The interior of asteroid Vesta

Jan 06, 2011
On its southern side the asteroid Vesta shows a huge crater. This picture shows the asteroid in an image taken by the Hubble Space Telescope (top, left), as a reconstruction based on theoretical calculations (top, right), and as a topological map (bottom). Credit: Ben Zellner (Georgia Southern University) / Peter Thomas (Cornell University) / NASA

(PhysOrg.com) -- Researchers from the University of North Dakota and from the Max Planck Institute for Solar System Research in Germany have discovered a new kind of asteroid using NASA’s Infrared Telescope Facility on Mauna Kea, Hawaii. The mineralogical composition of 1999 TA10 suggests that unlike many other asteroids it did not originate from the outer rocky crust of its parent asteroid Vesta, but from deeper layers.

Until now, no asteroid with this composition was known. With the help of this new discovery it is now possible to determine the thickness of Vesta’s crust and study its internal structure. In this summer Vesta will be the first destination of NASA's mission DAWN. In addition, the body with a diameter of approximately 525 kilometers is believed to be the only remaining protoplanet from the early phase of our . (Icarus, in press, published online on December 5th, 2010)

The asteroid Vesta is unique: Unlike all other minor planets, that orbit the Sun within the main belt between the orbits of Mars and Jupiter, Vesta has a differentiated inner structure: A crust of cooled lava covers a rocky mantle and a core made of iron and nickel - quite similar to the terrestrial planets Mercury, Venus, Earth, and Mars. Scientists therefore believe this onion-like built asteroid to be a protoplanet, a relict from an early phase of planet formation more than four and half billion years ago. All other protoplanets either accumulated to form planets or broke apart due to violent collisions.

Vesta seems to have witnessed a huge impact, as can be seen from a large crater on its southern hemisphere. The so-called Vestoids - a group of asteroids with a composition similar to that of Vesta - were most probably created due to this impact. Since some meteorites that were found on Earth consist of similar rock as does Vesta’s mantle, scientists believe that this collision also hurled material from deep within the asteroid into space. But till now there was no source in the form of near-Earth Vestoids for these meteorites with Vesta’s mantle composition.

Near-Earth asteroid 1999 AT10 fills this gap. Using the IRTF, the scientists were now able to analyze the infrared-radiation that 1999 AT10 reflected into space and compared its characteristic spectral fingerprints with those of Vesta. Apart from calcium-rich wollastonite, the measurements mainly point to iron-rich ferrosillite. ‘‘These materials can be found in Vesta’s mantle and crust," explains Dr. Andreas Nathues from MPS. ‘‘However, the ratio is decisive." In the case of 1999 AT10 the concentration of iron is clearly lower than in any known Vestoids. "This all points to 1999 TA10 having originated from the interior of Vesta," says Nathues.

The newly discovered body now allows important inferences about its parent asteroid. Models of Vesta's surface based on observations made by the Hubble Space Telescope render a depth of the South Pole crater of ~25 kilometers at the most. The new discovery now suggests that this would be the maximum possible thickness of the outer crust.

In order to reconstruct the processes that led to the formation of planets more than 4.5 billion years ago, scientists need to determine the thickness of Vesta's layers as precisely as possible. Only this makes it possible to calculate from which material mixture the protoplanet was made - and thus which materials were present when the solar system formed and in what ratio.

The scientists now hope for more information about Vesta's structure from NASA's mission Dawn. In August 2011, the probe that has been traveling through space since 2007, will rendezvous with and orbit the for a year. On board Dawn there are two cameras that were designed and built under the leadership of the Max Planck Institute for Solar System Research in cooperation with the German Space Agency (DLR) and the Institut für Datentechnik und Kommunikationsnetze of the Technical University of Braunschweig.

Explore further: Image: Crescent Mimas

More information: Vishnu Reddy, et al. "First fragment of Asteroid 4 Vesta’s mantle detected." Icarus, in press, published online on December 5th, 2010.

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User comments : 13

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Quantum_Conundrum
1.3 / 5 (16) Jan 06, 2011
In all likelihood, when the space craft gets there it will totally overturn everything they think they know about Vesta, and all of this speculation will have been a complete waste of time.
Shootist
3.7 / 5 (12) Jan 06, 2011
In all likelihood, when the space craft gets there it will totally overturn everything they think they know about Vesta, and all of this speculation will have been a complete waste of time.


Your theme?

Wonderful World
Don't know much about history,
don't know much biology.
Don't know much about a science book,

Science comes from observation. Good observations make good science. Even if the results are unexpected.

Spectrographic observations are rarely wrong. Unlike people, photons don't lie.
cbellh47
not rated yet Jan 06, 2011
You mention two different asteroids 1999 TA10 and 1999 AT10. Something appears to be in error.
yyz
5 / 5 (1) Jan 06, 2011
@cbellh47, Yeah, the original PR linked to this story has the same error. From the abstract, the body is noted as "near-Earth asteroid (237442) 1999 TA10".
Terrible_Bohr
5 / 5 (3) Jan 06, 2011
In all likelihood, when the space craft gets there it will totally overturn everything they think they know about Vesta, and all of this speculation will have been a complete waste of time.


