Astronomers have for the first time taken infrared pictures of individual
stars in a galaxy called NGC 3379, about 30 million light years from Earth.
The pictures were taken by Michael Gregg of the University of California,
Davis, and the Lawrence Livermore National Laboratory, in collaboration with
colleagues from the Space Telescope Science Institute, the Universidad
Catolica de Chile, and the University of Hertfordshire, England. The
researchers used the Near Infrared Camera and Multiobject Spectrograph
(NICMOS) on the Hubble Space Telescope to take the pictures.
This represents the first time that individual stars have been resolved in
the infrared at this distance, said Gregg.
Infrared images allow astronomers to study what stars are made of. This can
tell astronomers how stars are formed in this galaxy, allowing a comparison
with our own Milky Way and other nearby galaxies.
The high-resolution images also show that NGC 3379 contains variable stars,
which change in brightness over time. Some stars clearly seen on one date
image were no longer visible three months later.
Elliptical galaxies were previously thought to contain few variable stars.
If NGC 3379 is typical, current assumptions about elliptical galaxy
evolution may need to be revised, Gregg said.
NGC 3379, also known as M105, is visible through a small telescope. It appears
as a fuzzy patch in the constellation Leo and is high in the sky just after
dark in June.
The results were presented at the American Astronomical Society meeting in
Pasadena, Calif., earlier this month.
Editors note: Contact Andy Fell for electronic copies of images.
[NOTE: A HST NICMOS image of NGC 3379 is available at
http://www.llnl.gov/urp/IGPP/people/gregg/n3379/n3379.html]
Media contacts:
Michael Gregg, Institute of Geophysical and Planetary Physics
(925) 423-8946, gregg@igpp.ucllnl.org
Andy Fell, News Service
(530) 752-4533, ahfell@ucdavis.edu
