[meteorite-list] Reports of Meteorite Strike in Nicaragua and Update on Asteroid 2014 RC

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Mon, 8 Sep 2014 12:42:26 -0700 (PDT)
Message-ID: <201409081942.s88JgQNA017428_at_zagami.jpl.nasa.gov>

http://neo.jpl.nasa.gov/news/news185.html

Reports of Meteorite Strike in Nicaragua and Update on Asteroid 2014 RC
NASA/JPL Near-Earth Object Program Office
September 8, 2014

Reports in the media over the weekend that a small meteorite impacted in
Nicaragua have yet to be confirmed. A loud explosion was heard near
Managua's international airport Saturday night, and photos of a 24-meter
(80-foot) crater have been circulated. As yet, no eyewitness accounts or
imagery have come to light of the fireball flash or debris trail that is
typically associated with a meteor of the size required to produce such
a crater. Since the explosion in Nicaragua occurred a full 13 hours
before the close passage of asteroid 2014 RC, these two events are
unrelated.

As predicted, the small asteroid 2014 RC flew safely past the Earth at
18:01 UT (2:01 pm EDT, 11:01 am PDT) on September 7 at a distance of
33,550 km (20,800 miles) above the Earth's surface. Astronomers around
the world took the opportunity to observe this fairly rare event, and
learned that the asteroid is about 12 meters (40 feet) in size and is
spinning very rapidly.

R. P. Binzel, D. Polishook (MIT) and S. J. Bus (Univ. Hawaii) observed
2014 RC from NASA's Infrared Telescope Facility (IRTF) on Sept. 6 in
near-infrared wavelengths. From their spectra, they conclude that the
asteroid belongs to the "Sq-class", which has an average albedo
(reflectivity) of 24%. Based on the available measurements of the
asteroid' intrinsic brightness, they conclude that 2014 RC is about 12
meters (40 feet) across, roughly the size of a school bus. This puts
2014 RC at about one-half the size of the February 15, 2013 Chelyabinsk
impactor.

Lance Benner and Marina Brozovic, Jet Propulsion Laboratory, meanwhile,
reported that radar observations of 2014 RC taken at the Goldstone site
in southern California on September 6-7 were weaker than expected due to
an extreme Doppler broadening of the radar echoes. If the 12-meter size
is adopted and an equatorial radar view is assumed, then the radar
measurements indicate an extremely fast rotation rate of at least
several revolutions per minute.

Following up on this preliminary result, A. Thirouin, B. Skiff, and N.
Moskovitz (Lowell Observatory) analyzed the brightness variations of
2014 RC across multiple nights using Lowell Observatory' 1.1m Hall
telescope, Lowell's 4.3m Discovery Channel Telescope and NASA's IRTF. A
subset of these images have been combined into an movie which can be
downloaded here:

http://www2.lowell.edu/users/nmosko/2014RC_flyby.gif

These data indicate a best fit rotation period of about 15.8 seconds,
and a low light curve amplitude of ~0.1 magnitude. This is the fastest
rotating asteroid observed to date, roughly 50% faster than the previous
record holder.
Received on Mon 08 Sep 2014 03:42:26 PM PDT