[meteorite-list] Asteroid 2011 AG5 - A Reality Check

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Wed, 29 Feb 2012 14:53:03 -0800 (PST)
Message-ID: <201202292253.q1TMr3FX018118_at_zagami.jpl.nasa.gov>

http://www.jpl.nasa.gov/news/news.cfm?release=2012-051

Asteroid 2011 AG5 - A Reality Check
Jet Propulsion Laboratory
February 28, 2012

Asteroid 2011 AG5 has been receiving a lot of attention lately because
of a very unlikely scenario which would place it on an
Earth-interception course 28 years from now. Here is a scientific
reality check of this relatively nondescript space rock which is
currently ranked a "1" on the 1 to 10 _Torino Impact Hazard Scale
<http://neo.jpl.nasa.gov/torino_scale.html>

As of Feb. 26, 2012, asteroid 2011 AG5 is one of 8,744 near-Earth
objects that have been discovered. It is approximately 460 feet (140
meters) in size and its orbit carries it as far out as beyond Mars'
orbit and as close to the sun as halfway between Earth and Venus. It
was discovered on Jan. 8, 2011, by astronomers using a 60-inch
Cassegrain reflector telescope located at the summit of Mount Lemmon in
the Catalina Mountains north of Tucson, Arizona.

Due to its current location in the daytime sky, observations of 2011 AG5
cannot be made by Earth-based telescopes, so its orbit has not yet been
determined to a level where scientists can confidently project its
location decades into the future. But that day is coming.

"In September 2013, we have the opportunity to make additional
observations of 2011 AG5 when it comes within 91 million miles (147
million kilometers) of Earth," said Don Yeomans, manager of NASA's
Near-Earth Object Program Office at the Jet Propulsion Laboratory in
Pasadena, Calif. "It will be an opportunity to observe this space rock
and further refine its orbit. Because of the extreme rarity of an impact
by a near-Earth asteroid of this size, I fully expect we will be able to
significantly reduce or rule out entirely any impact probability for the
foreseeable future." Even better observations will be possible in late 2015.

2011 AG5 will next be near Earth in February of 2023 when it will pass
the planet no closer than about 1 million miles (1.6 million
kilometers). In 2028, the asteroid will again be in the area, coming no
closer than about 10.4 million miles (16.7 million kilometers). The
Near-Earth Object Program Office states the Earth's gravitational
influence on the space rock during these flybys has the potential to
place the space rock on an impact course for Feb. 5, 2040, but this has
very unlikely odds of occurring at 1-in-625.

"Again, it is important to note that with additional observations next
year the odds will change and we expect them to change in Earth's
favor," said Yeomans.

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 determines
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, Ca.
agle at jpl.nasa.gov

2012-051
Received on Wed 29 Feb 2012 05:53:03 PM PST