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Saturday, December 17, 2011


Comet Lovejoy gets its Tail Back

Left Image: C/2011 W3 Lovejoy in SOHO C3 (16 December UT). Right Image: C/2011 W3 Lovejoy in STEREO beacon (low resolution) images in H1A (16 December, far right). Click to embiggen. Image credit NASA/SOHO and NASA/SECCHI. (earlier images here and here)

Comet Lovejoy is getting its tail back. If you embiggen the SOHO image you can see the old tail dissipating on the other side of the Sun. Without doing serious astrometery (for which I need the hir res versions of the STEREO images which will come later), my impression is that the comet is brighter.

I'm going to quote Karl Battams in full here because I'm too lazy he says it best.
1700UT: I'm going to hope he doesn't mind me doing this, and steal a quote here from highly-respected astronomer John Bortle: "I trust that most here appreciate that we are witnessing one of the most extraordinary events in cometary history."

Let that sink in a minute, because he is absolutely correct. This is not simply "news-worthy", or even "of great interest"; this is indeed competely extraordinary.

Sungrazing comets, particularly those of the Kreutz-group, have fascinated astronomers for decades, and no doubt terrified civilizations of the past, as their orbits hurled them through the solar atmosphere, resulting in a brilliant daytime illumination of these enormous 'dirty snowballs'. There is arguably no other object in the solar system that goes through such an intense experience as one of these comets. For days now we have been witness to such a beautiful object racing through the STEREO, SOHO and now SDO and PROBA images, blasting through the solar corona, and miraculously re-emerging, albeit with much less of a tail than it started with. And whereas sungrazers of the past have been lost at least temporarily, if not permanently, in the Sun's glare, thanks to an amazing fleet of sun-watching spacecraft we have now been enthralled by this entire passage without a single hour passing by unwitnessed. Purely for the spectacle of the event, and the way it has unfolded before our eyes over the internet, this comet has sealed its place in the history books.

But there is so much more to this than just the spectacle. We have already obtained unprecedented scientific data from five different spacecraft, and I'm very optimistic that over the coming days we will get to add a sixth spacecraft to that list when Hinode analyze their data. The result is an almost overwhelming catalog of visual, narrow-band filtered, extreme ultraviolet, and spectroscopic data of a comet experiencing the most extreme environment the solar system has to offer. We will likely learn about its mass, its physical size, its composition, the size of its dust and dust production rates, and so much more. Objects like this can also provide us with a tremendous amount of information about the solar wind and conditions in the solar corona, which in turn allows us to gain more understanding of the Sun as a driver of "Space Weather" at Earth (it's one of the reasons my group is interested in sungrazing comets).

So I could not agree more with John, and I hope that all of you who are watching these movies are indeed appreciative of just how incredible this has been!

Now head over to Karl's site and see the latest amazing imagery.

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