Collision in the asteroid belt

[Swift]

spaceweather.com

Last week, astronomers working with the ATLAS project in Hawaii announced an astonishing change to asteroid 6478 Gault. The space rock had sprouted a tail. It is now gliding through the asteroid belt giving every appearance of being a comet. On Jan. 9th, Damian Peach of Selsey UK photographed the 6478 Gault and its 400,000 kilometer-long tail

What happened to 6478 Gault? A clue may be found in its lineage. Asteroid Gault is a member of the Phocaea family, a swarm of rocks in the inner asteroid belt that formed as a result of inter-asteroid collisions some 2.2 billion years ago. The family gets its name from its most massive survivor, 25 Phocaea, which is about 75 km in diameter.

Gault's tail may be a result of a recent collision. Researchers with the ATLAS project have looked at images of Gault in Dec. 2018 and Jan. 2019. Extrapolating its appearance backwards in time, they suggest that Gault hit another object in the asteroid belt in Nov. 2018. If that idea is correct, the tail would be debris from the crash.

[Superluminal]

Note the second asteroid below and to the left of Gault.

[slang]

Awesome! Yes, it does look like that is an object moving away 6478 Gault. Why such a long tail, rather than a cloud? Is it still shedding material?

[Roger E. Moore]

Photo.

https://www.virtualtelescope.eu/2019...d-12-jan-2019/

Asteroid (6478) Gault turns into a comet? – 11 and 12 Jan. 2019
by Gianluca Masi · 01/13/2019

[ngc3314]

Here's a shot from the predawn hours of 15 January from Kitt Peak (and then the clouds rolled in). The trail is not at all subtle - a bonus for imaging is that the asteroid is almost stationary in RA and dec just now.

[schlaugh]

Does the trail point away from the sun or is it parallel to the orbit of the asteroid?


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[Roger E. Moore]

I was thinking, if there was a collision then one might expect a puff of dust and debris flying away, but not necessarily a comet-like trail. I wonder if volatiles like water ice were exposed, or if the asteroid is spinning quickly now and throwing off dust.

[bknight]

Awesome! Yes, it does look like that is an object moving away 6478 Gault. Why such a long tail, rather than a cloud? Is it still shedding material?

Excellent question. This rather flies in the face of conventional wisdom of a collision, unless there is not sufficient gravity to keep the sphere of debris from the collision.

[Spacedude]

Holy Collisions Batman! Every Asteroid Destroys The Earth movie starts off just like this ;-)

[slang]

Here is a link to the original SpaceWeather.com page that Swift linked to, the story was on the frontpage then.

[ngc3314]

Does the trail point away from the sun or is it parallel to the orbit of the asteroid?

Definitely not along the orbit (which projects almost east-west just now). The trail runs about 15 degrees clockwise from the antisolar direction, if I'm reading the right column from the JPL Horizons output.

Smoothing that image, the trail can be traced for perhaps 326 arcseconds or 418,000 km in the plane of the sky. Its peak brightness is not quite monotonically falling with increasing distance from the asteroid (there is a very broad peak about 59 arcseconds away).

[George]

I had time to burn this rainy day, so ….

Asteroid tail collision.jpg

The time interval, t, (ok distance) was taken off two of the photos. They do "collide" after 9t, though I could be off 10%. The two dots opposite the collision points for both objects are the positions from the two photos. [I seem to like connecting dots this week. ]

[Superluminal]

I had time to burn this rainy day, so ….

Asteroid tail collision.jpg

The time interval, t, (ok distance) was taken off two of the photos. They do "collide" after 9t, though I could be off 10%. The two dots opposite the collision points for both objects are the positions from the two photos. [I seem to like connecting dots this week. ]

Has anyone determined if the second asteroid is a known object? My first thought was they passed very close to each other. Not likely that the second object impacted Gualt, or it would have a tail or debris cloud as well. Possibly a small moon tagging along with the second object, impacted Gualt. But space is really big. It could be a chance alignment of two objects that are millions of miles apart.

[slang]

I had time to burn this rainy day, so ….

