On 25 May 2001, the asteroid 1999 KW4 was traveling at about 4.8 million km from us. This body belongs to the important class of Aten asteroids (having their semimajor axes inside the Earth's orbit). Its period is the shortest we know, with the exception of the planet Mercury: 188 days. We estimate its diameter to be 2, 4 km. It was discovered on May 20, 1999 by LINEAR, a dedicated searching program, hunting for Near Earth Objects (NEOs). The picture above is composed by 37, 6 sec long, CCD exposures, taken at Bellatrix Observatory by Gianluca Masi, each of them 20 min apart. The body is well visible, moving very fast. The first frame (low, on the left) was captured on May 27 at 22:27.16 UT.
