After some searching, I was able to find an interview with Christopher Russell on a dubious website (though the interview itself seems fine enough) saying pretty much the same thing (about an embargo):








(source)

I have seen nothing about this in other channels, though.

I'm expecting to se a clutser of impact craters somewhat modified by subsequent sublimation (including hazes).

That sounds like a pretty extreme conclusion from very limited data.

Btw, Russell is quoted in that interview as saying "And this white stuff might have an albedo of 50 percent." I think that's the first mention I've heard of an albedo value.

If this embargo is really happening, can we even be sure that we'll see the HAMO images of Occator before the LAMO images of it?

Thanks for that link Habakuz. That interview had several interesting points.

Somebody linked me to that on Twitter, and the interview (and the explanation) seem perfectly plausible, but it seriously bugs me that the only source for it is a website that, well, looks like that, and whose content is 80% UFO nuttery.

I could care less. It's their science and their papers-- after all, their career track is governed by the "publish or perish" rules. If they feel it necessary to embargo THE photo of the year til the paper gets out and oo'ed & ah'ed, that's fine. In the Big Picture, it'll just be another pretty picture. In the meantime there are a multitude of puzzle pieces coming out with each HAMO image. Nothing spectacular, but individual puzzle pieces generally aren't-- it's the sum that is important.

Anyways, with the Occator Spots, I think they are hydrothermal features-- various salts entrained in the escaping vapors and left behind as the gases expand and dissipate. The big surprise may be which salts in what gases.

--Bill





YAY TEAM-- we got HAMOs of the Occator Faculae. And first thing in the AM. Good show.

-b

Speak of the devil:

https://twitter.com/NASA_Dawn/status/641420466029113344

Regardless of the website source, the interview seems better than "perfectly plausible" in my estimation.
The questions were tough and well-informed, and the answers were candid and not at all evasive.

Ms. Howe gives a pretty good model of how to interview a researcher about delicate or breaking news, but of course it is not a substitute for the pictures themselves. I hope we will see them pretty soon.

im glad it was just a rumor. seemed to have a hint of credibilitg.

nice to get a name drop

So was this an actual misstep in communication among the team or is the interview bunk? It's a fairly well written work of fiction if that is the case. Strange slip-up otherwise if it is true...

If I'm understanding their twitter correctly, there was a paper submitted and embargo was a possibility but they've determined it doesn't extend to the pictures. Which probably means the interview was real.

In my view there's a lot of excessive caution with regards to Nature and Science embargo policies, but on the other hand I can't blame scientists for being skittish. I've often observed that the best way to be certain about exactly what the embargo policy means is for a scientist to make a public statement that an embargo prohibits them from sharing information -- then Nature or Science "clarifies" the policy and says it's okay to share

Photojournal was uploading pictures of Occator when suddenly, right after I had opened the nadir view, it disappeared...

Just want to confirm with everyone that it would be ok to repost it here. It looks very intriguing indeed.

Apparently it's still there, the thumbnails is just incorrect. Link

Occator enlarged.

Phil

Click to view attachment

The brighter areas do look to be associated with the fault-like features to me. Also (only to my very ameatur eyes) I see nothing that looks like a conventional crater-and-ray. The central peak looks like it's, well, snow capped (salt capped possibly?).

Still looking weird as heck. Lots of fissures in Occator, too.

The fact that it is a composite image of different exposure times make it somewhat harder to interpret.

What's this; topography or dark material?

Click to view attachment

And these dark patterns on the rim? Processing artefacts or real?

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I'm not thinking that the central feature is primarily a raised feature. Be it an impact crater or a caldera, the main bright area is nicely tucked into a circular feature, isn't it? But the very straight cracks, especially the one going straight up in your detail, Phil, are not very deformed by the circular feature. So, the cracks seem to have formed after the circular feature. And while the lighting doesn't give a lot of clues, I get the impression of there being a building central mound within the larger crater- or caldera-like depression.

I also think I may see what Russell, et al, have been discussing -- if you look at the very end of the crack that, again in this detail, runs straight up from the main bright area, there are a couple of very subtle dark streaks in the little bit of brightening around that end of the crack. While I can't, obviously, say this is happening for certain, these streaks resemble shadows cast on the surface from the densest portion of a fountain of material coming out of the top end of that crack. Recall that Enceladus is pumping out a lot of material along its tiger stripe cracks, and yet the only real visible clue it's happening when looking straight down into the cracks from Cassini has been such subtle shadowing.

