A newly discovered comet has appeared in the sky, and astronomers say it may become the brightest one in two decades. It is already so bright that experts are betting that it will soon be easily visible to the naked eye in places where the sky is relatively unpolluted by outdoor lighting.
The comet, C/1996 b2 (Hya-ku-take), named for its discoverer, Yuji Hyakutake, caught astronomers by surprise; its existence was unknown until Hyakutake, an amateur comet hunter in Japan, spotted it through powerful binoculars on Jan. 30. Since then, the comet has steadily brightened as it speeds toward the Sun, sun, and it has developed tails of ionized gas and dust that are becoming visible to the unaided eye.Many observatories around the world are preparing to study the comet over the next weeks and months. Experts advise amateur stargazers to seek sites at least 60 miles from large cities for the best views of the comet.
Planetary astronomers have so often guessed wrong in their attempts to predict the brightness of comets that they have come to couch all their forecasts in caveats. But a consensus is emerging that Hyakutake's comet may be the brightest comet since the West comet in 1976.
The comet's orbit has been calculated, and it will make its closest approach to the Earth on March 25, at a distance of 9.3 million miles, about one-tenth the distance between the Earth and the Sun. If it continues to brighten at its present rate, the comet could reach about the same overall brightness as the star Vega, said Dr. Brian G. Marsden of the Smithsonian Astrophysical Observatory in Cambridge, Mass.
Unfortunately, this amount of light will be spread over the entire comet, including not only its small nucleus but its enormous coma and tail. Since Hyakutake's comet is likely to cover a part of the sky several times larger than the full Moon, its diffused light will seem dimmer than the same amount of light coming from a single point like Vega.
The magazine Sky and Telescope reported that the comet should become easy to see in midnorthern latitudes starting next Thursday at about 11 p.m. Eastern Time.
"Face east, look high, and spot the brightest star in this part of the sky," the magazine advised. "The star is Arcturus; you can't miss it. Hold your fist out to arm's length in front of you. Sighting past it, look one fist width below Arcturus. That's the location of the comet's head."
The comet will probably reach its peak brightness between March 24 and March 26.