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Astronomie - New Impact Flash Seen at Jupiter

29.05.2017

Yet another Jovian fireball? Amateur astronomers record a rare impact flash in Jupiter's north polar region. 

5th Jupiter flash on record

On May 26 during the early evening local time, Sauveur Pedranghelu recorded the flash of meteoroid impact in Jupiter's north polar region at the CMII longitude of 160°. It's the 6th recorded impact observed at the planet.
Sauveur Pedranghelu with processing by Marc Delcroix

Jupiter just got beaned for the 5th time! On the evening of May 26, between 19:24.6 UT and 19:26.2 UT, Sauveur Pedranghelu, a French amateur from Corsica, detected a impact flash live on video in Jupiter's north polar region.

The flash was very brief, lasting only about 0.7 second, and displayed two brightness peaks. A bright dot — about the size of Europa when seen in transit — marked the site of impact at latitude ~51°North and central meridian longitudes CMI = 74°; CMII = 159° and CMIII = 292°. The position is a little east of Oval BA, a.k.a. Red Spot Jr., located on the same face of the planet in the opposite hemisphere.

Marc Delcroix, who coordinates a worldwide group of Jupiter observers, posted an e-mail about the the discovery to various groups. Within a day of the news, a second video by Thomas Riessler of Dettenhausen, Germany showed an identical pinpoint flash between 19:24.6 UT and 19:25.0 UT confirming Pedranghelu's observation. The estimated duration of the fireball from that video was ~0.87 seconds.

Jupiter watchers are excitedly training telescopes and cameras on the giant planet in hopes of seeing if the meteoroid explosion left any traces similar to the dark spots in similar impacts of the past or possibly a bright spot when photographed through narrowband methane filters. Early observations haven't turned up a trace ... yet. On May 28 from the Philippines, planetary imager Christopher Go couldn't detect anything certain at the site, writing on his website:

"There is no brightening of the impact region in methane band and nor is there any noticeable impact remnant."

Impact confirmed!

Once word got out about the May 26 impact, a second video made by Thomas Riessler quickly came to light.
Thomas Riessler with processing by Marc Delcroix

Perhaps larger telescopes may fish up something, but either way, it wouldn't hurt to keep the site in view. Visual observers and images worldwide are encouraged to look for an impact remnant. To determine the longitude of Jupiter's central meridian, i.e. when a particular longitude is squarely centered on the face of the planet, click here and enter the UT time and date when you'll be observing the planet. You'll be looking for times when longitude 159° (CMII) is well-placed.

Still hoping for a sign

This photo of Jupiter, taken May 28 at 11:34 UT, doesn't show an obvious impact scar at the site of the observed flash (circled area). Oval BA is squarely on the central meridian near the bottom of the image. 
Christopher Go

The first-ever confirmed impact at Jupiter occurred in July 1994, when 21 fragments of Comet Shoemaker-Levy 9 crashed into the planet in succession, creating a striking belt of sooty, dark impact spots girdling the planet. Alert to the possibility that comet and asteroid impacts might be more common than thought, amateurs began keeping a closer eye on Jove in hopes of catching sight of additional flashes. Cheap video cameras made it possible to continuously monitor the planet.

Comet crash

Comet Shoemaker-Levy 9 broke up into many fragments which later slammed into Jupiter’s southern hemisphere one after another to create impact flashes and a string of dark blotches in July 1994.
NASA/ESA

15 years later on July 19, 2009, Australian amateur Anthony Wesley hit pay dirt when he recorded a dark spot in Jupiter's clouds spawned by a colliding meteoroid. No one saw or recorded the actual flash of impact, but there was no doubt about it being the real thing. Wesley's discovery was soon followed by three additional Jovian flashes recorded by amateurs on June 3, 2010August 20, 2010 and March 17, 2016.


Jupiter impact on June 3, 2010 discovered by Anthony Wesley and Christopher Go

Two factors make Jupiter a great place to look for asteroid and comet collisions. First, the planet’s powerful gravity can draw in debris that happens to stray too close. Second, that same gravity accelerates even small objects to such high speeds that you get maximum bang for your buck.


Jupiter impact on March 17, 2016 by John McKeon

According to Bad Astronomy blogger Phil Plait: “On average (and ignoring orbital velocity), an object will hit Jupiter with roughly five times the velocity it hits Earth, so the impact energy is 25 times as high.” That could mean that a fairly small object caused this most recent flash.

Who knows what you might see the next clear evening when Jupiter, standing high and bright, extends an invitation.

Quelle: Sky&Telescope

 

 
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