May 30, 2013: Approaching asteroid 1998 QE2 has a moon. Researchers found it in a sequence of radar images obtained by the 70-meter Deep Space Network antenna at Goldstone, Calif., on the evening of May 29th (May 30th Universal Time) when the asteroid was about 6 million kilometers from Earth.
The preliminary estimate for the size of the asteroid’s satellite is approximately 600 meters wide. The asteroid itself is approximately 2.7 kilometers in diameter and has a rotation period of less than four hours.
First radar images of asteroid 1998 QE2 were obtained when the asteroid was about 3.75 million miles (6 million kilometers) from Earth. The radar collage covers a little bit more than two hours. Image credit: NASA/JPL-Caltech/GSSR
The radar observations were led by scientist Marina Brozovic of NASA’s Jet Propulsion Laboratory in Pasadena, CA.
These findings show that 1998 QE2 is a binary asteroid. In the near-Earth population, about 16 percent of asteroids that are about 200 meters or larger are binary or triple systems Also revealed in the radar imagery of 1998 QE2 are several dark surface features that suggest large concavities.
The resolution of these initial images of 1998 QE2 is approximately 75 meters per pixel. Resolution is expected to increase in the coming days as more data become available. Between May 30 and June 9, radar astronomers using the Deep Space Network antenna at Goldstone, Calif., and the Arecibo Observatory in Puerto Rico, will perform an extensive campaign of observations on asteroid 1998 QE2. The two telescopes have complementary imaging capabilities that will enable astronomers to learn as much as possible about the asteroid during its brief visit near Earth.