[meteorite-list] Radar Images Provide New Details on Halloween Asteroid (2015 TB145)

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4763

Radar Images Provide New Details on Halloween Asteroid
Jet Propulsion Laboratory
November 3, 2015

[Images]
Asteroid 2015 TB145 is depicted in eight individual radar images collected 
on Oct. 31, 2015 between 5:55 a.m. PDT (8:55 a.m. EDT) and 6:08 a.m. PDT 
(9:08 a.m. EDT). 
Image Credit: NASA/JPL-Caltech/GSSR/NRAO/AUI/NSF

The highest-resolution radar images of asteroid 2015 TB145's safe flyby 
of Earth have been processed. NASA scientists used giant, Earth-based 
radio telescopes to bounce radar signals off the asteroid as it flew past 
Earth on Oct. 31 at 10 a.m. PDT (1 p.m. EDT) at about 1.3 lunar distances 
(300,000 miles, or 480,000 kilometers) from Earth. Asteroid 2015 TB145 
is spherical in shape and approximately 2,000 feet (600 meters) in diameter.

"The radar images of asteroid 2015 TB145 show portions of the surface 
not seen previously and reveal pronounced concavities, bright spots that 
might be boulders, and other complex features that could be ridges," said 
Lance Benner of NASA's Jet Propulsion Laboratory in Pasadena, California, 
who leads NASA's asteroid radar research program. "The images look distinctly 
different from the Arecibo radar images obtained on Oct. 30 and are probably 
the result of seeing the asteroid from a different perspective in its 
three-hour rotation period."

Radar images of asteroid 2015 TB145 acquired by Arecibo Observatory are 
available at these sites:

http://on.fb.me/1MahsY8

https://twitter.com/AreciboRadar/status/661293813713928192

To obtain these highest-resolution radar images of the asteroid, scientists 
used the 230-foot (70-meter) DSS-14 antenna at Goldstone, California, 
to transmit high-power microwaves toward the asteroid. The signal bounced 
off the asteroid, and its radar echoes were received by the National Radio 
Astronomy Observatory's 100-meter (330-foot) Green Bank Telescope in West 
Virginia. The radar images achieve a spatial resolution as fine as 13 
feet (4 meters) per pixel.

The next time that asteroid 2015 TB145 will be in Earth's neighborhood 
will be in September 2018, when it will make a distant pass at about 24 
million miles (38 million kilometers), or about a quarter the distance 
between Earth and the sun.

Radar is a powerful technique for studying an asteroid's size, shape, 
rotation, surface features and surface roughness, and for improving the 
calculation of asteroid orbits. Radar measurements of asteroid distances 
and velocities often enable computation of asteroid orbits much further 
into the future than would be possible otherwise.

NASA places a high priority on tracking asteroids and protecting our home 
planet from them. In fact, the U.S. has the most robust and productive 
survey and detection program for discovering near-Earth objects (NEOs). 
To date, U.S. assets have discovered about 98 percent of known NEOs.

In addition to the resources NASA puts into understanding asteroids, it 
also partners with other U.S. government agencies, university-based astronomers, 
and space science institutes across the country, often with grants, interagency 
transfers and other contracts from NASA, and also with international space 
agencies and institutions that are working to track and better understand 
these objects. In addition, NASA values the work of numerous highly skilled 
amateur astronomers, whose accurate observational data helps improve asteroid 
orbits after they are found.

JPL hosts the Center for Near-Earth Object Studies for NASA's Near-Earth 
Object Observations Program within the agency's Science Mission Directorate.

More information about asteroids and near-Earth objects is at these sites:

http://neo.jpl.nasa.gov

http://www.jpl.nasa.gov/asteroidwatch


Media Contact

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

Charles Blue
National Radio Astronomy Observatory
434.296.0314
cblue at nrao.edu 

2015-341