An amateur astronomer has discovered a possible new impact flash in Jupiter’s equatorial region.

Possible Jovian impact flash
A possible new impact at Jupiter appears in this image taken by José Luis Pereira around 22:39 UT (18:39 EDT) on September 13th. Marc Delcroix processed the photo. North is up and the planet rotates from east to west (left to right).
José Luis Pereira

Did Jupiter just get smacked again? Amateur astronomer José Luis Pereira of Brazil just discovered a probable new impact at the gas giant on September 13th at around 22:39:30 UT (18:39:30 EDT). Weather conditions were poor at the time, but Pereira decided to search anyway for possible flashes with DeTeCt software. The free program, created by planetary observer Marc Delcroix, is a useful tool to check for transient events such as planetary impacts.

Watch as the flash quickly appears and fades at the upper right in this snippet of video. The video is looped for easy re-watching.
José Luis Pereira

Despite poor conditions Pereira suspected something on his first video and ran DeTeCt to check it out. The program alerted him that there was a high probability that what he saw was indeed a collision. He immediately sent a message to Delcroix for confirmation.

If confirmed, it would be the eighth recorded impact at Jupiter since the first in July 1994, when fragments of sundered Comet Shoemaker-Levy 9 slammed into the planet and left a trail of prominent dark scars.

If you know the current longitude of the central meridian (CM) and a cloud feature's longitude, you can plan your observing session to see it best when that longitude is within about an hour of either side of the CM.
Sky & Telescope

Jupiter rotates rapidly, coming round in just under 10 hours. To find a potential dark spot in the impact's wake, you'll need to know its latitude and longitude. But because the planet isn’t a rigid body, its rotation rate varies some by latitude. Equatorial regions spin fastest and polar regions slower. That’s why three systems are used to determine a feature's longitude: System I for locations within 10° of the equator (for the current flash), System II for all higher latitudes, and System III to match the rotation of the planet’s magnetosphere and Jupiter’s official rotation rate. Often, all three longitudes will be given for completeness.

José Pereira portrait
“For me it was a moment of great emotion as I have been looking for a record of this event for many years,” said Pereira. He used his 275-mm f/5.3 Newtonian reflector equipped with a QHY5III462C imaging camera, Televue Powermate 5× (yielding f/26.5) and IR and UV cut-off filters to make the discovery from São Caetano do Sul in Brazil.
José Luis Pereira

Pereira captured the flash at latitude –5.5° and longitude 105.7° (System I / L1), 83.3° (System II / L2), and 273.4° (System III / L3). To determine the current or a future Jovian longitude in either system, use the Arkansas Sky Observatory’s Jupiter Central Meridian site and input the desired UT time. Click here to convert your local time to UT.

Amateurs are encouraged to check any videos or photographs taken within 5 minutes of the impact time to confirm the event. I also hope you’ll be watching the site for any impact scar that might appear in the coming nights. Happily, a dark marking should stand out well against the pale Equatorial Zone.

This is a developing story. Updates are found below.

This video was recorded at Astroqueyras, St-Véran, France at 22:29:30 UT, September 13, 2021 by Thibaut Humbert, Stéphane Barré, Alexis Desmougin and Didier Walliang, who are members of the Société Lorraine d'Astronomie (SLA). The moon Io and its shadow are seen at right.

** Update September 15 — At least 7 observers independently saw or recorded the flash according to Marc Delcroix. That includes 1 from Brazil, 2 from Germany, 3 from France and 1 from Italy. You'll find the French videos and still photos here.

Jupiter impact flash
German amateur Harald Paleske eliminated the possibility of a passing airplane or satellite flare after examining his video frames. This one shows the moment of impact on September 13th.
Harald Paleske

German amateur astronomer Harald Paleske also captured images of the impact through his 16-inch reflector. Despite poor seeing at the time, the 2-second-long flash is obvious. I've seen a rough estimate of 100 meters (328 feet) for the impactor's size. There are no reports of dark impact spots at this time.


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Comments


Image of Anthony Barreiro

Anthony Barreiro

September 14, 2021 at 10:16 pm

Spaceweather.com reported that German astronomer Harald Paleske observed an impact at 22:39:27 UT on Sept. 13th. The spaceweather.com report includes Paleske's image, and unfortunately either Paleske or spaceweather seems to have mistakenly reversed latitude and longitude, reporting latitude 106.9° (CM1), and longitude +3.8°.

Here's the spaceweather report:

https://spaceweather.com/archive.php?view=1&day=15&month=09&year=2021

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Bob King

September 15, 2021 at 12:22 am

Hi Anthony,

That's strange — yes, it appears Spaceweather is in error and reversed the numbers. The values I used come direct from José Pereira through personal communication.

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adina_guta@yahoo.com

September 15, 2021 at 4:47 pm

Hi , my name is Adina I'm not as experienced as you but I have a Q why the asteroid or comet whatever it was had no trail? When Schewmaker-Levy9 blasted good ol' Jupiter A. It had trails all 9 pieces plus the aftermath it looked dark not shiny. Why is that ? Ty.

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Bob King

September 15, 2021 at 4:56 pm

Hi Adina,

Great question! The reason is because astronomers discovered Shoemaker-Levy 9 when it was a comet, predicted its collision with Jupiter and then watched as big fragments of the comet created dark impact scars in Jupiter's cloud tops. In this case, no one knew in advance when this latest impact would occur. That's probably because it was a single, relatively small object. Impacts happen at Jupiter all the time, but most are small objects and certainly many are missed. It was dedication and luck that led amateurs to spot this one. And while it produced a flash, not all impacts create obvious dark patches like S-L9. It depends on the size and speed of the impactor. That's not to say a blotch, however big or small, won't develop in the wake of the bright flash in the coming days. That's why we're all watching the planet closely right now through our telescopes. I encourage you to click the link in the story "8th recorded impact" to learn more about previous hits.

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Alain Maury

September 15, 2021 at 9:49 pm

The french amateurs and videos are visible here : https://www.cieletespace.fr/actualites/3-telescopes-amateurs-francais-detectent-un-impact-sur-jupiter

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Alain Maury

September 15, 2021 at 9:50 pm

I meant the french amateurs photos and videos...

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Bob King

September 16, 2021 at 12:22 am

Excellent, thank you, Alain!

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vanquirius

September 16, 2021 at 6:54 pm

Hi there! How big would you estimate the impact object to be?

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Bob King

September 17, 2021 at 12:00 am

Hi vanquirius,

The best estimate I've heard — and it's just a rough estimate — is 100 meters or 328 feet.

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