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Probing the disk of Beta Pictoris.

Located some 53 light-years from Earth, Beta Pictoris is the best-known example of a star surrounded by a disk of gas and dust -- a possible solar system in the making. Researchers believe that such a disk once encircled our sun, giving rise to the planets and their moons some 4.6 billion years ago.

This visible-light photo is the sharpest image ever taken of Beta Pictoris' dusty disk. David A. Golimowski of Johns Hopkins University in Baltimore and his collegues took the image last December using a 2.5-meter telescope at Las Campanas Observatory in La Serena, Chile.

A coronagraph blocked out the bright light emitted by the star so that researchers could not record its faint disk. This novel coronagraph contains a mirror that flexes as needed to compensate for image distortion caused by Earth's turbulent atmosphere, enabling astronomers to resolve features as small as 1 billion kilometers across. Viewed edge-on, with the blocked-out star in the center, the disk's highest-intensity regions appear brightest in this false-color portrait. Bright spots at the top and bottom of the darkened star are artifacts.

Another team of researchers reports that the inner regions of the disk contain the same type of dust as comets and Earth rocks. Sergio B. Fajardo-Acosta of the State University of New York at Stony Brook and his colleagues analyzed the infrared spectra of light from the disk at NASA's Infrared Telescope Facility in Hawaii. Some of the light emissions, they find, stem from particles of crystalline silicate -- the same mineral spewed out by Comet Halley in 1986 as it encountered the intense heat of the sun.

Fajardo-Acosta and his co-workers say this suggests that the inner part of the Beta Pictoris disk contains many cometary bodies too distant for a telescope to image; these bodies would shed silicate dust when they pass near their parent star.

Other astronomers have now produced the first infrared image of the Beta Pictoris disk (see photo), using the 1.5-meter telescope at the Cerro Tololo Inter-American Observatory in La Serena, Chile. The colors and reflectivity of the light from the outer part of the disk indicate its composition may be similar to that of the icy moons of Jupiter, Saturn and Uranus, report Melissa L. Nischan of Franklin and Marshall College in Lancaster, Pa., and two colleagues. Thus, the outer part of the disk may contain material left over from the creation of bodies similar to those in the outer solar system.
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Title Annotation:solar system research
Author:Cowen, Ron
Publication:Science News
Article Type:Brief Article
Date:Jun 20, 1992
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