Strange Comet

[Jacques]

From http://spaceweather.com/

Yesterday, Comet Holmes shocked sky watchers with a spectacular eruption, brightening almost a million-fold from 17th to 2.5th magnitude in a matter of hours. The comet is now visible to the naked eye--even from light polluted cities--high in the northern sky after sunset

I thought that might interest some of you.

I wonder what caused that brightening... Any idea ?

May be the comet fragmented ...

[Royston]

Interesting, the first thing I thought was a gas pocket that had heated, or had ignited due to a collision...but the images of the comet look spherical, as though the change in luminosity is uniform, and you'd expect to see the ejection of gases, a small tail on the comet.

 

Here's more from space.com...

 

http://www.space.com/spacewatch/071025-comet-holmes.html

 

If the comet had fragmented, due to collision or an increase in pressure from within, I'm sure you'd still see deformation of some sort, not a bright sphere. Perhaps somebody else knows more on the subject, or has an idea of what could of caused this ?

[iNow]

It was the subject of today's Astronomy Picture of the Day (APOD):

 

 

 

http://antwrp.gsfc.nasa.gov/apod/ap071026.html

 

 

 

Explanation: Comet 17P/Holmes stunned comet watchers across planet Earth earlier this week. On October 24, it increased in brightness over half a million times in a matter of hours. The outburst transformed it from an obscure and faint comet quietly orbiting the Sun with a period of about 7 years to a naked-eye comet rivaling the brighter stars in the constellation Perseus. Recorded on that date, this view from Tehran, Iran highlights the comet's (enhanced and circled) dramatic new visibility in urban skies. The inset (left) is a telescopic image from a backyard in Buffalo, New York showing the comet's greatly expanded coma, but apparent lack of a tail. Holmes' outburst could be due to a sudden exposure of fresh cometary ice or even the breakup of the comet nucleus. The comet may well remain bright in the coming days.

 

 

I've loved that site for years. They always offer very robust and dense explanations, and the pictures are often stunning.

[Royston]

So Jacques is probably right, that the comet fragmented, or has broken up a little.

 

Nice pic.

[Jacques]

Last evening I observed it with my telescope ! It was a nice sight and I see that the form is more elleptical. Very bright and very big ( about 5 time the apparent diameter of jupiter). I will keep an eye on it.

 

Look at how the size evolved in 1 day !!!

Diameter comparaison

[iNow]

Today's APOD had another tidbit on this. I'll let you click the link if you wish to view the pic.

 

 

http://antwrp.gsfc.nasa.gov/apod/ap071029.html

 

Explanation: What's happened to Comet Holmes? A normally docile comet discovered over 100 years ago, Comet 17P/Holmes suddenly became nearly one million times brighter last week, possibly over just a few hours. In astronomical terms, the comet brightened from magnitude 17, only visible through a good telescope, to magnitude 3, becoming visible with the unaided eye. Comet Holmes had already passed its closest to the Sun in 2007 May outside the orbit of Mars and was heading back out near Jupiter's orbit when the outburst occurred. The comet's sudden brightening is likely due to some sort of sunlight-reflecting outgassing event, possibly related to ice melting over a gas-filled cavern, or possibly even a partial breakup of the comet's nucleus. Pictured above through a small telescope last Thursday, Comet Holmes appeared as a fuzzy yellow spot, significantly larger in angular size than Earth-atmosphere blurred distant stars. Although Comet Holmes' orbit will place it in northern hemisphere skies for the next two years, whether it will best be viewed through a telescope or sunglasses remains unknown.

[Pangloss]

whether it will best be viewed through a telescope or sunglasses remains unknown.

 

Cute. Wouldn't THAT be an interesting event!

[iNow]

This thing is major. Rarely have I seen 3 APOD features of the same object in such a short time. However, the comet was AGAIN featured today:

 

 

http://antwrp.gsfc.nasa.gov/apod/ap071103.html

 

 

 

 

Explanation: Surprising Comet Holmes remains easily visible as a round, fuzzy cloud in the northern constellation Perseus. Skywatchers with telescopes, binoculars, or those that just decide to look up can enjoy the solar system's latest prodigy as it glides about 150 million kilometers from Earth, beyond the orbit of Mars. Still expanding, Holmes now appears to be about 1/3 the size of the Full Moon, and many observers report a yellowish tint to the dusty coma. A golden color does dominate this telescopic view recorded on November 1, showing variations across the coma's bright central region. But where's the comet's tail? Like any good comet, Holmes' tail would tend to point away from the Sun. That direction is nearly along our line-of-sight behind the comet, making its tail very difficult to see.

 

 

 

So, has anyone read any plausible explanations of this? It's very strange, indeed.

[Jacques]

We can now see the tail!