The area of the secondary bright area, at the 2:00 position from the main bright area in the detail above, is sitting within an irregular boundary of a low, continuous scarp that makes something of a sausage- or cigar-shaped enclosure. Could represent cooling of a once-liquid body, akin to a lava lake, or could even represent a small, irregular caldera-like formation grown from escaping material from a crack that may have once run underneath it. If so, that crack appears to have been completely buried by now.

Finally, look for obvious impact craters. In the entire detail image, I see two very small ones. Even if this is a fairly new crater (and I dispute that, based on the amount of mass wasting I see in the walls), I would expect to see more small craters on its floor. The conclusion is that the floor, in the general vicinity of the bright areas, has been resurfaced by processes far more recent that the creation of Occator.

Now, let's get some LAMO images...

-the other Doug

The lack of impact craters inside Occator is a fair point; but there are not many impact craters outside it, either (i.e. where the ejecta blanket should be), which is consistent with Occator being a relatively young impact crater.

Side view from next orbits will help assessing the relief before LAMO.
Do I see a trianguler "hole" at 9 O'clock?

Processed enlargement of the Occator image.


(click to enlarge)

I would really like to see this composite separated. It played havoc with the overall quality. I'm not positive but I think the south edge of the central spot is even showing a misalignment, possibly due to a change in orientation of the spacecraft.

Click to view attachment

At the south of the crater is some interesting fracturing that seems to spread from a common point. Contrasting with the slumps on the edges of this and other craters, it appears that at the north, there is a slump or flow outward toward the crater wall as if something had flowed from the center out. This could be a lighting illusion though.

A while back I also made a blinking GIF comparing an unprocessed crop from SO16 with a processed enlargement which still seems to have relevant features.

Click to view attachment

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I did a comparison between the SO 16 processed image and the current HAMO view and if it is not simply artifacts, there's a (limited) possibility that we could see some active movement in this area. Probably just artifacts though. I'm going to hope it isn't though.

Click to view attachment

Most notably, the dark patch that seems to disappear from the brightest area.

think we can rule.out abandoned mining colony. tho it made for some great reading.

i think the triangle at 9 oclock is an artifact same tging you see at 12 and on crater walls. what im seeing is totally bizzare..why cant it be ice? it looks like ice. it also looks like venting at 2 oclockor paradoliea

From the interview linked in post 101:
"I have heard no report back from the team on any signature of ice from the VIR spectrometer, so I'm going to say it must be some sort of salt."

It looks similarly to some Mercury's craters.

Initially, a comparison between an early Survey Orbit image of the "Occator Spot" and this first public HAMO image of this feature.

https://univ.smugmug.com/Dawn-Mission/Ceres...PIA889_HAMO.png

Otherwise, I am somewhat giddy from what I'm seeing here.

--Bill

Looks like at the 9 o'clock position that the flow from the central white spot, hit a rise and was diverted north.

But overall, to me Occator is starting to look less like an impact crater and more like a series of collapsed calderas, with the white spots the latest stage of rebuilding.

North of the central white spot, there is what looks like a lava flow front, with bands following the edge of the front.

There's a clear halo to the north of the CWS, ending a little north of the straight crack, but also extending to the right, up to where the small mound is located on the surface. The edge there could be the end of a lava flow, since it looks higher than the area further east. On the western side, it's hard to tell from the JPG but it looks like the flows have bypassed back and forth past some higher ridges, with some curves just the left of the bad spot on the imager (or those could be ringing from excessive edge enhancement, it's difficult to tell here). NW at 11 o'clock is what looks like an old flow, slightly lighter than the surroundings, extending past the halfway point to the rim.

Many of the smaller white spots away from the CWS and the NE quadrant appear on the side of a crack - maybe the cracks were tilted, with fountains aiming mostly down hill.

My bet is on the white material being salty slag left over after the cryovolcanic ice has sublimated away. As the activity on Ceres ramped down, this happened to be the last gasps, with Occator being a volcano that once it collapsed, continued to have some activity, but never enough to get past its outer collapsed caldera. Each active cycle laid down a little less new salt, with the older salts darkening over time.

I wonder if the other craters with central pits once had Occator-like events/processes but have since faded.

