? --JorisvS (talk) 11:56, 10 August 2011 (UTC)

From the rumours I've heard it's quite the opposite, but the Dawn team's data-release policy has come under some stick from enthusiasts for being relatively glacial. Do not expect anything more than a trickle of info. As for surface feature names, the team will eventually be required to present a surface map with suggested names to the IAU for example like was done with Lutetia [4]. ChiZeroOne (talk) 13:25, 10 August 2011 (UTC)

Here is 21 Lutetia's Wikilink in case anyone is interested.

69.171.160.5 (talk) 11:19, 13 August 2011 (UTC)