Today's Image

This is not Comet ISON, but it could be

Posted by
Deborah Byrd
and
November 26, 2013
View larger. | This is not Comet ISON. It's Comet Schwassmann-Wachmann 3, another sungrazing comet, which disintegrated on its pass near the sun in 2006. Image via Bad Astronomy blog via Hubble Space Telescope.
View larger. | This is not Comet ISON. It’s Comet Schwassmann-Wachmann 3, another comet, which was observed to be disintegrated on its pass near the sun in 2006. Image via Bad Astronomy blog via Hubble Space Telescope.

Has Comet ISON disintegrated? Rumors are flying in the astronomical community. Read more about ISON’s possible disintegration here.

This isn’t Comet ISON. It’s Comet Schwassmann-Wachmann 3, a periodic comet that orbits the sun on a vastly shorter timeframe than ISON, only 5.3 years. This comet is in the process of disintegrating. It was observed to break into fragments as it entered the inner part of the solar system in 2006, as it encountered the sun’s fierce heat, much as ISON is encountering it now.

This comet brings with it some good news, however. Comet Schwassmann-Wachmann 3 is a parent body of a meteor shower – the Tau Herculids – seen from Earth. If Comet ISON breaks up, will we see the meteor shower predicted by some for January 2014?

Schwassmann–Wachmann was estimated to have an original core diameter of 1,100 meters, by the way. What is ISON’s core diameter? Totally unknown, but it might be comparable.

Schwassman-Wachmann3-B-HST

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November 26, 2013
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Deborah Byrd

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About the Author:
Deborah Byrd (asteroid 3505 Byrd) helps edit EarthSky.org and is a frequent host of EarthSky videos. Deborah created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Prior to that, she had worked for the University of Texas McDonald Observatory since 1976, and created and produced their Star Date radio series. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named in her honor in 1990, a Public Service Award from the National Science Board in 2003, and the Education Prize from the American Astronomical Society in 2020. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.

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