Click to view attachment

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And how does the visually bright Facular material change with time if not renewed? Could it darken and fade to match the tone of the surface, or even darken and diffuse to look like a Macula? I have a feeling (hope?) that it will have a distinctive spectral signature and stand out in VIR imagery

--Bill

Just my own high level conjectures at this point: while the light material is clearly draping, we can classify draping as either new/durable or older/decayed. The draping features on several of Jupiter's moons represent new/durable and possibly ongoing accumulation. Here, if the draping is new, we'd have to explain its absence from many areas within the draped region. I'd expect salts, regardless of their type, to be a durable material whose draping would persist and perhaps discolor evenly, but not dissipate. So far, this is looking like an older event comprised of a material that has had time to either dissipate, become preferentially altered, or be partially covered by very localized dark draping events (that is, the dark circles may not be pits but spots). A final possibility is that the buildup is preferential, not sticking to some surfaces. The terrace-like nature of the big spot may be such a build-up. I don't see any mechanisms for particulate fallout to deposit preferentially. So I'm going with an older, volatile, decayed surface not involving salts, with a backup option of a newer surface (ice or salt) altered by "smokers" or sublimation. What else could explain the apparently differentiated draping?

Edit: I think Bill and I were experiencing similar thoughts about appearances while writing our posts!

Hi all,
an anaglyph obtained with the last image and the latest from survey and a detail of the last photo.





It seems that a part of the main "Bright Spot" has slipped to the dirty-white area, upper right of the image, leaving two tracks.

It would seem reasonable to me that it has happened in at least one other location on Ceres, even if time has since made it difficult to observe. I still think Ceres has been a very cryovolcanically active body in the past and very possibly still now. The closer we get to the central area in Occator, the more similarities I see with other larger craters with the exposed white material, namely Haulani. I think Haulani represents a much older and possibly larger version of the events that are just beginning at Occator.

Updated imaging map:


(click to enlarge)

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Also, here is an attempt to pull out everything possible from the central and brightest blob.

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Looks like there could be a fissure running through the center. Overall, looks like a mini version of the larger pit surrounding it.

It also looks somewhat similar to an aerial view of Old Faithful (minus the public reception area).

If any fluids in the interior are able to collect in pockets (in the manner of petroleum and natural gas reservoirs on Earth), and not dissipate or freeze out, they could eventually make it to the surface as an eruption. It doesn't matter how long the planetary body has been otherwise 'geologically inactive'. This could be the case with gases in the Moon and Mercury as well as liquids and/or gases in Ceres. In any case, though, a conduit to the surface needs to be opened by some direct or indirect process(es) for an eruption to occur. The faults and fractures associated with an impact rebound could serve such a purpose.

played around with photoshop..bring out more details. zoomed in and im not sure if it is an actual feature or not. Some sort of dome appears be rising out of the center of the bright spots. have a look

http://m.imgur.com/sQP6wcA


it could also be an illusion..considering this is actually two pictures overlayed from nasa. guess we will have to wait till LAMO.

A central, eruptive mound is how the main bright spot appears to me, as well. And while there are a number of bright spots around Ceres, this is the only feature that has the appearance of being eruptive.

-the other Doug

Maybe I missed it, but are there any theories as to why grabens seem to be so common in these craters, and with directions that seem to lack any apparent regard to their location in the crater? I noticed that they seem in some cases to run straight across white spots, indicating that they're younger than the white spots (including if, as hendric suggests, that they're salt deposits left behind from sublimated saltwater ice - then time for all of the volatiles to sublime). This would seem to indicate that they're not all formed at the same time as whatever causes the saltwater to surface (if that is indeed what's actually happening here). The tectonic activity is proportionally young.

As for saltwater oceans, frozen or not... Enceladus seems to be producing an ultrabasic soda ocean with relatively little heat input via serpentinization of rocks with its core. If the spectra come back with significant Na2CO3 then we may be looking at something like that here. Which would be really interesting, as serpentinization also gives off H2.

I am surprised that in the interview with Christopher Russel, Russel seems to link Haze with an atmosphere -necessary - to levitate or maintain some material aloft. The LDEX instrument on LADEE was designed and operated around the moon in 2014 to "gauge the relative contributions of the two competing dust sources: (1) ejecta production due to the continual bombardment of the Moon by interplanetary micrometeoroids, and (2) lofting of small grains from the lunar surface due to plasma-induced near-surface electric fields"

paper here
description here

If the white material that deposited in occator is very fine (0.1 micron for the moon), the same process could take place and show variability along cerean day and eventually lead to time dependent haze...

