New clues to Ceres' bright spots and origins

December 9, 2015 by Elizabeth Landau
This representation of Ceres' Occator Crater in false colors shows differences in the surface composition. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Ceres reveals some of its well-kept secrets in two new studies in the journal Nature, thanks to data from NASA's Dawn spacecraft. They include highly anticipated insights about mysterious bright features found all over the dwarf planet's surface.

In one study, scientists identify this bright material as a kind of salt. The second study suggests the detection of ammonia-rich clays, raising questions about how Ceres formed.

About the Bright Spots

Ceres has more than 130 bright areas, and most of them are associated with impact craters. Study authors, led by Andreas Nathues at Max Planck Institute for Solar System Research, Göttingen, Germany, write that the bright material is consistent with a type of magnesium sulfate called hexahydrite. A different type of is familiar on Earth as Epsom salt.

Nathues and colleagues, using images from Dawn's framing camera, suggest that these salt-rich areas were left behind when water-ice sublimated in the past. Impacts from asteroids would have unearthed the mixture of ice and salt, they say.

"The global nature of Ceres' bright spots suggests that this world has a subsurface layer that contains briny water-ice," Nathues said.

A New Look at Occator

The surface of Ceres, whose average diameter is 584 miles (940 kilometers), is generally dark—similar in brightness to fresh asphalt—study authors wrote. The bright patches that pepper the surface represent a large range of brightness, with the brightest areas reflecting about 50 percent of sunlight shining on the area. But there has not been unambiguous detection of water ice on Ceres; higher-resolution data are needed to settle this question.

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Dwarf planet Ceres is shown in these false-color renderings, which highlight differences in surface materials. Images from NASA’s Dawn spacecraft were used to create a movie of Ceres rotating, followed by a flyover view of Occator Crater, home of Ceres’ brightest area.

The inner portion of a crater called Occator contains the brightest material on Ceres. Occator itself is 60 miles (90 kilometers) in diameter, and its central pit, covered by this bright material, measures about 6 miles (10 kilometers) wide and 0.3 miles (0.5 kilometers) deep. Dark streaks, possibly fractures, traverse the pit. Remnants of a central peak, which was up to 0.3 miles (0.5 kilometers) high, can also be seen.

With its sharp rim and walls, and abundant terraces and landslide deposits, Occator appears to be among the youngest features on Ceres. Dawn mission scientists estimate its age to be about 78 million years old.

Oxo Crater, which is about 6 miles (9 kilometers) in diameter, is the second-brightest feature on Ceres. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

Study authors write that some views of Occator appear to show a diffuse haze near the surface that fills the floor of the crater. This may be associated with observations of water vapor at Ceres by the Herschel space observatory that were reported in 2014. The haze seems to be present in views during noon, local time, and absent at dawn and dusk, study authors write. This suggests that the phenomenon resembles the activity at the surface of a comet, with lifting tiny particles of dust and residual ice. Future data and analysis may test this hypothesis and reveal clues about the process causing this activity.

"The Dawn science team is still discussing these results and analyzing data to better understand what is happening at Occator," said Chris Russell, principal investigator of the Dawn mission, based at the University of California, Los Angeles.

The Importance of Ammonia

In the second Nature study, members of the Dawn science team examined the composition of Ceres and found evidence for ammonia-rich clays. They used data from the visible and infrared mapping spectrometer, a device that looks at how various wavelengths of light are reflected by the surface, allowing minerals to be identified.

Ammonia ice by itself would evaporate on Ceres today, because the dwarf planet is too warm. However, ammonia molecules could be stable if present in combination with (i.e. chemically bonded to) other minerals.

An image of Occator Crater draped over a digital terrain model provides a 3-D-like perspective view of the impact structure. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

The presence of ammoniated compounds raises the possibility that Ceres did not originate in the main asteroid belt between Mars and Jupiter, where it currently resides, but instead might have formed in the outer solar system. Another idea is that Ceres formed close to its present position, incorporating materials that drifted in from the outer solar system – near the orbit of Neptune, where nitrogen ices are thermally stable.

