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First measurement of the age of cometary material

Date:
February 26, 2010
Source:
DOE/Lawrence Livermore National Laboratory
Summary:
Though comets are thought to be some of the oldest, most primitive bodies in the solar system, new research on comet Wild 2 indicates that inner solar system material was transported to the comet-forming region at least 1.7 million years after the formation of the oldest solar system solids.
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Secondary electron image of the Coki section analyzed in this study showing mineral shards surrounded by compressed aerogel.
Credit: Image courtesy of DOE/Lawrence Livermore National Laboratory

Though comets are thought to be some of the oldest, most primitive bodies in the solar system, new research on comet Wild 2 indicates that inner solar system material was transported to the comet-forming region at least 1.7 million years after the formation of the oldest solar system solids.

The research by Lawrence Livermore National Laboratory scientists and colleagues provides the first constraint on the age of cometary material from a known comet.

The findings are published in the Feb. 25 edition of Science Express.

The NASA Stardust mission to comet Wild 2, which launched in 1999, was designed around the premise that comets preserve pristine remnants of materials that helped form the solar system. In 2006, Stardust returned with the first samples from a comet.

Though the mission was expected to provide a unique glimpse into the early solar system by returning a mix of solar system condensates, amorphous grains from the interstellar medium and true stardust (crystalline grains originating in distant stars), the initial results painted a different picture. Instead, the comet materials consisted of high-temperature materials including calcium-aluminum rich inclusions (CAIs), the oldest objects formed in the solar nebula. These objects form in the inner regions of the solar nebula and are common in meteorites.

The presence of CAIs in comet Wild 2 indicates that the formation of the solar system included mixing over radial distances much greater than has been recognized by scientists in the past.

"The inner solar system material in Wild 2 underscores the importance of radial transport of material over large distances in the early solar nebula," said lead author Jennifer Matzel of the Laboratory's Institute of Geophysics and Planetary Science and the Glenn T. Seaborg Institute. "These findings also raise key questions regarding the timescale of the formation of comets and the relationship between Wild 2 and other primitive solar nebula objects." Analysis showed that the inner solar system materials formed 1.7 million years after the onset of CAI formation.

Other LLNL team members include Hope Ishii, Ian Hutcheon, John Bradley, Peter Weber and Nick Teslich. Colleagues include scientists from the University of Washington, University of California, Los Angeles and the Smithsonian Institution.

Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory that develops science and engineering technology and provides innovative solutions to our nation's most important challenges. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.


Story Source:

The above post is reprinted from materials provided by DOE/Lawrence Livermore National Laboratory. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. E. P. Matzel, H. A. Ishii, D. Joswiak, I. D. Hutcheon, J. P. Bradley, D. Brownlee, P. K. Weber, N. Teslich, G. Matrajt, K. D. Mckeegan, G. J. Macpherson. Constraints on the Formation Age of Cometary Material from the NASA Stardust Mission. Science, Published Online February 25, 2010 DOI: 10.1126/science.1184741

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DOE/Lawrence Livermore National Laboratory. "First measurement of the age of cometary material." ScienceDaily. ScienceDaily, 26 February 2010. <www.sciencedaily.com/releases/2010/02/100225164851.htm>.
DOE/Lawrence Livermore National Laboratory. (2010, February 26). First measurement of the age of cometary material. ScienceDaily. Retrieved July 30, 2015 from www.sciencedaily.com/releases/2010/02/100225164851.htm
DOE/Lawrence Livermore National Laboratory. "First measurement of the age of cometary material." ScienceDaily. www.sciencedaily.com/releases/2010/02/100225164851.htm (accessed July 30, 2015).

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