[meteorite-list] Nine Radar Images of Asteroid 2007 PA8
From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 26 Nov 2012 15:44:58 -0800 (PST)
Nine Radar Images of Asteroid 2007 PA8
Jet Propulsion Laboratory
November 26, 2012
A collage shows nine radar images of near-Earth asteroid 2007 PA8 that
were obtained between Oct. 31 and Nov. 13, 2012, with data collected by
NASA's 230-foot-wide (70-meter) Deep Space Network antenna at Goldstone,
Calif. On Nov. 5 at 8:42 a.m. PST (11:42 a.m. EST/16:42 UTC), the object
came about 4 million miles (6.5 million kilometers) from Earth, or 17
times the distance between Earth and the moon.
The images of 2007 PA8 reveal possible craters, boulders, an irregular,
asymmetric shape, and very slow rotation. The asteroid measures
approximately one mile wide (about 1.6 kilometers).
Each panel shows one image per day, and all of them are oriented so
rotation is counterclockwise. Each image is shown at the same scale and
covers 1.1 miles (1.7 kilometers) from top to bottom. The resolution of
the images varies from day to day as the asteroid's distance changed.
The images achieve resolutions as fine as 12 feet (3.75 meters) per
pixel on Nov. 5 and 6, when the asteroid was closest. The resolution was
25 feet (7.5 meters) per pixel on Nov. 2, 3 and 8, and 62 feet (18.75
meters) per pixel on Oct. 31 and Nov. 11 to 13.
New radar measurements of 2007 PA8's distance and line-of-sight velocity
refined calculations of its orbit about the sun, enabling reliable
computation of the asteroid's motion for the next 632 years. 2007 PA8 is
not a threat to Earth. The 2012 flyby was the closest since 1880. The
next flyby with Earth closer than the one that occurred this year will
be in 2488, when the asteroid will approach no closer than 3.6 million
miles (5.8 million kilometers).
NASA detects, tracks and characterizes asteroids and comets passing
close to Earth using both ground- and space-based telescopes. The
Near-Earth Object Observations Program, commonly called "Spaceguard,"
discovers these objects, characterizes a subset of them, and plots their
orbits to determine if any could be potentially hazardous to our planet.
JPL manages the Near-Earth Object Program Office for NASA's Science
Mission Directorate in Washington. JPL is a division of the California
Institute of Technology in Pasadena.
DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle at jpl.nasa.gov
Received on Mon 26 Nov 2012 06:44:58 PM PST