An asteroid that went lost for 89 years has been found, an astronomer said this week.
In observations made early this month, astronomer Jeff Larsen and his colleagues at the Spacewatch program at Kitt Peak, Arizona, noticed an asteroid with unusual motion.
Gareth Williams, deputy director of the Minor Planet Center in Cambridge, Massachusetts, later looked over the data and realized the astronomers had found the missing object, called 719 Albert.
Albert is the last numbered minor planet that had been lost but is now found. In 1801, astronomers started numbering asteroids and related sky objects in an effort to keep track of them. Albert was discovered in 1911 by Johann Palisa, an astronomer at the Vienna Observatory using a 27-inch telescope.
Over the years, most numbered objects have been relocated. But as recently as 20 years ago, a couple dozen objects still remained lost. Williams and other astronomers slowly whittled that list down to one -- 719 Albert. Nowadays, astronomers rely on computers to scan telescope images and calculate the orbits of asteroids and comets. This is easier than staring constantly through a telescope.
Still, Albert was elusive -- it is very faint and therefore went unobserved for decades. But the Spacewatch program, although it surveys only a small swatch of the sky, has a powerful telescope that can detect the most dim asteroids. Marsden guessed that Albert is about 2 miles across.
Williams was about to publish a report on the new object earlier this month when he noticed the object's strange orbit.
"He looked at the orbit and said, 'Ah ha. That looks like the orbit of Albert,'" Marsden said. "Then he looked into it further and spent some time linking together the observations in 1911 and the ones in 2000, which was quite a complicated thing to do. The 1911 observations aren't all that good and the 2000 observations aren't all that extensive."
Asteroid Albert rounds the sun every 4.2 years and will approach Earth in September 2001, giving astronomers a great opportunity to collect more data on it.
But it's hardly a "deep impact" candidate. It will likely come within 26 million miles (41.8 million kilometers), said Benny Peiser, a researcher at Liverpool John Moores University who publishes a newsletter on Earth-approaching asteroids and comets. That's about half the distance to Mars.
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