Starship Asterisk*

P2010 A2: Unusual Asteroid Tail Implies Powerful Collision

Explanation: What is this strange object? First discovered on ground based LINEAR images on January 6, the object appeared unusual enough to investigate further with the Hubble Space Telescope last week. Pictured above, what Hubble saw indicates that P/2010 A2 is unlike any object ever seen before. At first glance, the object appears to have the tail of a comet. Close inspection, however, shows a 140-meter nucleus offset from the tail center, very unusual structure near the nucleus, and no discernable gas in the tail. Knowing that the object orbits in the asteroid belt between Mars and Jupiter, a preliminary hypothesis that appears to explain all of the known clues is that P/2010 A2 is the debris left over from a recent collision between two small asteroids. If true, the collision likely occurred at over 15,000 kilometers per hour -- five times the speed of a rifle bullet -- and liberated energy in excess of a nuclear bomb. Pressure from sunlight would then spread out the debris into a trailing tail. Future study of P/2010 A2 may better indicate the nature of the progenitor collision and may help humanity better understand the early years of our Solar System, when many similar collisions occurred.

<< Previous APOD

Discuss Any APOD

Next APOD >>

[/b]

If the asteroid is 140m across then its gravity will be pretty low. A nuclear explosion would pretty much wipe it out and debris would be flung much further that appears to be the case, and the moulding by light suggests something a lot more gentle. Was there a secondary impact - that would be needed to account for the structure near the asteroid?
I dont know the orbit of this object but I wouldnt be surprised to hear that has been getting warmer and a captured comment fragment on its surface just got boiled.

I can only see one asteroid in the picture. The x probably shows the trajectory of the other one. Maybe it was totally annihilated?

What does "recent" collision mean in this context?

Just wondering if the Sun (a UK paper) ripped off the APOD story and included a fake interview. They didn't credit the original discoverer...just wanted to submit it for someone's awareness. Like I said, I'm not sure, but it seems a bit odd...

Here's the link to the Sun story: http://www.thesun.co.uk/sol/homepage/ne ... ffins.html

Ahahaha... The Sun truly is a disgrace to Britain.

geckzilla wrote:Ahahaha... The Sun truly is a disgrace to Britain.

Why do you assume that the Sun didn't phone RJN on this one.
It's SOP for publications to do so.

That Sun story is bizarre. Thanks for pointing it out -- I had no idea. I did not give them an interview. They did not even ask. They must have copied the APOD text and then attributed to me as quotes. Yet they did not cite APOD explicitly. This brings up the another question -- how did they know who wrote that APOD text? - RJN (Resident Boffin)

A good guess. If Jerry's name came first in the footer, they probably would have put his name there instead.

Back in October 2007, I thought this is exactly what happened to Comet Holmes, based on the sudden brightening of Comet Tempel II when hit by Deep Impact years before. Perhaps an object no bigger than a large building hit Holmes, and the debris blew off pointing away from us, so we do not see the long tail that this angle of impact produced.

It will be interesting to watch the trajectory of debris in the next few months. Will our relative orbits allow Hubble to get a few more shots?

The picture is even better rotated 180 degrees, imho

wwooten wrote:Back in October 2007, I thought this is exactly what happened to Comet Holmes, based on the sudden brightening of Comet Tempel II when hit by Deep Impact years before. Perhaps an object no bigger than a large building hit Holmes, and the debris blew off pointing away from us, so we do not see the long tail that this angle of impact produced.

It seems to me likely that Comet Holmes collided with
a former (broken off) piece of itself both in 2007 & back in 1892.

http://en.wikipedia.org/wiki/Comet_Holmes wrote:
Comet Holmes was discovered by Edwin Holmes on November 6, 1892 while he was conducting regular observations of the Andromeda Galaxy (M31). Its discovery in 1892 was possible because of an increase in its magnitude similar to the 2007 outburst; it brightened to an approximate magnitude of 4 or 5 before fading from visibility over a period of several weeks.

Comet Holmes:

Code: Select all

Aphelion distance: 	  5.183610 AU
Perihelion distance: 	2.053218 AU
Semi-major axis: 	    3.618414 AU
Inclination: 	       19.1126°

However, since the 2007 Holmes outburst took place shortly after (the May 4th)
Holmes 2.05 AU perihelion passage one can now envision Holmes having possibly
collided with a high inclination piece of Flora asteroid debris in the inner belt:

http://asterisk.apod.com/vie ... ra#p115226

I did send a note to The Sun to try and verify where they obtained the information in the story. I just thought it was weird that the text in their story was transposed from the APOD story. And when I didn't see Mr. Jewitt mentioned in the story, I was a little concerned. I don't want to be "that guy" who complains and this is the first I've ever done so, but I don't believe it's right to run a story without properly citing it, especially when it comes to someone's discovery.

