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Colorful mix of asteroids discovered, may aid future space travel

Date:
September 7, 2010
Source:
Northern Arizona University
Summary:
New research from NASA's Spitzer Space Telescope reveals that asteroids somewhat near Earth, termed near-Earth objects, are a mixed bunch, with a surprisingly wide array of compositions.
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This image, taken by NASA's Near Earth Asteroid Rendezvous mission in 2000, shows a close-up view of Eros, an asteroid with an orbit that takes it somewhat close to Earth. NASA's Spitzer Space Telescope observed Eros and dozens of other near-Earth asteroids as part of an ongoing survey to study their sizes and compositions using infrared light.
Credit: NASA/JHUAPL

New research from NASA's Spitzer Space Telescope reveals that asteroids somewhat near Earth, termed near-Earth objects, are a mixed bunch, with a surprisingly wide array of compositions.

Like the chocolates and fruity candies inside a piñata, these asteroids come in assorted colors and compositions. Some are dark and dull; others are shiny and bright. The Spitzer observations of 100 known near-Earth asteroids demonstrate that their diversity is greater than previously thought.

The findings are helping astronomers better understand near-Earth objects as a whole -- a population whose physical properties are not well known.

"These rocks are teaching us about the places they come from," said David Trilling, assistant professor of physics and astronomy at Northern Arizona University, and lead author of a new paper on the research appearing in the September issue of Astronomical Journal. "It's like studying pebbles in a streambed to learn about the mountains they tumbled down."

One of the mission's programs is to survey about 700 near-Earth objects, cataloguing their individual traits. By observing in infrared, Spitzer is helping to gather more accurate estimates of asteroids' compositions and sizes than what is possible with visible-light alone.

Trilling and his team have analyzed preliminary data on 100 near-Earth asteroids so far. They plan to observe 600 more over the next year. There are roughly 7,000 known near-Earth objects out of a population expected to number in the tens to hundreds of thousands.

"Very little is known about the physical characteristics of the near-Earth population," Trilling said. "Our data will tell us more about the population, and how it changes from one object to the next. This information could be used to help plan possible future space missions to study a near-Earth object."

The data show that some of the smaller objects have surprisingly high albedos (a measurement of how much sunlight an object reflects). Since asteroid surfaces become darker with time due to exposure to solar radiation, the presence of lighter, shinier surfaces for some asteroids may indicate that they are relatively young. This is evidence for the continuing evolution of the near-Earth object population.

In addition, the asteroids observed so far have a greater degree of diversity than expected, indicating that they might have different origins. Some might come from the main belt between Mars and Jupiter, and others could come from farther out in the solar system. This diversity also suggests that the materials that went into creating the asteroids -- the same materials that make up our planets -- were probably mixed together like a big solar-system soup very early on in its history.

The research complements that of NASA's Wide-field Infrared Survey Explorer, or WISE, an all-sky infrared survey mission up in space now. WISE has already observed more than 430 near-Earth objects. Of these, more than 110 are newly discovered.

In the future, both Spitzer and WISE will reveal even more about the "flavors" of near-Earth objects. This could reveal new clues about how the cosmic objects might have dotted our young planet with water and organics -- ingredients needed to jump-start life.

Other authors include Cristina Thomas, a post-doctoral scholar of physics and astronomy at NAU, and researchers from around the world.


Story Source:

The above post is reprinted from materials provided by Northern Arizona University. Note: Materials may be edited for content and length.


Journal Reference:

  1. D. E. Trilling, M. Mueller, J. L. Hora, A. W. Harris, B. Bhattacharya, W. F. Bottke, S. Chesley, M. Delbo, J. P. Emery, G. Fazio, A. Mainzer, B. Penprase, H. A. Smith, T. B. Spahr, J. A. Stansberry, C. A. Thomas. Exploreneos. I. Description and First Results from the Warmspitzernear-Earth Object Survey. The Astronomical Journal, 2010; 140 (3): 770 DOI: 10.1088/0004-6256/140/3/770

Cite This Page:

Northern Arizona University. "Colorful mix of asteroids discovered, may aid future space travel." ScienceDaily. ScienceDaily, 7 September 2010. <www.sciencedaily.com/releases/2010/09/100906142753.htm>.
Northern Arizona University. (2010, September 7). Colorful mix of asteroids discovered, may aid future space travel. ScienceDaily. Retrieved July 4, 2015 from www.sciencedaily.com/releases/2010/09/100906142753.htm
Northern Arizona University. "Colorful mix of asteroids discovered, may aid future space travel." ScienceDaily. www.sciencedaily.com/releases/2010/09/100906142753.htm (accessed July 4, 2015).

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