Friday, November 09, 2007

Friday Fun: Watch for Comet Holmes this weekend!

Click on the title to this post to read an entry from Sky and Telescope online about locating (and viewing) this weekend, the newly bright Comet Holmes that is especially well-viewed this weekend. In October, this comet which had been dark and nearly forgotten suddenly erupted gas and particles that caught the sunlight, becoming bright enough to see with the unaided eye.

Amateur astronomers the world over have been stunned and amazed by the weirdest new object to appear in the sky in memory. And it's one of the brightest, too — it's easy to spot with your eyes alone if you know where to look.

Observers worldwide had no trouble spotting Comet Holmes through the full moonlight on the evening of October 25, 2007. On October 24th, periodic Comet Holmes (17P) brightened dramatically — by nearly a million times — virtually overnight. For no apparent reason, the comet erupted from a very dim magnitude 17 to about magnitude 2½. Within a day its starlike nucleus had expanded into a perfectly round, bright little disk visible in binoculars and telescopes. It looked like no comet ever seen.

Its startling outburst, however, has a precedent. The comet was also in a major eruption 115 years ago, in November 1892, when English amateur Edwin Holmes was the first to spot it. It reached 4th or 5th magnitude, faded in the following weeks, and then underwent a second eruption 2½ months after the first.
Click here for the full story from Sky & Telescope which is being kept updated. They have nice images but the links they provide don't go anywhere. You can see some copyrighted images here from a number of observatories and amateur skywatchers, along with a detailed history of its appearances. The comet does not look like I expected, since you really can't see much of a tail. The text comments that you can see faint blue gas streamers in some images, creating a tail, but to me, it looks like an extraordinary star. The Los Angeles Times explains
Scientists speculate the comet has exploded because there are sinkholes in its nucleus, giving it a honeycomb-like structure. The collapse exposed comet ice to the sun, which transformed the ice into gas.

"What comets do when they are near the sun is very unpredictable," Lewis said. "We expect to see a coma cloud and a tail, but this is more like an explosion, and we are seeing the bubble of gas and dust as it expands away from the center of the blast."

Image is Comet Holmes shot from Coyote Canyon in Anza Borrego Desert State Park by Don Barletti for the Los Angeles Times article here.

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