Hubble sees asteroid spouting six comet-like tails

Nov 07, 2013
This NASA Hubble Space Telescope set of images reveals a never-before-seen set of six comet-like tails radiating from a body in the asteroid belt, designated P/2013 P5. The asteroid was discovered as an unusually fuzzy-looking object with the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013. When Hubble returned to the asteroid on Sept. 23, the asteroid's appearance had totally changed. It looked as if the entire structure had swung around. One interpretation is that the asteroid's rotation rate has been increased to the point where dust is falling off the surface and escaping into space where the pressure of sunlight sweeps out fingerlike tails. According to this theory, the asteroid's spin has been accelerated by the gentle push of sunlight. The object, estimated to be no more than 1,400 feet across, has ejected dust for at least five months, based on analysis of the tail structure. These visible-light, false-color images were taken with Hubble's Wide Field Camera 3. Credit: NASA, ESA, and D. Jewitt (UCLA)

(Phys.org) —Astronomers using NASA's Hubble Space Telescope have identified what they can only describe as a never-before-seen "weird and freakish object" in the asteroid belt that looks like a rotating lawn sprinkler.

Normal asteroids should appear simply as tiny points of light. But this asteroid, designated P/2013 P5, has six comet-like tails of radiating from it like spokes on a wheel.

Because nothing like this has ever been seen before, astronomers are scratching their heads to find an adequate explanation for its out-of-this-world appearance.

"We were literally dumbfounded when we saw it," said lead investigator David Jewitt of the University of California at Los Angeles. "Even more amazing, its tail structures change dramatically in just 13 days as it belches out dust. That also caught us by surprise. It's hard to believe we're looking at an asteroid."

One interpretation is that the asteroid's rotation rate increased to the point where its surface started flying apart, ejecting dust in episodic eruptions starting last spring. The team rules out a recent asteroid impact scenario because a lot of dust would be blasted into space all at once, whereas P5 has ejected dust for at least five months.

The asteroid was discovered as an unusually fuzzy-looking object with the Pan-STARRS survey telescope in Hawaii. The multiple tails were discovered in Hubble images taken on Sept. 10, 2013.

When Hubble returned to the asteroid on Sept. 23, its appearance had totally changed. It looked as if the entire structure had swung around. "We were completely knocked out," Jewitt said.

Careful modeling by team member Jessica Agarwal of the Max Planck Institute for Solar System Research in Lindau, Germany, showed that the tails could have been formed by a series of impulsive dust-ejection events. She calculated that the first ejection event occurred on April 15 and the last one on Sept. 4. The rest sequentially erupted on July 18, July 24, Aug. 8, and Aug. 26. Radiation pressure from the Sun smears out the dust into streamers.

The asteroid could possibly have been spun up if the pressure of sunlight exerted a torque on the body. If the asteroid's spin rate became fast enough, Jewitt said, the asteroid's weak gravity would no longer be able to hold it together. Dust might avalanche downslope towards the equator, and maybe shatter and fall off, eventually drifting into space to make a tail. So far, only a small fraction of the main mass, perhaps 100 to 1,000 tons of dust, has been lost. The 700-foot-radius nucleus is thousands of times more massive.

Follow-on observations may show if the dust leaves the asteroid in the equatorial plane, and this would be pretty strong evidence for a rotational breakup. Astronomers will also try to measure the asteroid's true spin rate.

Jewitt's interpretation implies that rotational breakup must be a common phenomenon in the belt; it may even be the main way in which small asteroids die. "In astronomy, where you find one, you eventually find a whole bunch more," Jewitt said. "This is just an amazing object to us, and almost certainly the first of many more to come."

The paper from Jewitt's team appears online in the November 7 issue of The Astrophysical Journal Letters.

Explore further: Astronauts to get 'ISSpresso' coffee machine

More information: dx.doi.org/10.1088/2041-8205/778/1/L21

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tadchem
1 / 5 (8) Nov 07, 2013
The existence of *any* tails is an indication that the object is emitting matter thermally. It is heating up, which indicates that it was recently cooler, and presumably a little further from the sun.
I would like to see the orbital elements on this one - betting it's an inbound comet.
scottfos
not rated yet Nov 07, 2013
could it have been "knocked off course"? this is cool, i look forward to tracking this story.
LagomorphZero
1 / 5 (7) Nov 07, 2013
It would be cool to see some spectrometry performed on the tails to help identify the matter composition.
Zephir_fan
Nov 07, 2013
This comment has been removed by a moderator.
Sionnach
2.6 / 5 (5) Nov 07, 2013
LagomorphZero,

From the cited paper, it appears this was a very difficult observation, a target of opportunity so to speak. Hubble time is very limited. I would think that the kind of data you are interested in will be coming in from ground based observatories during the next year to 18 months. The journal article is on a subscriber service but you can download the preprint in PDF format here. They describe the observation techniques and initial findings.

http://arxiv-web3...311.1483
britton_beckham
1 / 5 (14) Nov 07, 2013
Asteroid = comet; Comet = Asteroid.

Asteroid = electrically neutral (to its surroundings) chuck of matter in space.
Comet = electrically imbalanced (to its surroundings) chunk of matter in space.

What you are seeing here is electric discharge (plasma in glow/arc mode)... most likely from one of the recent X-class flares from the sun that caught up to it.
cantdrive85
1 / 5 (14) Nov 08, 2013
astronomers are scratching their heads to find an adequate explanation for its out-of-this-world appearance.

And they won't find a legit one until they drastically rethink things.

One interpretation is that the asteroid's rotation rate increased to the point where its surface started flying apart, ejecting dust in episodic eruptions starting last spring.

That explanation requires an adjustment on another quote as follows...

Instead of;
"We were literally dumbfounded when we saw it," said lead investigator David Jewitt of the University of California at Los Angeles.


it should read;
"We are literally dumb for even considering the explanation given above!"
Kedas
2.3 / 5 (3) Nov 08, 2013
That person on board that was responsible for letting the engines look like comet tails is soo going to get fired.

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