Jupiter blasted by 6.5 fireball impacts per year on average Further information

March 17th fireball captured by Gerrit Kernbauer and John McKeon

Image processed by Sebastian Voltmer

Credit: G. Kernbauer, J. McKeon, S. Voltmer

Animation of 17^th March impact observed by John McKeon

Credit: J McKeon

Jupiter is hit by an average of 6.5 objects per year that create impacts large enough to be visible from Earth, according to preliminary results from a worldwide campaign by amateur astronomers to observe the giant planet.  The estimate was presented at an international workshop on Jupiter for professional and amateur astronomers organised by Europlanet 2020 Research Infrastructure at the Observatoire de la Côte d’Azur in Nice, France.

Meteors impacting Jupiter’s upper atmosphere can create spectacular fireballs, such as the one observed by amateur astronomers Gerrit Kernbauer and John McKeon on 17^th March 2016. This was the fourth in a series of fireballs in Jupiter observed serendipitously by amateur astronomers since June 2010. Groups of amateurs worldwide have coordinated efforts to obtain improved estimates of the number of small bodies around Jupiter and how they interact with the planet.

Marc Delcroix, who coordinates a 60-strong group of amateur astronomers worldwide said, “Dramatic impacts with Jupiter can be captured with standard amateur equipment and analysed with easy-to-use software.  But to get a good estimate of how often these events occur, we need observers around the world who are willing to collaborate to create a programme of more-or-less continuous monitoring of Jupiter.  It takes time and commitment – observations of no impacts are just as important as detecting a fireball.  In 3 years since our programme started, amateur contributors from Europe, the US and Australia have analysed the equivalent of more than 56 days of videos – around 53 000 videos — without discovering an impact. 

This is a result in itself and, together with the reports of amateur astronomer John McKeon, has helped us come up with our preliminary estimate which slightly reduces previous estimates of the flux of impacting objects in Jupiter. We are now working to further enhance our software to improve its usability, while maintaining its simplicity and efficiency, to reach an even wider participation by amateurs. This should help in refining the impact estimations for Jupiter, and hopefully discover new impacts.”

Isshi Tabe and Dr Jun-ichi Watanabe, of the Association of Lunar and Planetary Observers (ALPO) in Japan, set up the Find Flash project following the observation of an impact flash by four Japanese amateur astronomers on 20th August 2010.

Tabe explained, “We recognised the importance of impact flashes for estimating the number of small bodies around Jupiter. We have perhaps more than 50 Japanese amateur astronomers in our association who take video images almost every night. We also have around 10 nights per year observation time on bigger telescopes in public and professional observatories, which allows us to employ a narrow band methane filter to detect fireballs in Jupiter’s upper atmosphere more efficiently. We’ve carried out the observational campaign for three years, but unfortunately we have never yet detected any impact flashes. We expect to have an increasing of number of observations over the next few years and to get valuable data both from bigger and smaller telescopes. However, in northern hemisphere of Earth, especially in Japan, we can only get consistently good observational conditions in summer, so it is important that we work together with other amateur groups around the world to get more data.”

John McKeon, who observed the St Patrick’s Day impact said, “Collaboration is extremely important in the amateur astronomer community. On March 28th I became aware that an amateur astronomer in Austria, Gerrit Kernbauer, had discovered a possible impact on Jupiter on March 17th. I remembered I had been filming Jupiter around the same time, with the intention of illustrating a double moon transit of the planet. I’d filmed a total of 207 short 55 second movies of the planet over a period of about 3 and half hours and had processed them to create a time-lapse animation. When I checked back through my videos, I found the impact in the second last video I had taken. This secondary observation helped to confirm the impact event. Having a hand in this discovery, and the input and support from other amateurs in the analysis of the event, has changed and improved my imaging process for the future.”

