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[Chicago Astronomer - Astro Joe]

Mini-Comets Approaching Earth

A cometary "string-of-pearls" will fly past Earth in May 2006 giving astronomers a fantastic view of a dying comet.

March 24, 2006: In 1995, Comet 73P/Schwassmann-Wachmann 3 did something unexpected: it fell apart. For no apparent reason, the comet's nucleus split into at least three "mini-comets" flying single file through space. Astronomers watched with interest, but the view was blurry even through large telescopes. "73P" was a hundred and fifty million miles away.

We're about to get a much closer look. In May 2006 the fragments are going to fly past Earth closer than any comet has come in more than twenty years.

"This is a rare opportunity to watch a comet in its death throes—from very close range," says Don Yeomans, head of NASA's Near Earth Object Program at JPL.

There's no danger of a collision. "Goodness, no," says Yeomans. "The closest fragment will be about six million miles away--or twenty-five times farther than the Moon." That's close without actually being scary.

The flyby is a big deal. "The Hubble Space Telescope will be watching," says Yeomans. "Also, the giant Arecibo radar in Puerto Rico will 'ping' the fragments to determine their shape and spin." Even backyard astronomers will be able to take pictures as the mini-comets file through the constellations Cygnus and Pegasus on May 12, 13 and 14.

Bonus: There could be a meteor shower, too.

This is very uncertain, indeed, forecasters consider it unlikely. But an expanding cloud of dust from the 1995 break-up of the comet could brush past Earth in May 2006 producing a display of meteors.

Astronomer Paul Wiegert at the University of Western Ontario has studied the possibility:

"We believe the cloud is expanding too slowly to reach Earth only eleven years after the break-up," he says, "but it all depends on what caused the comet to fly apart—and that we don't know."

Full story here from NASA: science.nasa.gov/headlines/y2006/24mar_73p.htm

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Excellent...perhaps we not only get to observe some fragments, but maybe a meteor show to boot!...

It will also come mighty close to my favorite nebula M57 as well... ;D

[Al Degutis]

Here are my latest attempts to image comet 73/P-C. I hosted a small
gathering in Woodstock where I was able to visually use a 20" Obsession dob. Very nice views, especially of the comet. But that's off topic.



Here's the full size comet pics from 4/23, the same 37 images stacked but processed 5 different ways:

www.skyinsight.net/DeepSkyImager/gallery/al_comets

[Chicago Astronomer - Astro Joe]

Al,

I think that is quite a cool shot of the frag comet. What was the exposure time and can you see it naked eye? You say processed five different ways...how so?

I would like to learn more of your time at the Obsession eyepiece as well.

[Chicago Astronomer - Astro Joe]

May 11th to 14th - Prime Time to Observe 73P

Comet 73P will be the closest to the Earth, on 11 to 14 May.

Fragment C of the comet should be the closest to Earth on 11 May, when it will be about 12 million km away, while fragment B will come as ‘close' as 10 million km from Earth on 14 May. Although this is the closest a comet ever approached Earth in more than twenty years even Comet Hyakutake's smallest distance was 15 million km - this is still 26 times the distance between the Earth and the Moon and therefore does not pose any threat to our planet.

If nothing else happens, at the time of closest approach, fragment B will be just visible with unaided eye by experienced observers. It should be an easy target however to observe with binoculars. If we are lucky, however, fragment B presents another outburst, becoming a magnificent sight in the night sky. On the other hand, it could just as well fade away into oblivion. But then, the main fragment C should still be visible, even possibly with the unaided eye.

Comet 73P continues to fragment and update here:
www.spacedaily.com/reports/VLT_Takes_Images_Of_Disintegrating_Comet_P73_Schwassmann_Wachmann_3.html

[Chicago Astronomer - Astro Joe]

Comet 73P/Schwassmann-Wachmann 3 Locater Chart

This nice chart from NightSkyObserver.com

More sites with charts here:

shopplaza.nl/astro/comets/comets.htm

members.leapmail.net/~ericj/comet_schwassmann_wachmann3.html

[Chicago Astronomer - Astro Joe]

Hubble Captures Comet 73P

Here is quite an interesting series of images of 73P that the Hubble took recently.

From NASA:

NASA said Thursday there is no danger that Comet 73P/Schwassmann-Wachmann 3 - or any of its many fragments - will strike Earth during its closest approach next month. To provide further reassurances, the agency has employed the Hubble Space Telescope to take high-resolution images of the approaching object, and will soon follow suit with Spitzer to observe the fragments in infrared light.

"We are very well acquainted with the trajectory of Comet 73P Schwassmann-Wachmann 3," said Don Yeomans, manager of the agency's Near-Earth Object Program, at Jet Propulsion Laboratory. "There is absolutely no danger to people on the ground or the inhabitants of the International Space Station, as the main body of the object and any pieces from the breakup will pass many millions of miles beyond the Earth."

Yeomans' pointed statement about 73P is apparently in response to vague reports on the World Wide Web that a piece of the comet will hit Earth during the flyby. Although the number of fragments has risen to nearly four dozen, he said none of them poses an impact hazard.

None of the comet's fragments will come closer than 5.5 million miles to Earth during its closest approaches between May 12 and 28 - or more than 20 times the distance between Earth and the Moon.

The main fragment, C, will pass closest to Earth on May 12 at a distance of approximately 7.3 million miles. It will be visible to small telescopes during the morning hours in the constellation Vulpecula, or the Coathanger.

73P is no stranger to astronomers, who have been observing the comet for more than 75 years. They have computed its trajectory repeatedly and have refined the level of precision over time - so 73P's orbit is well known. The real news is that Hubble's images show many more fragments than had been reported by ground-based observers.

