THE FOLLOWING RELEASE WAS RECEIVED FROM THE UNIVERSITY OF WYOMING, IN
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THE END.  Steve Maran, American Astronomical Society


UW SCIENTIST FINDS NEW TYPE OF STAR
	Nov. 7, 1997 -- A new type of star has been discovered by an
international team of astronomers, led by Dr. Steve Howell of the University
of Wyoming.
	Howell, an assistant professor in UW's Department of Physics and
Astronomy, has been working in collaboration with Saul Rappaport of the
Massachusetts Institute of Technology, Mike Politano of Arizona State
University, Peter Hauschildt of the University of Georgia, and Vik
Dhillon of the Royal Greenwich Observatory to understand the life cycles
of the two stars contained within very old binary systems.
	Many stars form originally as binary systems, where two stars
orbit around each other for an eternity held together 
by their mutual gravitational
attraction. Some binary stars are so close together that their orbit could
fit within the size of our sun. This nearness also affects each star's
life cycle.
	Howell and his collaborators used observations from some of the
world's largest telescopes, including the William Herschel Telescope
located in the Canary Islands, 
and theoretical models run on supercomputers to
develop new theories about the evolution of these old binaries. They now
believe that a new type of star exists within some of these binary systems.
	"The discovery of a new type of star is not something that happens
everyday," Howell says. "Early this century, astronomers used both
theory and observation to discover white dwarfs, neutron stars, and
black holes. Until now, no other stellar types were found."
	Stars shine due to energy production in their cores, mainly by
conversion of hydrogen to helium via nuclear reactions. When the
hydrogen supply is used up, a star must re-adjust its overall structure
to ward off collapse due to the ever present force of gravity. After a
relatively brief period of million of years, stars generally end their
lives as
one of three types of stellar end-products: white dwarfs, neutron stars,
or black holes -- the latter being the end state of the most massive stars.
	"In many binary systems, the initially more massive star ends its
life and becomes a white dwarf, while the initially less massive star
tries to evolve normally, but all the while loses mass to the white
dwarf," Howell says. "Eventually, all that remains of the less massive
star is an exposed stellar core with a size near that of the planet
Jupiter and a mass of only 5/100th or so of its original value. Having
used up or lost essentially all its hydrogen, this very small star has
no remaining energy generation. It cannot ever become one of the usual
stellar end-products. Therefore, it has a structure unlike any other
kind of known star."
	Howell says that while the work that led to the 
discovery of this new type
of star is over, further observational and theoretical work will
continue to understand its stellar state.
	"It is pleasing to know that the universe still holds mysteries and
with diligence and patience, we get to peek inside and discover some
small new part for ourselves," he says.
	For more information, call Howell at (307) 766-5402.
                                 -PCD-

Patrick Davarn, senior editor
UW News Service
davarn@uwyo.edu
(307) 766-5456
http://www.uwyo.edu