[meteorite-list] Fast-Rotating Asteroid Winks For Astronomer's Camera (Asteroid 2011 GP59)

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu, 14 Apr 2011 12:41:21 -0700 (PDT)
Message-ID: <201104141941.p3EJfLkI017226_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2011-118

Fast-Rotating Asteroid Winks For Astronomer's Camera
Jet Propulsion Laboratory
April 14, 2011

Video imaging of newly discovered asteroid 2011 GP59 shows the object
appearing to blink on and off about once every four minutes.

Amateur astronomers, including Nick James of Chelmsford, Essex, England,
have captured video of the interesting object. James generated this
video of GP59 on the night of Monday, April 11. The video, captured with
an 11-inch Schmidt-Cassegrain telescope, is a compilation of 137
individual frames, each requiring 30 seconds of exposure. At the time,
the asteroid was approximately 3,356,000 kilometers (2,081,000 mile)
distant. Since then, the space rock has become something of a darling of
the amateur astronomy community, with many videos available. (Here is
one recent posting: http://www.youtube.com/watch?v=O7wsAZNr56E )

"Usually, when we see an asteroid strobe on and off like that, it means
that the body is elongated and we are viewing it broadside along its
long axis first, and then on its narrow end as it rotates ," said Don
Yeomans, manager of NASA's Near-Earth Object Program Office at the Jet
Propulsion Laboratory in Pasadena, Calif. "GP59 is approximately 50
meters [240 feet] long, and we think its period of rotation is about
seven-and-a-half minutes. This makes the object's brightness change
every four minutes or so."

2011 GP59 was discovered the night of April 8/9 by astronomers with the
Observatorio Astronomico de Mallorca in Andalusia, Spain. It will make
its closest approach to Earth on April 15 at 19:09 UTC (12:09 p.m. PDT)
at a distance just beyond the moon's orbit - about 533,000 kilometers
(331,000 miles).

"Although newly discovered, the near-term orbital location of asteroid
2011 GP59 can be accurately plotted," said Yeomans. "There is no
possibility of the small space rock entering Earth's atmosphere during
this pass or for the foreseeable future."

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.

More information about asteroids and near-Earth objects is at:
http://www.jpl.nasa.gov/asteroidwatch .

DC Agle (818) 393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle at jpl.nasa.gov

2011-118
Received on Thu 14 Apr 2011 03:41:21 PM PDT