"The presence of ammonia-bearing species suggests that Ceres is composed of material accreted in an environment where ammonia and nitrogen were abundant. Consequently, we think that this material originated in the outer cold solar system," said Maria Cristina De Sanctis, lead author of the study, based at the National Institute of Astrophysics, Rome.

In comparing the spectrum of reflected light from Ceres to meteorites, scientists found some similarities. Specifically, they focused on the spectra, or chemical fingerprints, of carbonaceous chondrites, a type of carbon-rich meteorite thought to be relevant analogues for the dwarf planet. But these are not good matches for all wavelengths that the instrument sampled, the team found. In particular, there were distinctive absorption bands, matching mixtures containing ammoniated minerals, associated with wavelengths that can't be observed from Earth-based telescopes.

The scientists note another difference is that these carbonaceous chondrites have bulk water contents of 15 to 20 percent, while Ceres' content is as much as 30 percent.

A group of scientists from NASA's Dawn mission suggests that when sunlight reaches Ceres' Occator Crater, a kind of thin haze of dust and evaporating water forms there. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

"Ceres may have retained more volatiles than these meteorites, or it could have accreted the water from volatile-rich material," De Sanctis said.

The study also shows that daytime surface temperatures on Ceres span from minus 136 degrees to minus 28 degrees Fahrenheit (180 to 240 Kelvin). The maximum temperatures were measured in the equatorial region. The temperatures at and near the equator are generally too high to support ice at the surface for a long time, study authors say, but data from Dawn's next orbit will reveal more details.

As of this week, Dawn has reached its final orbital altitude at Ceres, about 240 miles (385 kilometers) from the surface of the . In mid-December, Dawn will begin taking observations from this orbit, including images at a resolution of 120 feet (35 meters) per pixel, infrared, gamma ray and neutron spectra, and high-resolution gravity data.

Explore further: Ceres' bright spots seen in striking new detail

More information: Nature, nature.com/articles/doi:10.1038/nature15754
Nature, nature.com/articles/doi:10.1038/nature16172

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Osiris1
1.9 / 5 (18) Dec 09, 2015
A million lies in the big city, and here is another one! Governments just can NOT get it through their collective cretin heads that all the public can NOT be fooled ALL the time. Even as we read the above pack of funny mushroom/lsd visions from government agents, plans are being hatched to go there....quietly.... or send that craft ever closer, even sacrificing DAWN if necessary to see JUST WHO has set up shop in our system. Of course if we lose DAWN in the process, there are literally millions of excuses as to 'how'.
Osiris1
1.5 / 5 (16) Dec 09, 2015
Or maybe I will buy a bottle of ammonia and use it to light my house at nite. Just add a little of the right kind of 'salt' to make it shine brighter. Heyyyy NASA, How much to get a hundred watts worth of lumens out of it? Why did you not tell us how to get light energy from literally nothing before? Hey? Hey? Awwww! dat's classssified, just like the truth about those spots.
matt_s
4.2 / 5 (13) Dec 09, 2015
Hahaahahahah is Osiris actually serious?
baudrunner
2 / 5 (4) Dec 09, 2015
This raises flags concerning Saturn's moon Titan. Its stratosphere is 98.4% nitrogen with methane and hydrogen making up the rest. 50% of Titan's mass appears to be water ices and ammonia hydrates. It is tempting to establish some kind of link, in order to put the historical dynamics of the evolution of our solar system into some kind of temporal framework.

Ceres is dirty, from the looks of things, and so the brightest spots represent the most recent meteoric collisions. What is more interesting now than Ceres' bright spots is, just what is the composition of that upper layer? Is it cosmic dust, or some kind space-originating black mold?
Whydening Gyre
4.3 / 5 (6) Dec 09, 2015
Is it cosmic dust, or some kind space-originating black mold?

Amines...;-)
Protoplasmix
4.4 / 5 (7) Dec 09, 2015
Hahaahahahah is Osiris actually serious?
Yes, seriously trolling.
NIPSZX
2.3 / 5 (6) Dec 09, 2015
The pics and videos are all representations. This is unfortunate and leads to a bad reading.
Frosted Flake
1.8 / 5 (10) Dec 09, 2015
How many times have we seen multiple rows of craters laid in a straight parallel pattern on a tiny planet or large asteroid?

