January 8, 1999
Karen Thomas, Media Relations Coordinator, (403) 220-5727

U of C Astronomers Open New Window Into The Lives of Stars

Steven Gibson and Russ Taylor, astronomers in the University of Calgary's
Department of Physics and Astronomy, have used radio telescopes to gain a whole
new vantage point in observing the first step in the formation of new stars.

``I am excited to report that we may finally have the first detailed view of
the evolution of hydrogen clouds from atoms to molecules -- the initial step in
the formation of new stars,'' says Gibson.

Gibson and Taylor present their findings today at an international conference
of the American Astronomical Society involving some 2,000 astronomers in
Austin, Texas.

The U of C researchers have discovered a large collection of interstellar
clouds of cold hydrogen atoms. These clouds have been revealed in detail for
the first time by the Canadian Galactic Plane Survey, an international
collaboration to map a large section of our home galaxy, the Milky Way, with
radio telescopes. The gas in many of these clouds appears to be condensing from
free atoms into molecules, making the clouds more cold, dense, and dark.

Gibson and Taylor believe they may have captured clouds evolving from the
atomic phase to the molecular phase, in a region of our galaxy where such
transitions are predicted to occur, but have not been observed before now.

The gaseous clouds are located in the next spiral arm outside of our own, known
as the Perseus Arm, about 7,000 light years from the Earth.  The Milky Way
Galaxy is a disk of stars measuring about 100,000 light years across, with a
central concentration of matter from which several spiral arms sweep outwards
in a whirlpool pattern. The Sun is in one of these arms, and the hydrogen
clouds that the U of C researchers have found are in the next arm out.

The radio waves, detected by telescopes at the Dominion Radio Astrophysical
Observatory near Penticton, British Columbia, left the hydrogen clouds some
7,000 years ago. However, the lifetimes of such clouds are thought to be
millions of years -- so they are still there now, though they may have changed
in appearance.  These observations represent a real test of the spiral arm
theory of star formation, which predicts the transformation of material, first
from atomic to molecular gas, and then into stars, as it enters spiral arms on
its journey around the galaxy. Until now, no one has been able to study that
first transition in this sort of detail.

The ongoing research of Gibson and Taylor is supported by a grant from the
Natural Sciences and Engineering Research Council of Canada.

For more information contact Steven Gibson at (512) 404-4650/4651/4652. Email
him at gibson@ras.ucalgary.ca. To see photos, visit the web
www.ras.ucalgary.ca/~gibson/hisa/.