Montage of our solar system

Organic compounds known to exist in certain class of meteorites that have fallen to Earth also are found in outer main belt asteroids, recent NASA study showed.

Main belt asteroids orbit the sun between the orbits of Mars and Jupiter.

The study shows that asteroids are possible source of organic matter on Earth and that such matter is widespread in the solar system, said Dr. Robert H. Brown of NASA's Jet Propulsion Laboratory.

Brown and Dr. Dale P. Cruikshank of the Institute for Astronomy in Honolulu, described organic matter found in asteroid 130 Elektra in paper published in Science, the journal of the American Association for the Advancement of Science.

They said their experiments using the cooled- grating array spectrometer at the NASA Infrared Telescope Facility at Mauna Kea, Hawaii, suggested that organic matter- bearing meteorites may have originated in asteroids.

The meteorites are called carbonaceous chondrites and are among the most primitive samples of matter in the solar system.

They determined the existence of hydrocarbons, the basis of organic matter, by observing 3.4 micrometer absorption band of the electromagnetic spectrum in the asteroid.

The band observations made with the infrared telescope matched the same band seen in laboratory sample of known carbonaceous chondrite meteorite. They explained that other asteroids similar to Elektra show bound water in their spectra at 3 micrometers, finding consistent with the bound water in the meteorites.

Brown said that the laboratory meteorite used in the study, known as the Murchison meteorite, contains many complex organic compounds and amino acids, known as the building blocks of life.

He said the study did not identify which, if any of the same specific organic compounds were in the asteroid, but none could be eliminated on the basis of the new data.

The presence of the hydrocarbons on the asteroid does not alone prove that all of the primitive carbonaceous chondrites originated from that source, because comets, including Comet Halley, have the same spectral signature.

But they determined, Brown said, that the occurrence of the organic matter in the asteroids shows that bodies of that type are plausible source for at least one class of carbonaceous chondrites.

It further attests to the widespread distribution of organic matter throughout the solar system and to the fact that complex organic molecules have been transported from remote locations to Earth and other planets.

The NASA research was carried out jointly at JPL, division of the California Institute of Technology, and the Institute for Astronomy at University of Hawaii.

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