METH%USC-ISI@sri-unix.UUCP (11/09/83)
NASA News Release 83-172
IRAS DISCOVERS GIANT DUST SHELLS AROUND THE STAR BETELGEUSE
Astronomers studying data from the Infrared Astronomical Satellite at
the University of Groningen, the Netherlands, have discovered three giant dust
shells that are asymmetrically placed around the star Betelgeuse.
IRAS, which was launched Jan. 25, 1983, is a joint project of the
United States, the Netherlands and the United Kingdom.
It was already known that Betelgeuse, a red supergiant star, loses
material. The IRAS data show evidence for the presence of dust shells which
extend more than four light years from the star. At this distance, the
material must have left the star 100,000 years ago. IRAS observations thus
allow astronomers to study the earliest stages in the episode of mass loss.
A surprising result is the strong asymmetry in the distribution of dust
around Betelgeuse. While it is thought that the process of mass loss is more
or less symmetrical around the star, all material observed there by IRAS is
seen north of the star. A possible reason for this asymmetry is a strong
deformation of the symmetrically ejected material by the ambient interstellar
gas through Betelgeuse moves.
Betelgeuse is one of the brightest stars in the constellation Orion.
It is conspicuously red and belongs to the class of red supergiants. It is one
thousand times larger than the Sun; if placed in our solar system, it would
extend to the planet Jupiter.
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At a news coference today at NASA HQ in Washington, other interesting IRAS
discoveries were announced. Of interest is the discovery of three bright bands
surrounding the sun between Mars and Jupiter, one along the ecliptic, the other
two about 9 degrees above and below the ecliptic. One explanation for the
bands is debris from asteroidal collisions all movin in orbits inclined 9
degrees from the ecliptic. The result of such orbits would appear to be three
bright bands in the orientation observed by IRAS.
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