Just like your speculation?
Jonseer
2.3 / 5 (3) Jan 06, 2011
Science comes from observation. Good observations make good science. Even if the results are unexpected.

Spectrographic observations are rarely wrong. Unlike people, photons don't lie.


The problem with what you say is pretty obvious.

The asteroid belt was long ago dismissed as just leftover debris from the formation of the solar system and thus not received much observational attention from our Astronomers. We seem to know more about what the surface of Pluto looks like than we do of Ceres or Vesta.

So there is little in terms of results and conclusions re: Vesta or any of the largest Asteroids.

Spectrographic observations may never be wrong, but the INTERPRETATIONS can be very wrong.

Speculation though is never a waste of time.

It's the fuel for the desire to explore.

Had human beings never speculated about what was over the next hill, we'd all be still living in the same valley in which modern humans evolved. The few of us that would be alive that is.
PieRSquare
5 / 5 (4) Jan 06, 2011
In all likelihood, when the space craft gets there it will totally overturn everything they think they know about Vesta, and all of this speculation will have been a complete waste of time.


I can hardly wait until the Dawn results come in and you call that a waste of time too...

Couldn't you content yourself with waiting in your fear bunker until the rapture comes instead of cluttering up the forums with your grouchy drivel?
nevermark
5 / 5 (4) Jan 06, 2011
In all likelihood, when the space craft gets there it will totally overturn everything they think they know about Vesta, and all of this speculation will have been a complete waste of time.


Do you really not know the difference between "speculation" and "waste of time" and the science explained in this article? Ouch.

Yes, every interpretation of initial data could prove to be wrong. That is a generic truth to any study, it isn't news to scientists, and it has no special relevance for this study. Spectrographic data is rich in information and less likely than many other kinds of data to be misleading.

I don't understand the need to put down research for no specific reason, which seems to happen a lot on this site. I suppose some people are insecure about science and it makes them feel better by expressing vague cynicism and imagining they are adding something to the conversation.
Quantum_Conundrum
1 / 5 (1) Jan 07, 2011
Couldn't you content yourself with waiting in your fear bunker until the rapture comes instead of cluttering up the forums with your grouchy drivel?


The "Rapture" is a false doctrine and has no basis in scripture. In fact, it directly contradicts many things discussed in the Bible.

A full exegesis takes much longer than the 1000 characters of this post, but you can find some simple proofs by just reading the book of Revelation, and noticing that believers are persecuted throughout the entire ordeal. If all the believers had supposedly disappeared in a secret rapture before this ever happens, then there wouldn't be any believers to be persecuted, particularly since the text says 4 different times that none of the unbelievers are going to repent.

In short, there is no "secret rapture". There is only the "second coming" which is described in detail at the end of the book of Revelation and elsewhere in the Bible, and happens only after the "man of sin" is revealed.
Shootist
2.3 / 5 (3) Jan 07, 2011
The asteroid belt was long ago dismissed as just leftover debris from the formation of the solar system and thus not received much observational attention from our Astronomers. We seem to know more about what the surface of Pluto looks like than we do of Ceres or Vesta.


You are incorrect. The difficulty lies in gathering enough photons, from these small objects, to make useful observations., not from some "lack" of interest on the part of astronomers.
GSwift7
3 / 5 (4) Jan 07, 2011
I think it's interesting to read science fiction from different time periods and see the changes in the science they use to build the fiction. There's a series by Ben Bova called the Asteroid Wars, written around 2000, that talks quite a bit about what they knew at the time about the main belt. It's a good read and I thought the audio version was great as well. Bova tends to write fairly hard scifi, so his books make an intersting snapshot of the science of that decade. Another one I enjoyed was the Mars trillogy by Kin Stanley Robinson from the early 90's. It's really great to see all the things that were speculations at the time the books were written which later proved to be true or false.
dtxx
5 / 5 (3) Jan 07, 2011
... but you can find some simple proofs by just reading the book of Revelation,


I think most here will strongly disagree with that statement and all of its assumptions.
gwrede
3 / 5 (4) Jan 10, 2011
Shootist wrote:
You are incorrect. The difficulty lies in gathering enough photons, from these small objects, to make useful observations., not from some "lack" of interest on the part of astronomers.
You are incorrect yourself. We gather much more photons from Vesta &co than from Pluto. So, it actually is about interest.

QC wrote:
but you can find some simple proofs by just reading the book of Revelation
This shows that QC does not comprehend the meaning of the word proof. Therefore he will not accumulate knowledge and understanding from reading scientific literature, or this site, either. Doing that is merely like building a house directly on the lawn, instead of first erecting a proper foundation for it.