“The new estimate of 6.5 impacts a year of comparable size objects lies at the bottom part of our previous estimate of impacts in Jupiter,” said Ricardo Hueso of the University of the Basque Country and chair of the workshop’s scientific organising committee. “Constraining this number is important to improve our expectancies of observing large impacts in the planet, such as the Shoemaker-Levy impact in 1996 and the 2009 impact. Unfortunately, we are still dealing with the statistics of a very few number of impacts detected, but plans to improve our detection methods and perform systematic searches will help us to detect more of these objects. That will allow us to know more about the current architecture of the outer Solar System and the role of Jupiter in protecting the Earth from comparable impacts.”

Further information

• ALPO-Japan, Impact Flash Observing Group: http://alpo-j.asahikawa-med.ac.jp/Latest/Jupiter.htm

• Marc Delcroix’s  astronomy website: http://astrosurf.com/delcroix

• Software and impact detection project : http://www.astrosurf.com/planetessaf/doc/project_detect.shtml

Science contacts

Isshi Tabe
tabe@libra-co.com

Marc Delcroix
delcroix.marc@free.fr

John Mckeon
john.mckeon@gmail.com

Prof Ricardo Hueso Alonso
Escuela Técnica Superior de Ingeniería
Universidad del País Vasco/Euskal Herriko Unibertsitatea
Bilbao
+ 34 94601 4262
ricardo.hueso@ehu.es


Media contact

Anita Heward
Europlanet Media Centre
Tel: +44 7756 034243
anita.heward@europlanet-eu.org

Source: Europlanet

About Europlanet

Since 2005, Europlanet has provided Europe’s planetary science community with a platform to exchange ideas and personnel, share research tools, data and facilities, define key science goals for the future, and engage stakeholders, policy makers and European citizens with planetary science.

The Europlanet 2020 Research Infrastructure (RI) has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 654208 to provide access to state-of-the-art research facilities across the European Research Area and a mechanism to coordinate Europe’s planetary science community. The project builds on a €2 million Framework 6 Coordination Action and €6 million Framework 7 Research Infrastructure funded by the European Commission.  The Europlanet collegial organisation, linked by a Memorandum of Understanding (MoU), has a membership of over 70 research institutes and companies.

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A twist on planetary origins

An artist’s rendering of a protoplanetary impact. Early in the impact, molten jetted material is ejected at a high velocity and breaks up to form chondrules, the millimeter-scale, formerly molten droplets found in most meteorites. These droplets cool and solidify over hours to days. Image: NASA/California Institute of Technology

New study finds meteorites were byproducts of planetary formation, not building blocks

Meteors that have crashed to Earth have long been regarded as relics of the early solar system. These craggy chunks of metal and rock are studded with chondrules — tiny, glassy, spherical grains that were once molten droplets. Scientists have thought that chondrules represent early kernels of terrestrial planets: As the solar system started to coalesce, these molten droplets collided with bits of gas and dust to form larger planetary precursors.

However, researchers at MIT and Purdue University have now found that chondrules may have played less of a fundamental role. Based on computer simulations, the group concludes that chondrules were not building blocks, but rather byproducts of a violent and messy planetary process.

The team found that bodies as large as the moon likely existed well before chondrules came on the scene. In fact, the researchers found that chondrules were most likely created by the collision of such moon-sized planetary embryos: These bodies smashed together with such violent force that they melted a fraction of their material, and shot a molten plume out into the solar nebula. Residual droplets would eventually cool to form chondrules, which in turn attached to larger bodies — some of which would eventually impact Earth, to be preserved as meteorites.

Brandon Johnson, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences, says the findings revise one of the earliest chapters of the solar system.

“This tells us that meteorites aren’t actually representative of the material that formed planets — they’re these smaller fractions of material that are the byproduct of planet formation,” Johnson says. “But it also tells us the early solar system was more violent than we expected: You had these massive sprays of molten material getting ejected out from these really big impacts. It’s an extreme process.”

Johnson and his colleagues, including Maria Zuber, the E.A. Griswold Professor of Geophysics and MIT’s vice president for research, have published their results this week in the journal Nature.

