. 24/7 Space News .
Research Offers Clues About the Timing of Jupiter's Formation
by Staff Writers
Providence RI (SPX) Dec 13, 2016

New research finds that the solar system's largest planet was likely near its current size--318 times the mass of Earth--by about 5 million years after the first solids in the solar system formed. Image courtesy NASA/JPL-Caltech/Space Science Institute. For a larger version of this image please go here.

A peculiar class of meteorites has offered scientists new clues about when the planet Jupiter took shape and wandered through the solar system. Scientists have theorized for years now that Jupiter probably was not always in its current orbit, which is about five astronomical units from the sun (Earth's distance from the sun is one astronomical unit).

One line of evidence suggesting a Jovian migration deals with the size of Mars. Mars is much smaller than planetary accretion models predict. One explanation for that is that Jupiter once orbited much closer to the sun than it does now. During that time, it would have swept up much of the material needed to create supersized Mars. But while most scientists agree that giant planets migrate, the timing of Jupiter's formation and migration has been a mystery. That's where the meteorites come in.

Meteorites known as CB chondrites were formed as objects in the early solar system--most likely in the present-day asteroid belt--slammed into each other with incredible speed. This new study, published in the journal Science Advances, used computer simulations to show that Jupiter's immense gravity would have provided the right conditions for these hypervelocity impacts to occur. That in turn suggests that Jupiter was near its current size and sitting somewhere near the asteroid belt when the CB chondrules were formed, which was about 5 million years after formation of the first solar system solids.

"We show that Jupiter would have stirred up the asteroid belt enough to produce the high-impact velocities necessary to form these CB chondrites," said Brandon Johnson, a planetary scientist at Brown University who led the research. "These meteorites represent the first time the solar system felt the awesome power of Jupiter."

Strange structures
Chondrites are a class of meteorites made up of chondrules, tiny spheres of previously molten material, and are among the most common meteorites found on Earth. The CB chondrites are a relatively rare subtype that have long fascinated meteoriticists.

Part of what makes the CB chondrites so interesting is that their chondrules all date back to a very narrow window of time in the early solar system. "The chondrules in other meteorites give us a range of different ages," Johnson said. "But those in the CB chondrites all date back to this brief period 5 million years after the first solar system solids."

But to Johnson, who studies impact dynamics, there is something else interesting about CB chondrites: They contain metallic grains that appear to have been condensed directly from vaporized iron.

"Vaporizing iron requires really high-velocity impacts," Johnson said. "You need to have an impact speed of around 20 kilometers per second to even begin to vaporize iron, but traditional computer models of the early solar system only produce impact speeds of around 12 kilometers per second at the time when the CB chondrites were formed."

So Johnson worked with Kevin Walsh of the Southwest Research Institute in Boulder, Colorado, to generate new computer models of the chondrule-forming period--models that include the presence of Jupiter near the present-day position of the asteroid belt.

Gravity boost
Big planets generate lots of gravity, which can slingshot nearby objects at high speeds. NASA often takes advantage of this dynamic, swinging spacecraft around planets to generate velocity.

Walsh and Johnson included in their simulations a scenario of Jupiter's formation and migration considered likely by many planetary scientists. The scenario, known as the Grand Tack (a term taken from sailing), suggests that Jupiter formed somewhere in the outer solar system.

But as it accreted its thick atmosphere, it changed the distribution of mass in the gassy solar nebula surrounding it. That change in mass density caused the planet to migrate, moving inward toward the sun to about where the asteroid belt is today. Later, the formation of Saturn created a gravitational tug that pulled both planets back out to where they are today.

"When we include the Grand Tack in our model at the time the CB chondrites formed, we get a huge spike in impact velocities in the asteroid belt," Walsh said. "The speeds generated in our models are easily fast enough to explain the vaporized iron in CB chondrites."

The most extreme collision in the model was an object with a 90-kilometer diameter slamming into a 300-kilometer body at a speed of around 33 kilometers per second. Such a collision would have vaporized 30 to 60 percent of the larger body's iron core, providing ample material for CB chondrites.

The models also show that the increase in impact velocities would have been short-lived, lasting only about 500,000 years or so (a blink of an eye on the cosmic timescale). That short timescale allowed the researchers to conclude that Jupiter formed and migrated at roughly the same time the CB chondrites formed.

The researchers say that while the study is strong evidence for the Grand Tack migration scenario, it doesn't necessarily preclude other migration scenarios. "It's possible that Jupiter formed closer to the sun and then migrated outward, rather than the in then out migration of the Grand Tack," Johnson said.

Whatever the scenario, the study provides strong constraints on the timing of Jupiter's presence in the inner solar system.

"In retrospect, it seems obvious that you would need something like Jupiter to stir the asteroid belt up this much," Johnson said. "We just needed to create these models and calculate the impact speeds to connect the dots."

Comment on this article using your Disqus, Facebook, Google or Twitter login.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only


Related Links
Brown University
The million outer planets of a star called Sol

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
Juno Mission Prepares for December 11 Jupiter Flyby
Pasadena CA (JPL) Dec 13, 2016
On Sunday, December 11, at 9:04 a.m. PST (12:04 p.m. EST, 17:04 UTC) NASA's Juno spacecraft will make its third science flyby of Jupiter. At the time of closest approach (called perijove), Juno will be about 2,580 miles (4,150 kilometers) above the gas giant's roiling cloud tops and traveling at a speed of about 129,000 mph (57.8 kilometers per second) relative to the planet. Seven of Juno ... read more

Early US astronauts faced uncertainty, danger and death

NASA Tech - it's all around us

NASA Communications Network to Double Space Station Data Rates

NASA's Exo-Brake 'Parachute' to Enable Safe Return for Small Spacecraft

Technical glitch postpones NASA satellite launch

After glitch, NASA satellite launch set for Wednesday

NASA Engineers Test Combustion Chamber to Advance 3-D Printed Rocket Engine Design

ULA launches eighth Wideband Global SATCOM satellite

Mars Rock-Ingredient Stew Seen as Plus for Habitability

ExoMars orbiter images Phobos

Mars One puts back planned colonisation of Red Planet

Opportunity team plot path forward to the 'Gully'

Chinese missile giant seeks 20% of a satellite market

China-made satellites in high demand

Space exploration plans unveiled

China launches 4th data relay satellite

Air New Zealand signs contract for Inmarsat's GX Aviation

UAE launches national space policy

European ministers ready ESA for a United Space in Europe in the era of Space 4.0

Nordic entrepreneurial spirit boosted by space

Japan launches 'space junk' collector

Teaching an old satellite new tricks

Orbital ATK to develop critical technology for in-orbit assembly

Decoding cement's shape promises greener concrete

Who needs a body? Not these larvae, which are basically swimming heads

Scientists examine bacterium found 1,000 feet underground

Rings around young star suggest planet formation in progress

ALMA finds compelling evidence for pair of infant planets around young star

Juno Mission Prepares for December 11 Jupiter Flyby

Research Offers Clues About the Timing of Jupiter's Formation

New Perspective on How Pluto's "Icy Heart" Came to Be

New analysis adds to support for a subsurface ocean on Pluto

The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.