Asteroid is due to make flyby of Earth

An asteroid rarely gets close enough to Earth to be bright enough to see with a backyard telescope or binoculars, but islanders might see one tomorrow night, said University of Hawaii astronomer David Tholen.

The closest approach of asteroid 2007 TU24 to Earth will be about 334,000 miles, about 1.4 times the distance of Earth to the moon, at 10:46 p.m. tomorrow, "for 27 seconds," he said. "It will be far in the northern part of the sky and moving very rapidly."

At its brightest, it may be out of range for typical binoculars, he said. But observers with a small telescope should be able to see it, he said. "It will be easy to identify just by pointing and waiting for something to move. It won't take very long to notice the motion."

The asteroid is estimated to be 500 to 2,000 feet long. It was discovered last October by the Catalina Sky Survey in Arizona.

It won't affect the Earth, said Don Yeomans, manager of the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory.

The next time an asteroid about the same size will approach that close to Earth will be in 2027, according to NASA. But Tholen said, "Between now and 2027, we will probably find something new that we don't know about that will come closer."

Tracking potentially dangerous near-Earth asteroids and comets is one of the things the Panoramic Survey Telescope and Rapid Response System, known as Pan-STARRS, will do, he pointed out.

A prototype of Pan-STARRS is being developed on Haleakala, Maui, and Mauna Kea on the Big Island has been proposed as the site for a permanent system.

Another asteroid, 2007 WD5, is expected to pass about 16,000 miles from Mars next week.

"We have bit of connection to that," Tholen said. His research team, including Fabrizio Bernardi and Marco Micheli, was the last to observe the WD5 on Jan. 8 and 9, using the UH 88-inch telescope on Mauna Kea, he said.

The probability of impact with Mars was high, so they pushed for additional observations and got them, he said.