In December 2018, the proximity of the great asteroid 2003 SD220, near Earth, provided
astronomers an excellent opportunity to obtain detailed images of surface radar
and shape the object and improve understanding of its orbit.
the asteroid will fly safely across the Earth on Saturday, December 22, at a distance of about
1.8 million miles (2.9 million kilometers).
This will be the
closest approach to the asteroid in more than 400 years and the closest approach to 2070, when
the asteroid will safely approach Earth a little closer.
an asteroid with a length of at least one mile (1.6 km) and a similar shape
to the exposed part of a hippopotamus wading in a river. They were obtained
December 15-17, coordinating observations with NASA's 70-meter antenna
in the Deep Space Communications Complex of Goldstone, California, the National Science Foundation
Green Bank Telescope 330 feet (100 meters) in West Virginia and the Arecibo Observatory
Antenna of 305 meters in Puerto Rico.
The Green Bank Telescope was the receiver of the powerful microwave signals transmitted by Goldstone
or the Arecibo planetary radar funded by NASA in what is known as a "bistatic
radar configuration. "Using a telescope to transmit and another to receive
can render considerably more detail than a telescope, and it is an invaluable
technique to obtain asteroid radar images that are slowly approaching, spinning slowly
Radar images reach an unprecedented level of detail and are comparable to
obtained from a flyby of spacecraft, "said Lance Benner of Jet Propulsion
Laboratory in Pasadena, Calif., And the lead scientist
of Goldstone. "The most visible surface feature is a prominent crest
which appears to partially involve the asteroid near one end. The mountain range extends
about 330 feet [100 meters] above the surrounding terrain. Numerous little bright
spots are visible in the data and may be reflections of boulders. The images also
show a set of dark, circular features near the right edge, which may be craters. "
images confirm what was seen in previous measurements "light curve" of
reflected asteroid sunlight and radar images by Arecibo: 2003
The SD220 has an extremely slow rotation period of approximately 12 days. Also have what
seems to be a complex spin, something analogous to poorly played football. Known
like rotation of the "non-main axis," is unusual among asteroids near Earth,
most turn on the smallest axis.
resolutions as thin as 12 feet (3.7 meters) per pixel, the detail of these images is
20 times more than that obtained during the previous approach of the asteroid
to Earth three years ago, which was at a greater distance. The new radar data
provide important constraints on the density distribution of the interior of the asteroid
– information available on very few near-Earth asteroids.
year, with our knowledge about the slow rotation of the 2003 SD220, we were able to plan
a large sequence of radar images using the largest single dish radio telescopes
in the country, "said Patrick Taylor, senior scientist at Universities Space
Research Association (USRA) at the Lunar and Planetary Institute (LPI) in
new details that we discovered, until the 2003 SD220 geology, let's leave
reconstruct its shape and state of rotation, as was done with Bennu, the target of
OSIRIS-REx mission, "said Edgard Rivera-Valentin, USRA scientist at LPI."
reconstruction allows us to better understand how these small bodies
has evolved over time. "
Taylor led the bi-static radar observations with the Green Bank Observatory, home of
the Green Bank Telescope, the largest fully orientable radio telescope in the world. Rivera-Valentín will be leading the way
reconstruction of SD220 2003 and led the observations of the Arecibo Observatory.
2003 The SD220 was discovered on September 29, 2003 by astronomers from the Lowell Near-Earth-Object Search Observatory (LONEOS) in
Flagstaff, Arizona – A Early Near Object Object (NEO) research project, supported
by NASA that is no longer in operation. Is classified
as a "potentially dangerous asteroid" because of its size and
approaches the Earth's orbit. However, these radar measurements further refine
understanding of the orbit of the 2003 SD220, confirming that
is not a future threat to Earth's impact.
Arecibo, Goldstone and
USRA planetary radar projects are funded through observations of objects near NASA's Earth
Program within the Planetary Defense Coordination
Office(PDCO), which manages the services of the Agency
Planetary Defense Program. The Arecibo Observatory is an installation of the National
Science Foundation operated under cooperative agreement by the University of Central
Florida, Yang Enterprises and Metropolitan University. GBO is an installation of the
National Science Foundation, operated under an Associated Cooperative Agreement
JPL hosts the Near-Earth Center
Object Studies (CNEOS) for NASA's near-Earth observation program.
More information about CNEOS,
asteroids and near Earth objects can be found at:
For more information on
NASA's Office of Planetary Defense Coordination, visit:
More information about the National Science Foundation & # 39; s
The Arecibo Observatory can be found at:
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