[meteorite-list] MRO Images Show Comet Nucleus is Small

[Ron Baalke]

http://www.jpl.nasa.gov/news/news.php?feature=4349

Mars Orbiter Image Shows Comet Nucleus is Small
Jet Propulsion Laboratory
October 20, 2014

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's 
Mars Reconnaissance Orbiter captured views of comet C/2013 A1 Siding 
Spring while that visitor sped past Mars on Sunday (Oct. 19), yielding 
information about its nucleus.

The images are the highest-resolution views ever acquired of a comet coming 
from the Oort Cloud at the fringes of the solar system. Other spacecraft 
have approached and studied comets with shorter orbits. This comet's flyby 
of Mars provided spacecraft at the Red Planet an opportunity to investigate 
from close range.

Images of comet Siding Spring from HiRISE are online at:

http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18618

The highest-resolution of images of the comet's nucleus, taken from a 
distance of about 86,000 miles (138,000 kilometers), have a scale of about 
150 yards (138 meters) per pixel. Telescopic observers had modeled the 
size of the nucleus as about half a mile, or one kilometer wide. However, 
the best HiRISE images show only two to three pixels across the brightest 
feature, probably the nucleus, suggesting a size smaller than half that 
estimate.

For more about HiRISE, visit:

http://hirise.lpl.arizona.edu

For more about Mars Reconnaissance Orbiter, visit:

http://mars.nasa.gov/mro/

For more about comet Siding Spring, including other images of the comet, 
visit:

http://mars.jpl.nasa.gov/comets/sidingspring/

Media Contact

Guy Webster 818-354-6278
Jet Propulsion Laboratory, Pasadena, Calif.
guy.webster at jpl.nasa.gov 

2014-366