ZHU-BALAM COMET WILL BE VISABLE AGAIN IN 66,000 YEARS

Sharp-eyed Balam co-discovers comet

BY MIKE McNENEY

It was no ordinary night last June 8 at the Dominion Astrophysical Observatory in Saanich when UVic Astronomy research associate Dave Balam was observing a group of asteroids spotted a few days earlier by astronomers in China.

Balam was doing routine follow-up observations when he noticed something peculiar about one of the supposed asteroids&emdash;it had a very faint tail trailing from its end. After 22 years in astronomy, Balam had identified his first comet.

"I've always been an asteroid magnet and had almost given up on ever discovering a comet," said Balam. "Others always seemed to have had all the luck."

But official recognition of Balam's discovery wouldn't come from the International Astronomical Union until Jan. 23, when a bulletin released by the IAU announced that the comet would indeed be named for him and his Chinese counterpart, Gin Zhu, the leader of a team of astronomers at the Purple Mountain Observatory 250 kilometres from Beijing.

The sightings by both Zhu and Balam had placed the IAU committee responsible for officially naming comets in a predicament. If a comet is identified by a second astronomer after the original images are recorded by someone else, who should be given credit for its discovery? The IAU wrestled with the question for some 15 weeks before deciding to give credit to both. In this case, the comet first spotted last June will be known as Comet C/1997 L1 (Zhu-Balam).

Balam was surprised and delighted when he heard news of the IAU's decision from Dr. Jim Hesser of the Dominion Astrophysical Observatory in Saanich, where Balam had been working with DAO's Plaskett Telescope when he spotted the comet.

Discovering a comet is a real coup. Only about eight or 10 new comets are discovered each year and many people, particularly in Japan where a comet-naming is considered a great family honour, spend endless hours searching the skies for new comets.

Balam&emdash;who dedicates most of his observing time to tracking asteroids on potential collision courses with the earth&emdash;admits his discovery was a lucky stroke and credits the powerful Plaskett Telescope for helping him spot the comet.

The Zhu-Balam comet is non-periodic, meaning the 10 kilometre-wide ball of ice and dust won't be visible again for 66,000 years. Balam and Zhu have never met, but like many sky-watchers around the world, frequently share information electronically.

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