The Wait is Over for Another Comet

Most of us remember the two years in a row when we were treated with naked eye comets Hyakutake and Hale-Bopp. For those confused over the term "naked eye," we mean that you can see the object without any aid such as binoculars or telescope. It is a rare event that such comets come along and having had two spectacular comets so close together has made us yearn for more. Well the wait is over, and we have a new visitor to our corner of the solar system.

The comet was co-discovered this year on February first by Kaoru Ikeya of Japan and Daqing Zhang of China. The comet is named Ikeya-Zhang, after it's discoverers. Yes, if you thought Hyakutake was a mouthful.....! The comet has been increasing in brightness over the past few weeks and has finally reached naked eye status, though it is not as yet as bright as our former visitors.

Comets are the exotics of the Solar System. Though they've been aptly called dirty snowballs, they are fascinating objects. Composed mostly of gasses and icy material mixed with dust and some rocky material, they have also been known to carry organic materials, perhaps the building blocks of life itself. Comets are ancient, as old as the beginnings of the solar system, leftover debris from the planet making processes.

For the next few weeks, you can see the comet in dark skies for a few hours after sunset, just above the western horizon. If your skies are troubled by light pollution, you may not be able to see it at all, or you might see it with binoculars, depending on how bad the light pollution is.

What also makes this comet interesting is that it may have visited us previously. According to Brian Marsden of the Smithsonian Astrophysical Observatory, this comet shares a similar orbit with a comet which last visited in 1661 called C/1661 C1. If this is true, it marks an astronomical first. This would be the first return of a long period comet (long period comets have orbits of over 200 years.)

When we speak of a comet's orbit, we refer to the path it takes through the solar system. The planets all orbit the Sun in roughly the same plane, in elliptical (nearly circular) orbits. Comets travel roughly in two groups, the inner, short period comets, which circle the Sun and travel out to somewhere around the asteroid belt and back. Long period comets travel to the very outback of the Solar System, some, far beyond Pluto to an area called the Oort Comet Cloud.

Long period comets take over 200 years to make one trip around the Sun, but some take much longer, tens of thousands of years or more. That is why it is rare that we see a long period comet more than once.

The best views of Comet Ikeya-Zhang will be toward mid-April when the comet moves to the pre-dawn eastern skies. How bright will it get? Well that's the question. Comets are woefully unpredictable, especially ones we are not familiar with. The comet does show a high gas-to-dust ratio which usually means the comet will brighten quickly, as it has done. So far, the way the comet has behaved it looks very promising for April viewing as it should be brighter than it is now. Try to get a glimpse both evening and morning and compare the views. Happy comet-gazing!


Copyright © 2002 Kathy A. Miles and Charles F. Peters II