High-velocity molten rock

To get a better sense of the role of chondrules in a fledgling solar system, the researchers first simulated collisions between protoplanets — rocky bodies between the size of an asteroid and the moon. The team modeled all the different types of impacts that might occur in an early solar system, including their location, timing, size, and velocity. They found that bodies the size of the moon formed relatively quickly, within the first 10,000 years, before chondrules were thought to have appeared.

Johnson then used another model to determine the type of collision that could melt and eject molten material. From these simulations, he determined that a collision at a velocity of 2.5 kilometers per second would be forceful enough to produce a plume of melt that is ejected out into space — a phenomenon known as impact jetting.

“Once the two bodies collide, a very small amount of material is shocked up to high temperature, to the point where it can melt,” Johnson says. “Then this really hot material shoots out from the collision point.”

The team then estimated the number of impact-jetting collisions that likely occurred in a solar system’s first 5 million years — the period of time during which it’s believed that chondrules first appeared. From these results, Johnson and his team found that such collisions would have produced enough chondrules in the asteroid belt region to explain the number that have been detected in meteorites today.

Falling into place

To go a step further, the researchers ran a third simulation to calculate chondrules’ cooling rate. Previous experiments in the lab have shown that chondrules cool down at a rate of 10 to 1,000 kelvins per hour — a rate that would produce the texture of chondrules seen in meteorites. Johnson and his colleagues used a radiative transfer model to simulate the impact conditions required to produce such a cooling rate. They found that bodies colliding at 2.5 kilometers per second would indeed produce molten droplets that, ejected into space, would cool at 10 to 1,000 kelvins per hour.

“Then I had this ‘Eureka!’ moment where I realized that jetting during these really big impacts could possibly explain the formation of chondrules,” Johnson says. “It all fell into place.”

Going forward, Johnson plans to look into the effects of other types of impacts. The group has so far modeled vertical impacts — bodies colliding straight-on. Johnson predicts that oblique impacts, or collisions occurring at an angle, may be even more efficient at producing molten plumes of chondrules. He also hopes to explore what happens to chondrules once they are launched into the solar nebula.

“Chondrules were long viewed as planetary building blocks,” Zuber notes. “It’s ironic that they now appear to be the remnants of early protoplanetary collisions.”

Fred Ciesla, associate professor of planetary science at the University of Chicago, says the findings may reclassify chondrites, a class of meteorites that are thought to be examples of the original material from which planets formed.

“This would be a major shift in how people think about our solar system,” says Ciesla, who did not contribute to the research. “If this finding is correct, then it would suggest that chondrites are not good analogs for the building blocks of the Earth and other planets. Meteorites as a whole are still important clues about what processes occurred during the formation of the Solar System, but which ones are the best analogs for what the planets were made out of would change.”

This research was funded in part by NASA.

Jennifer Chu | MIT News Office 

Source:  MIT News

Forty Thousand Meteor Origins Across the Sky

Forty Thousand Meteor Origins Across the Sky
Credit & Copyright: SonotaCo Network, Japan
Wallpaper 1280 x 1024

Wallpaper 1024 x 768

Explanation: Where do meteors come from? Visible meteors are typically sand-sized grains of ice and rock that once fragmented from comets.

Many a meteor shower has been associated with a known comet, although some intriguing orphan showers do remain. Recently, a group of meteor enthusiasts created a network of over 100 video cameras placed at 25 well-separated locations across Japan.

This unprecedented network recorded not only 240,000 optically bright meteors over two years, but almost 40,000 meteors seen by more than one station.

These multiple-station events were particularly interesting because they enabled the observers to extrapolate meteor trajectories back into the Solar System.

The resulting radiant map is shown above, with many well known meteor showers labelled by the first three letters of the home constellation.

Besides known meteor showers, eleven new showers were identified by new radiants on the sky from which meteors appear to flow.

The meteor sky is ever changing, and it may be possible that new shower radiants will appear in the future.

Research like this could also potentially identify previously unknown comets or asteroids that might one day pass close to the Earth.

Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
NASA Official: Phillip Newman Specific rights apply.
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