The comet is currently comprised of a chain of more than 40 fragments, named alphabetically and stretching across several degrees on the sky. Observers have noted some dramatic brightenings among some of the fragments, which suggests they are continuing to disintegrate - some could disappear altogether.

Hubble caught two of the fragments, B and G, shortly after large outbursts in activity. Hubble also photographed fragment C, which at the time was less active. The resulting images reveal that some sort of destructive process is taking place, in which fragments are continuing to split into smaller chunks.

Hubble has found several dozen house-sized fragments trailing each main fragment. Sequential images of the B fragment, for example, taken a few days apart, suggest the chunks are pushed down the tail by outgassing from the icy, sunward-facing surfaces of the chunks, much like space-walking astronauts are propelled by their jetpacks.

Source here: www.spacedaily.com/reports/NASA_Employs_Hubble_To_Reassure_About_Comet_73P.html

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I hope we can catch it in the heart of the city...

[Kalvis]

Last night under good seeing and transparency conditions I was out on my lawn chair in the backyard around 10 p.m. with my trusty 10x50 binos handheld. My house blocks the West and a streetlight floods the Southeast, but other directions are pretty open. Around 10:30 p.m. before retiring and after my night vision got as good as it can get under such conditions I decided to look for the fragments of S-W 3. As slowly and carefully as I could I scanned the areas near both tips of Corona Borealis which was sitting high (70 degrees) in the East. Unfortunately, I couldn't find any cotton balls which would be suspected to be comet fragments.

Luckily, we've got a couple more weeks to keep on trying.

Kalvis

[Al Degutis]

I was not able to image comet 73/P conjunction with M57 because it occurred while still below my perimeter trees. I did capture some images of the comet shortly after. I've only had time to do some quick and dirty processing:



Full size images here:
www.skyinsight.net/DeepSkyImager/gallery/al_comets

M57 from the night before the conjunction (and higher in the sky away from a lot of atmospheric murk):



Full size:
www.skyinsight.net/DeepSkyImager/gallery/al_messier/M57_12min_a

[Chicago Astronomer - Astro Joe]

Al,

Nice shots of the encounter you got and good color of the nebula...

I ventured out by the Adler last night along with Chicago Astronomers John and Bill. We set up along the south side of the Adler to catch Vega rising over the lake. Although it was a clear and cool pleasent evening, the observing conditions were terrible and quite poor. Even M57 was not visible!... #confuse# . I was only able to stay for about an hour, but I wish I could have stayed longer to catch it higher in the sky...and perhaps better observing.

Here is another good shot of the fly-by from Chris Brownewell:

He says:
" Hi Joe,
Here's one for you. This was taken from Site B last night, 5-7-06. 10" Meade RCX400 @ f/5, 1 minute exposure at ISO 800, Canon 20Da."


Excellent imaging guys and thanks for sharing!...

[Al Degutis]

I've just added an animation that shows the comet (with M57) over a 12 minute period:

www.skyinsight.net/DeepSkyImager/gallery/al_comets

[stargazer]

Nice shots Al

Ive been to pooped to view, Chickens arrive this week so had to finish coop. The one night I wanted to view we had clouds. I have a Brownie Troop viewing this weekend so I will try then

[Al Degutis]

Thanks for the nice comet, Becky.

Here is one of the best images I've see so far of the conjunction:

www.buytelescopes.com/gallery/photos/8913.jpg

Wish I had that scope, that camera and those skills.

[Chicago Astronomer - Astro Joe]

Al,

That image comes from a great site that showcases extraordinary photo skills and techniques from a man named Stephan Seip. Taken from Germany, there's a certain depth and finese to them that I haven't seen anywhere else.

You can find the site here: www.photomeeting.de/astromeeting/index_news.htm

Good stuff!...

[Chicago Astronomer - Astro Joe]

Sliding on previous debris trails

This infrared image from NASA's Spitzer Space Telescope shows the broken Comet 73P/Schwassman-Wachmann 3 skimming along a trail of debris left during its multiple trips around the sun. The flame-like objects are the comet's fragments and their tails, while the dusty comet trail is the line bridging the fragments.

Comet 73P /Schwassman-Wachmann 3 began to splinter apart in 1995 during one of its voyages around the sweltering sun. Since then, the comet has continued to disintegrate into dozens of fragments, at least 36 of which can be seen here. Astronomers believe the icy comet cracked due the thermal stress from the sun.

The Spitzer image provides the best look yet at the trail of debris left in the comet's wake after its 1995 breakup. The observatory's infrared eyes were able to see the dusty comet bits and pieces, which are warmed by sunlight and glow at infrared wavelengths. This comet debris ranges in size from pebbles to large boulders. When Earth passes near this rocky trail every year, the comet rubble burns up in our atmosphere, lighting up the sky in meteor showers. In 2022, Earth is expected to cross close to the comet's trail, producing a noticeable meteor shower.

Astronomers are studying the Spitzer image for clues to the comet's composition and how it fell apart. Like NASA's Deep Impact experiment, in which a probe smashed into comet Tempel 1, the cracked Comet 73P/Schwassman-Wachmann 3 provides a perfect laboratory for studying the pristine interior of a comet.

This image was taken from May 4 to May 6 by Spitzer's Multiband Imaging Photometer, using its 24-micron wavelength channel.

Source from NASA: www.spitzer.caltech.edu/Media/releases/ssc2006-13/ssc2006-13a.shtml?msource=07506&tr=y&auid=1659074

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