 

Strange comet indeed, it's the second time that comet burst like that. The first was in 1892, an outburst that led to the comet's discovery by British astronomer Edwin Holmes.

The comet orbit is all between mars and jupiter so maybe a collision with an astroid may be responsible for that outburst, but the comet is out of the ecliptic plane... An other hypothesis would be that of tide effect from jupiter but it still very far from jupiter.

May be we will need to send a space probe to solve the mystery

[iNow]

I love the coverage this is getting on APOD. Here is a gorgeous shot, credit given to Ivan Eder and (inset) Paolo Berardi. The primary image was captured near Budapest, Hungary, and the inset from L'Aquila, Italy.

 

It sort of makes me feel like a kid again.

 

 

http://antwrp.gsfc.nasa.gov/apod/ap071110.html

 

 

 

 

Explanation: A beautiful blue ion tail has become visible in deep telescopic images of Comet Holmes. Pointing generally away from the Sun and also planet Earth, the comet's ion tail is seriously foreshortened by our extreme viewing angle. Still, enthusiastic comet watchers have remarked that on the whole, the compact but tentacled appearance suggests a jellyfish or even a cosmic calamari. This stunning view of the comet's greenish coma and blue tail was recorded on November 4 in clear skies near Budapest, Hungary. The colors are caused by molecules in the tenuous gas, like C2 (green) and CO+ (blue), fluorescing in sunlight. In a more recent development, the dramatic inset is a deep image from L'Aquila, Italy on November 8, showing the ion tail disconnecting from the comet.

[brainfart94]

http://news.yahoo.com/s/space/20071115/sc_space/incrediblecometbiggerthanthesun

 

And it gets yet even bigger!

The diameter of the comet's coma (269,900mi)grows larger than the sun's diameter(264,900mi), making it the largest thing in the solar system.

[ajb]

Get a pair of binoculars and have a look at it. I was amazed just how bright and big it is. It is very easy to find.

[iNow]

It truly is amazing.

 

 

Here's another from today:

 

 

http://antwrp.gsfc.nasa.gov/apod/ap071121.html

 

 

Expansive Comet Holmes

Credit & Copyright: Jean-Charles Cuillandre (CFHT), Hawaiian Starlight, CFHT

 

Explanation: The spherical coma of Comet Holmes has swollen to a diameter of over 1.4 million kilometers, making the tenuous, dusty cloud even bigger than the Sun. Scattering sunlight, all that dust and gas came from the comet's remarkably active nucleus, whose diameter before the late October outburst was estimated to be a mere 3.4 kilometers. In this sharp image, recorded on November 14 with the Canada-France-Hawaii Telescope, stars are easily visible right through the outer coma, while the nucleus is buried inside the condensed, bright region. The bright region of the coma seems offset from the center, consistent with the idea that a large fragment drifted away from the nucleus and disintegrated, producing the comet's spectacular outburst. Of course, more recent images of Holmes also show the bright star Mirfak (Alpha Persei) shining through as the comet sweeps slowly through the constellation Perseus.

[iNow]

She's purdie...

 

http://antwrp.gsfc.nasa.gov/apod/astropix.html

 

 

 

 

Comet Holmes from the Hubble Space Telescope

Credit: A. Dyer (Ground based image); NASA, ESA, and H. Weaver (JHU APL) (Hubble image)

 

 

Explanation: Why did Comet Holmes brighten? The unexpectedly bright Comet 17P/Holmes continues to grace northern skies as a naked-eye addition to the constellation Perseus. Any northern sky enthusiast with a dark sky, a bright curiosity, and a recent sky map should still be able to locate the comet in a few minutes. What is seen, however, is primarily the sun-light reflecting dust coma. It surrounds an iceberg nucleus too small and too faint to discern. Clues to the nearly million-fold brightness increase are therefore being sought in dramatic images of the enigmatic comet's central regions taken earlier this month by the Hubble Space Telescope. One such Hubble image, shown above, indicates a still unresolved dense central dust cloud near the nucleus, surrounded by a more complex, anisotropic coma. The Hubble images do not show any obvious fragmentation of the nucleus, however, as was seen last year in Comet Schwassman-Wachmann 3. Observers around and above the world will continue to study this unusual addition to the night sky.

 

Be sure to click the picture and visit the links offered in the explanation.

[iNow]

I didn't want to open a new thread to share this, and this particular thread has been more or less dormant so it seemed as good a place as any... but...

 

 

THIS is cool!

 

http://www.youtube.com/watch?v=RFVwo8u6SmM

 

 

It's a 30 second time-lapse movie of a coronal mass ejection spanking against a comet and ripping off much of tail in the process. A friend of mine shared it elsewhere, and I'm piggy backing on his bad ass-ossity.