This seems 'artificial' to me. Meteors do not land in neat, parallel rows. I wonder if NASA will ever acknowledge these apparently very common, totally unexplained astrophysical (you gotta suppose) features.
jsdarkdestruction
4.5 / 5 (8) Dec 09, 2015
https://en.m.wiki...er_chain
Quite a few flake.
FredJose
2 / 5 (8) Dec 10, 2015
Dawn mission scientists estimate its age to be about 78 million years old.

It would be highly illuminating to know just how they came to this estimate - they are so far away from it and nobody has seen Ceres forming or even the crater forming so just how do they know that it's not 1503, 150000 or 14543000 years old?
Vietvet
4 / 5 (12) Dec 10, 2015
Extended Data Figure 3: Crater counting area, superposed impact craters and model age.

http://www.nature...SF3.html

@Freddy

If you really wanted an answer to your question you could have done what I did, a Google search that took less than a minute.
my2cts
4 / 5 (8) Dec 10, 2015
Dawn mission scientists estimate its age to be about 78 million years old.

It would be highly illuminating to know just how they came to this estimate - they are so far away from it and nobody has seen Ceres forming or even the crater forming so just how do they know that it's not 1503, 150000 or 14543000 years old?

Well FredJ, when was Ceres "created" in your belief system? Let's have a laugh.
katesisco
2.6 / 5 (5) Dec 10, 2015
I wonder if our own history may help here? We humans were nearly extincted thousands of years ago, perhaps 50,000m or so. Down to a thousand maybe. What if these holdouts were in a protected low area sheltered by high walls--a crater. Like Rongoro Rongoro in Kenya.
The high crater walls protected the area from being swept with high winds, held exuded moisture inside, allowing for prey and predators to survive. Makes sense.

Note also that the 80 my ago creation of the crater may be in a result of solar activity that affects all planets.
antialias_physorg
4.4 / 5 (7) Dec 10, 2015
How many times have we seen multiple rows of craters laid in a straight parallel

All the time? You can see them on Earth, on the Moon, and basically on any object in space where you can see craters.
As soon as something rotates relative to an incoming, fractured object (and there's plenty of those around) you get these crater patterns.

It's the same effect you can observe on your car. Note how, if you drive through mud, your car is spattered in streaks? Now, if you want to argue that mud is intelligent then you'll probably have to find another place to post that...
EnsignFlandry
3.7 / 5 (6) Dec 10, 2015
A million lies in the big city, and here is another one! Governments just can NOT get it through their collective cretin heads that all the public can NOT be fooled ALL the time. Even as we read the above pack of funny mushroom/lsd visions from government agents, plans are being hatched to go there....quietly.... or send that craft ever closer, even sacrificing DAWN if necessary to see JUST WHO has set up shop in our system. Of course if we lose DAWN in the process, there are literally millions of excuses as to 'how'.


But you are so intelligent and knowledgeable that you've penetrated the government's space secrets? The Edward Snowden of Space.
FineStructureConstant
3 / 5 (6) Dec 10, 2015
Hahaahahahah is Osiris actually serious?
Well, yes: but only because he's (a) obsessed with conspiracy theories, (b) fanatically anti-government, and (c) he simply doesn't grasp the ideas of relative brightness, of contrast, or of camera sensitivities.

He's a first-class moron, end of.
mreda14
2.3 / 5 (3) Dec 11, 2015
I wonder what made Beagle 2 the British landing spacecraft a ghost spacecraft laying dead on the desert of Mars.
Beagle 2 is a British landing spacecraft that formed part of the European Space Agency's 2003 Mars Express mission. Beagle 2 is named after HMS Beagle.