I've just been looking at Emily's anaglyphs and thought I could see a hint of a central protuberance in Haulani crater. It will be interesting to compare it with the Occator feature when a similar anaglyph of central Occator becomes possible. http://www.planetary.org/blogs/emily-lakda...ge-bonanza.html

Haha, hadn't seen that on her blog yet. Emily, that map took multiple aggravating hours I'm sure! Great to stereo images as well.

I did a Google Maps grab of the Old Faithful area in Yellowstone before seeing that Charles had posted a more close-up view of the same area. I'll try to provide a side-by-side comparison.

Ceres has 3% of Earth's surface gravity, so a projectile would travel 1/sqrt(3%) = 6 times farther across the surface.

So, here are the Occator bright spots next to geyser deposits at Yellowstone on Earth, with the Earth imagery magnified six times to illustrate how they might project under Ceres gravity. This, however, also scales up the distance between vents, which has no bearing on anything.

Occator ~ Yellowstone on Ceres?

Why sqrt?

And thanks to you for your maps, you saved me many aggravating hours staring at craters to try to match them with the base map.

Processed enlargement of HAMO 12.


(click to enlarge)

Seems consistent to past images we've seen of this area.

Imaging location map:


(click to enlarge)

HAMO12 is located to the southwest of Toharu in the southeastern region. I will probably adopt a lot of the conventions in your map Emily and further refine positions over time.

A bit early for theories, but we sure got plenty of ideas!
Some time back I made a post where I speculated it would turn out to be be salts in most of the bright areas. But the kept the door open for Occator, thinking it might perhaps be one exception.
Now since we see the graben run trough some parts of the white area, (thanks to eliBonora for those processed images) I'd say this rather strengthen the case for salts.
Ice would have to be relatively new, more recently exposed - geologically speaking, exposed ice will sublimate since it is exposed to near vacuum.
Now with those graben the date is pushed far back for the formation of Occator, and since I don't have any professional reputation to taint, - I now feel quite biased to think the bright Occator is made of salts after all.
This does not exclude the idea that the bright features once were formed by some eruption or geyser-like event - but it seem to have happened further back in time.

The distance a projectile will travel horizontally is proportional to the square root of the acceleration due to gravity. I'll leave the equations out of my answer and you can trust me or work it out for the fun of it.

ERRATUM: The distance a projectile will travel horizontally is inversely proportional to the acceleration due to gravity. The distance a ballistic projectile will travel on Ceres is about 35 times that of a similar projectile on Earth.

If an horizontally-moving object needs to fall 1 meter to hit the ground and is in a 1 m/s^2 gravity well, it hits the ground 1 second later.
If the same object needs to fall 1 meter and it's in a 4 m/s^2 gravity well, it hits the ground 0.5 seconds later (4m/s^2 * (0.5s)^2 = 1m)
Quadruple the gravity, halve the fall time and thus the travel distance. Cut gravity in a quarter, double the fall time and travel distance.
Gravity squared is proportional to travel distance. Travel distance is proportional to gravity squared.
Ceres gravity is 3% that of Earth's. Travel distance on Ceres is proportional to 1/(3% earth gravity)^2, or about 1100 times as far.
Right?

t = sqrt(2d/a) = sqrt(2) = 1.4142... seconds


t = sqrt(2d/a) = sqrt(2/4) = 0.7071... seconds


The rest of the argument is correct.

Could be like the pits on mercury. Mass wasting of volatile material.
Big question is, what counts as "volatile" gone in a day, a year, a century, an eon?
Second question, is that wasting triggered by the heat of the impact,
by removal of an insulating dust layer, or both?

I'm thinking of recent Brown U. research that some weird lunar patters "swirls"
result from a transient atmosphere as a result of a comet and it's coma hitting the moon.




Not sure why, but I don't think just saltwater is likely, perhaps something more hygroscopic, some sort of silicate mud? \
That could create some neat formations, a mix of mid ocean ridge "black smokers", mono lake "tufa towers" or frozen geysers.

i few different views of
http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA19889


the height is exaggerated

Processed enlargement of HAMO 14.



Not sure why they have skipped HAMO 13.

More white material in this image. This is also from an area with a high number of linear streaks. One in particular appears rather dark in comparison to the others, noted in the image below.

Click to view attachment

This could just be an effect from lighting but I haven't seen anything similar to it elsewhere on Ceres yet. It also seems to be visible in SO37 (PIA19610).



Imaging location map
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This one took a while to find. It was an area only imaged twice and once was near the edge in a limb view.