In the end, I'm glad to see they ran the story...the more exposure this type of science is given, the better.

...Except that The Sun likes to try to convince people that aliens are in town every chance it gets, including this one, even though there's never a shred of evidence. Makes money. Whatever you do, do not read the comments posted after the article. I think they will osmose bits of your brain through your skull just by being exposed to them.

So what are the chances of actually figuring out what happened to the asteroids? How long ago do we suppose they collided?

geckzilla wrote:So what are the chances of actually figuring out what happened to the asteroids?
How long ago do we suppose they collided?

Well, I'm sure folks are frantically searching archived data to see when the tail was first visible.

Future Hubble images of the evolution of the "X" pattern should also be useful.

P/2010 A2 is close to Mars so you might want to check out Wally's astronomical photo.

Orbit and position of Comet P/2010 A2 (LINEAR).
Image created with the program C2A. Credit: Carl Hergenrother.

The Dawn spacecraft is about 4 times closer than us to P/2010 A2
and should remain close to P/2010 A2 for quite a while as it converges on Vesta.
I wonder if they are taking any pictures.

When (and if ) Dawn reaches Vesta it will be interesting to see how cratered Vesta is.

It looks like a Klingon Battlecruiser...

alfredogracia wrote:It looks like a Klingon Battlecruiser...

... or perhaps an old-fashoned bottle-with-fins rocket. If so, the vapor trail would mark the path of its retrorocket exhaust (which it would have been falling into, after all) and the bright spot at the tip of the "fin" is actually light from an attitude jet (which explains why it isn't lined up as one would expect if it had been firing retros; it rotated for some reason and is now controlling that rotation).

No, I don't think so. Humans are too darned good at picking out plausible patterns in random noise. But it can be entertaining to play "what if".

Bad Astronomy: Hubble captures picture of asteroid collision!

Now, let me just take a moment and say HOLY HALEAKALA WHAT WE’RE SEEING HERE IS THE COLLISION BETWEEN TWO PREVIOUSLY UNDISCOVERED ASTEROIDS THAT EXPLODED LIKE THERMONUCLEAR WEAPONS WHEN THEY IMPACTED!!!

Phew. OK, I feel better. I needed to get that off my chest.

Your theory is plausible, but if you look very closely, you will clearly see the cloaked outline of a Klingon Bird of Prey. We are not alone!!

How much of that Hubble image granularity is just plain grain in a noisy photo and how much is actual space grit reflecting light, I wonder.

Would be nice to see another image. Is this bright enough for a ground based shot? Granted, it's probably not very big.

-Noel

The tail of this object is evidently comprised of many chunks of stuff large enough to be individually detected by Hubble. I don't know what size rocks can be resolved by Hubble at this distance, but it's pretty evident that these are big rocks. If so, how could the whimpy light pressure from the sun affect them so strongly that they were forced to group into a compact, well organized tail? Doesn't make sense to me...

Don

Oldfart wrote:The tail of this object is evidently comprised of many chunks of stuff large enough to be individually detected by Hubble. I don't know what size rocks can be resolved by Hubble at this distance, but it's pretty evident that these are big rocks. If so, how could the whimpy light pressure from the sun affect them so strongly that they were forced to group into a compact, well organized tail? Doesn't make sense to me...

There is a big difference between being able to detect something and being able to resolve it. None of the material from this object is large enough to be resolved by Hubble's camera. But there are thousands or millions of individual components bright enough to be detected. Even fine dust that is lit by the Sun is easily detectable. Material smaller than about a centimeter is highly affected by both the solar wind and by radiation pressure.

Chris, thanks for trying to help me figure out what's going on here. I say "trying", because I'm still a bit fuzzy about this. As in:

It was my notion that the Hubble photo resolved the tail, showing that it was comprised of thousands of individual points of light, and I assumed that each little point of light resulted from sunlight reflecting from an object like a rock or something. You seem to suggest that these objects could actually be quite small, perhaps centimeter-size pebbles or even smaller. Is that right? If so, I guess I was just WAY underestimating Hubble's ability to see tiny things that far away. Thanks for clarifying!

Don

I think your initial hunch was correct, Oldfart. Chris was just making sure you were making the distinction between detecting and resolving. The grain present in the image is evenly distributed and perceived granules in the tail are probably just part of that grain.