The spacecraft was successfully deployed from the Mars Express on 19 December 2003 and was scheduled to land on the surface of Mars on 25 December; however, no contact was received at the expected time of landing on Mars, with the ESA declaring the mission lost in February 2004, after numerous attempts to contact the spacecraft were made
maks06
2.3 / 5 (3) Dec 12, 2015
Source for such bright spots is usual connected with processes when Calcium carbonate react with water.
Osiris1
1.7 / 5 (6) Dec 13, 2015
What a fine little pack of backbiters we have become, so that any deviation from now....scientific correctness (SC ??!) rates knee jerk reactions from jerks who choose not to think when presented with fairy tales. Glowing takes energy. This place is so far out that little solar reaches it. And every government 'explanation' gets leapt upon like a long lost gospel. Lots of phenomena in our universe appear not to make sense. Some have given up and let the trolls hold forth.....money talks and b.s. walks. Who pays YOUR salary? More than one can wield the digital 'fickle finger of fate' Daresay no airline pilots or military aviators on here with long experience. Too many such have seen the truth but know the futility of tempting fate with their careers at the hands of puppets of scared old men, so they stay quiet. Besides, most of those that know are not small minds that resort to personal attacks when faced with the lack of logic and knowledge to understand the truth.
my2cts
4.3 / 5 (6) Dec 13, 2015
What a fine little pack of backbiters we have
Note that "deviation from scientific correctness" just means "proven wrong".
Your statements are not in that category but in the category "wronger than wrong".
https://en.wikipe...an_wrong
AGreatWhopper
2.1 / 5 (7) Dec 13, 2015
Frosted Flake1.6 /5 (7) Dec 09, 2015
This seems 'artificial' to me. Meteors do not land in neat, parallel rows.


It would be nice to have a syntax checker that popped up a message that says, "Conspiracy Cognitive Dysfunction" when those that suffer from it do the SAME 10 or so things every topic. Hard to find any of their discussions that don't start with "just think about it; that doesn't seem right"- despite the fact they have no basis for evaluating that- then state something without data that is just wrong. Cornflake has an innate sense of what's the norm in nature, makes an unsubstantiated declaration, and we're off to the races!

Why are you types here? That's the antithesis of science. Hold your Special Olympics on another site. Why would you do it on a science site that represents polar opposite thinkging???
AGreatWhopper
2 / 5 (8) Dec 13, 2015
Osiris11 / 5 (2) 13 hours ago
What a fine little pack of backbiters we have become, so that any deviation from now.


Go fuck yourself in the asshole until you bleed to death, you fucking vermin.

katesisco2.3 /5 (3) Dec 10, 2015
I wonder if our own history may help here? We humans were nearly extincted


Extincted. That's natures way of telling you, "You're a moron, STFU!"
Captain Stumpy
5 / 5 (4) Dec 13, 2015
Why are you types here? That's the antithesis of science. ...Why would you do it on a science site that represents polar opposite thinkging???
@Whopper
for the same reason the Jehova's witnesses come door to door

to share their religion and seek like minded converts
my2cts
5 / 5 (2) Dec 14, 2015
Dawn mission scientists estimate its age to be about 78 million years old.

It would be highly illuminating to know just how they came to this estimate - they are so far away from it and nobody has seen Ceres forming or even the crater forming so just how do they know that it's not 1503, 150000 or 14543000 years old?

You say this because you know nothing.
Your brains are full of it.
Get an education.
PhotonX
5 / 5 (4) Dec 14, 2015
How many times have we seen multiple rows of craters laid in a straight parallel pattern on a tiny planet or large asteroid?

This seems 'artificial' to me. Meteors do not land in neat, parallel rows. I wonder if NASA will ever acknowledge these apparently very common, totally unexplained astrophysical (you gotta suppose) features.
What an absurd assertion--there's nothing "totally unexplained" about it--we know exactly how these features are formed. It's especially baffling given that we have actually directly observed exactly such a natural phenomenon, when Comet Shoemaker-Levy broke apart in linear fashion before impacting Jupiter in exactly the manner you find suspicious. You ignore the direct observational evidence, both in actual orbits as well as preserve many times in the fossil surface records of many objects, and invoke magical thinking when the facts don't match up with your preconceptions.
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