The nucleus of a comet undone: Scientists monitor Hergenrother's breakup

Nov 05, 2012
Comet 168P-Hergenrother was imaged by the NOAO/Gemini telescope on Nov. 2, 2011 at about 6 a.m. UTC. Credit: NASA/JPL-Caltech/NOAO/Gemini

(—The Hergenrother comet is currently traversing the inner-solar system. Amateur and professional astronomers alike have been following the icy-dirt ball over the past several weeks as it has been generating a series of impressive outbursts of cometary-dust material. Now comes word that the comet's nucleus has taken the next step in its relationship with Mother Nature.

"Comet Hergenrother is splitting apart," said Rachel Stevenson, a post-doctoral fellow working at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Using the National Optical Astronomy Observatory's on top of Mauna Kea, Hawaii, we have resolved that the nucleus of the comet has separated into at least four distinct pieces resulting in a large increase in dust material in its coma."

With more material to reflect the sun's rays, the comet's coma has brightened considerably.

"The comet fragments are considerably fainter than the ," said James Bauer, the deputy principal investigator for NASA's NEOWISE mission, from the California Institute of Technology. "This is suggestive of chunks of material being ejected from the surface."

The comet's fragmentation event was initially detected on Oct. 26 by a team of astronomers from the Remanzacco Observatory, using the Faulkes North in Haleakala, Hawaii. The initial fragment was also imaged by the WIYN telescope group at Kitt Peak National Observatory in Arizona.

For those interested in viewing Hergenrother, with a larger-sized telescope and a dark sky, the comet can be seen in between the constellations of Andromeda and Lacerta.

The orbit of comet 168P/Hergenrother comet is well understood. The , nor any of its fragments, are a threat to Earth.

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2.6 / 5 (9) Nov 05, 2012
When Biela broke up, back in 1846, a luminous bridge of material was observed to join the fragments -- which were estimated to be 250,000 kilometers apart. Ignatius Donnelly reported that a similar "bright jet was seen between the two heads" when the two fragments returned in 1852.

Comet Holmes 17P was observed to increase in luminosity "for no apparent reason" as well. Holmes' coma would eventually expand to five times the volume of the Sun, based upon a nucleus whose diameter was observed to be 3.6 km after the flare-up. The brightness flared by a factor of 1 million.

Such observations are strong investigative leads that the dirty snowball theory is wrong. There are many more examples which support the same point: That comets owe their sudden, unexplained brightening at great distances from the Sun to sudden changes in the solar wind plasma, and that connecting bridges are indicative of electrical currents between fragments.
3 / 5 (10) Nov 05, 2012
Such observations are strong investigative leads that the dirty snowball theory is wrong

Wow. At least go look at the wiki page. The dirty snowball analogy is obsolete since at least a couple years ago. We have really great pictures of two comet nuclei. The surfaces are dusty/rocky and they are darker than asphalt. The dark surface is what allows them to absorb enough heat from the sun to make them vent frozen gas from inside. Over repeated trips around the sun and back out, they freeze and melt on the inside repeatedly. This is what breaks them up eventually. Once broken open they out-gas vast amounts of fresh material suddenly exposed to sunlight for the first time ever.

We even have samples of comet dust brought back to Earth by the Spacedust mission.

The jets are not electric arcs. We have gotten really close and taken pictures.
1 / 5 (1) Nov 05, 2012
Ooops, that should be Stardust mission I think
2.3 / 5 (3) Nov 06, 2012
GSwift, Hannes was commenting physorg's bolded subheader acknowledging the dirty snowball model

"Amateur and professional astronomers alike have been following the icy-dirt ball over the past several ..."
1 / 5 (2) Nov 19, 2012
Each Comet Nucleus is made up of dark matter. Each is its own low energy nuclear reactor. They are very dangerous. This is why they do not "MELT" when passing around/through the sun. They can trigger massive CME's because the sun is swarming with orbital dark matter which orbits through and around regular matter. They gravitationally attract and annihilate each other. It is all on my blog @

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