Asteroid tail collision.jpg

The time interval, t, (ok distance) was taken off two of the photos. They do "collide" after 9t, though I could be off 10%. The two dots opposite the collision points for both objects are the positions from the two photos. [I seem to like connecting dots this week. ]

Which photos, the animation in the OP? If I understand what they wrote on the SpaceWeather article, the sequence shown there was taking during 60 minutes. But the suspected collision is suspected to have been in November last year. So that must then mean that the other moving dot must be non-related (didn't notice that on first read of the article). Or did I misunderstand and was it a bunch of exposures of each 60 minutes, taken over two months? Or did you use other images?

[George]

Has anyone determined if the second asteroid is a known object? My first thought was they passed very close to each other. Not likely that the second object impacted Gualt, or it would have a tail or debris cloud as well. Possibly a small moon tagging along with the second object, impacted Gualt. But space is really big. It could be a chance alignment of two objects that are millions of miles apart.

There must be a tale to this tail, and an impact, even if slight, is one reasonable explanation. It's difficult to determine from the video if the tail is shrinking since the image contrast looks different to me, but it kinda looks like it is. That would be another indication of an impact, if so.

[George]

Which photos, the animation in the OP? If I understand what they wrote on the SpaceWeather article, the sequence shown there was taking during 60 minutes. But the suspected collision is suspected to have been in November last year. So that must then mean that the other moving dot must be non-related (didn't notice that on first read of the article). Or did I misunderstand and was it a bunch of exposures of each 60 minutes, taken over two months? Or did you use other images?

Your link was very helpful in getting to the video, so all I did was hit Crtl-PrtScn to capture the beginning and end of that "60 minute" video. That required superb timing on my part and given my 400 level on Destiny 1, I think I came close. But are you suggesting that the video might not be WYSIWYG (some superpositioning)?

The time for "t" may be a little less than 60 minutes, but it does show that they were in proximity at -9t.

[slang]

Your link was very helpful in getting to the video, so all I did was hit Crtl-PrtScn to capture the beginning and end of that "60 minute" video. That required superb timing on my part and given my 400 level on Destiny 1, I think I came close. But are you suggesting that the video might not be WYSIWYG (some superpositioning)?

The time for "t" may be a little less than 60 minutes, but it does show that they were in proximity at -9t.

I'm thinking that if astronomers put the collision in november, then whatever that second object in the animation was, if it was close to 6478 Gault on Jan 8th or 9th it probably wasn't involved in "the" collision. Maybe coincidence?

[George]

I'm thinking that if astronomers put the collision in november, then whatever that second object in the animation was, if it was close to 6478 Gault on Jan 8th or 9th it probably wasn't involved in "the" collision. Maybe coincidence?

Yes, of course, great point. Wiki states the tail seemed to have been seen in November. This would make the intersection of the two paths highly(?) coincidental, as you suspect may be the case. It would be strange if it's not coincidental and the smaller object was something that got quit a separation jolt in January to give it the angle observed.

[ngc3314]

Apparently another event, brightening of the asteroid followed by production of a second tail.

Image from early on 31 January from Chile.

[DaveC426913]

Note the second asteroid below and to the left of Gault.

Indeed. Tracking the positions backward, they certainly are in the same place at the same time - at least within the margins of error of so few data points and high pixelation.

[ngc3314]

More and more events. From this morning (seen from La Palma), two distinct trails at once.

[publiusr]

Would the new trajectories take the remaining bodies near anything else down the road? This is is how the movie METEOR started after all--but probably nothing to worry us.

[schlaugh]

More and more events. From this morning (seen from La Palma), two distinct trails at once.

Your posts say "events." But are these events affecting the same body from the OP, or are these new impacts to different bodies? If multiple then are we seeing a cascade effect?

That would be interesting, however unlikely.

In any case, thank you for the updates.

ETA: Never mind, i read the fine print on the photos. Same body. Oh well, it was fun while it lasted.

[DaveC426913]

Indeed. Tracking the positions backward, they certainly are in the same place at the same time - at least within the margins of error of so few data points and high pixelation.

I have no idea how I missed all of posts 12 13 and 14, wherein you did the same thing I did - but better....