[meteorite-list] Asteroid 2012 DA14 To Pass Very Close to the Earth on February 15, 2013

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Fri, 1 Feb 2013 13:32:03 -0800 (PST)
Message-ID: <201302012132.r11LW3wm025897_at_zagami.jpl.nasa.gov>

http://neo.jpl.nasa.gov/news/news177.html

Asteroid 2012 DA14 To Pass Very Close to the Earth on February 15, 2013
Paul Chodas and Don Yeomans
NASA/JPL Near-Earth Object Program Office
February 1, 2013

The small near-Earth asteroid 2012 DA14 will pass very close to the
Earth on February 15, 2013, so close that it will pass inside the ring
of geosynchronous weather and communications satellites. NASA's NEO
Program Office can accurately predict the asteroid's path with the
observations obtained, and it is therefore known that there is no chance
that the asteroid might be on a collision course with the Earth.
Nevertheless, the flyby will provide a unique opportunity for
researchers to study a near-Earth object up close.

Asteroid 2012 DA14 will be closest to Earth on February 15, 2013 at
about 19:24 GMT (2:24 p.m. EST or 11:24 a.m. PST), when it will be at a
distance of about 27,700 kilometers (17,200 miles) above the Earth's
surface. This is so close that the asteroid will actually pass inside
the ring of geosynchronous satellites, which is located about 35,800
kilometers (22,200 miles) above the equator, but still well above the
vast majority of satellites, including the International Space Station.
At its closest, the asteroid will be only about 1/13th of the distance
to the Moon. The asteroid will fly by our planet quite rapidly, as a
speed of of about 7.8 kilometers/second (17,400 miles/hour) in a
south-to-north direction with respect to the Earth.

Even though 2012 DA14 is coming remarkably close, it will still only
appear as a point of light in the biggest of optical telescopes because
of its small size. Based on its brightness, astronomers estimate that it
is only about 45 meters (150 feet) across. It will brighten only to
magnitude 7.5, too faint to be seen with the naked eye but easily
visible in a good set of binoculars or a small telescope. The best
viewing location for the closest approach will be Indonesia, from which
the asteroid will be seen to move at a rate of almost 1 degree per
minute against the star background. Eastern Europe, Asia and Australia
are also well situated to see the asteroid around its closest approach.
But by the time the Earth rotates enough for observers in the
continental United States to have a chance to see the asteroid, it will
have receded and faded to about 11th magnitude. Radar astronomers plan
to take images of the asteroid about 8 hours after closest approach
using the Goldstone antenna.

2012 DA14 has not been in our catalogs for very long -- it was
discovered in February 2012 by astronomers at the La Sagra Sky Survey
program in southern Spain and reported to the Minor Planet Center. The
asteroid had just made a fairly distant passage by the Earth, about 7
times farther than the distance to the Moon when it was first detected
by the Spanish group. Since 2012 DA14's orbital period around the Sun
has been about 368 days, which is very similar to the Earth's, the
asteroid made a series of annual close approaches, this year's being the
closest. But this encounter will shorten 2012 DA14's orbital period to
about 317 days, changing its orbital class from Apollo to Aten, and its
future close approaches will follow a different pattern. The close
approach this year is the closest the asteroid will come for at least 3
decades.

This passage of 2012 DA14 by the Earth is a record close approach for a
known object of this size. A few other known asteroids have flown by the
Earth even closer, but those asteroids were smaller. On average, we
expect an object of this size to get this close to the Earth about once
every 40 years. An actual Earth collision by an object of this size
would be expected much less frequently, about once every 1200 years on
average.

The diagram below shows the south-to-north trajectory of 2012 DA14
passing safely above the Earth's surface but well within the ring of
geosynchronous satellites.

[Diagram]
Received on Fri 01 Feb 2013 04:32:03 PM PST