Heat-Sensitive Infrared Sheds New Light on Asteroids

 
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An artist's conception of two possible views of asteroid 2011 MD. (Image courtesy of NASA Jet Propulsion Laboratory)

Astronomers using NASA's Spitzer Space Telescope have measured the size of an asteroid candidate for NASA's Asteroid Redirect Mission (ARM). ARM is a proposed spacecraft concept to capture either a small asteroid or a boulder from an asteroid. The near-Earth asteroid, called 2011 MD, was found to be roughly 20 feet (6 meters) in size, and its structure appears to contain a lot of empty space, perhaps resembling a pile of rubble. Spitzer's infrared vision was key to sizing up the asteroid.

"From its perch up in space, Spitzer can use its heat-sensitive infrared vision to spy asteroids and get better estimates of their sizes," said Michael Mommert, NAU postdoctoral researcher and lead author of a new study. The study ("Physical Properties of Near-Earth Asteroid 2011 MD") appeared in the June 20 edition of the Astrophysical Journal Letters. David Trilling, NAU Associate Professor of Astronomy, leads the team of astronomers.

The Spitzer results confirm that asteroid 2011 MD has characteristics suitable for the ARM proposal, elevating it to the "valid candidate" level. Valid candidates are those asteroids with the right size, mass, and rotation rate to be feasibly captured by the robotic spacecraft. Two other valid candidates have been identified so far. (The proposal to capture a boulder from an asteroid involves a different set of criteria.) NASA continues to search for and find new potential candidates using its ground-based asteroid survey programs.

To read the rest of the article, visit http://www.jpl.nasa.gov/asteroidwatch/newsfeatures.cfm?release=2014-193&rn=asteroid.xml&rst=2014-193.  

What seemed to be rock-solid assumptions about the nature of small asteroids may end in collections of rubble or even a cloud of dust. To learn more, visit http://news.nau.edu/nasa-nau-researchers-welcome-unexpected-asteroid-findings/#.U7HL_UD9XwM