The international Anglo-Australian Planet Search Team, in part sponsored by
the National Science Foundation (NSF), has now found more extrasolar
planets in the Southern Hemisphere than any other group. The team’s latest
find brings the number of extrasolar planets to 100.

And with this total,
astronomers are beginning to see patterns in planet characteristics. “When
we first started out, we found planets close in to their parent stars,”
says team member Chris McCarthy of the Carnegie Institution of Washington.
“But as the planet search program has matured, we’re finding more planets
farther out and in nearly circular orbits. This means that we are getting
closer to detecting more systems that are similar to our own solar system.”

Dr. Hugh Jones, of Liverpool John Moores University in the UK, was the lead
astronomer for this latest project, which was supported by three
governments. The new planet weighs in at about 1.2 Jupiters. It orbits star
Tau 1 Gruis, found in the southern constellation Grus (the crane), 100
light-years from Earth. It is located about the same distance from its star
as our asteroid belt is from our Sun (2.5 astronomical units with 1 AU
being the Earth-Sun distance). And its orbit is roughly circular.

Based on
the 15-year survey, which Paul Butler of Carnegie and Geoff Marcy of U.C.
Berkeley have headed at the Lick Observatory, about 12% of the Sun-like
stars in our galaxy have planets that can be detected orbiting their stars
within about 5 AU. As the body of extrasolar planets grows, more planets
are being found farther out. This finding supports the idea that giant
planets in solar systems may form at great distances from their stars and
later move inward.

The Anglo-Australian Planet Search team includes astronomers from the UK,
Australia, and the United States. From the UK: Dr. Hugh R. A. Jones,
Liverpool John Moores University, and Dr. Alan J. Penny, Rutherford
Appleton Laboratory. From Australia: Dr. Chris G. Tinney, Anglo-Australian
Observatory, and Dr. Brad Carter, University of Southern Queensland. From
the US: Dr. R. Paul Butler and Dr. Chris McCarthy, Carnegie Institution of
Washington, and Dr. Geoffrey W. Marcy, University of California Berkeley
and San Francisco State University.

In addition to the NSF, support for
this work comes from Anglo-Australian Observatory, which operates and
maintains the 3.9-m Anglo-Australian Telescope, (http://www.aao.gov.au);
The Particle Physics and Astronomy Research Council, which funds UK
astronomy research, ( http://www.pparc.ac.uk/home.asp); and the Australian
Telescope Allocation Committee. Also see www.exoplanets.org

The Carnegie Institution of Washington (www.CarnegieInstitution.org) has
been a pioneering force in basic scientific research since 1902. It is a
private, nonprofit organization with six research departments in the U.S.:
Plant Biology, Global Ecology, Observatories, Embryology, the Geophysical
Laboratory, and the Department of Terrestrial Magnetism.

Contact at Carnegie: Chris McCarthy at 202- 478-8862, e-mail
chris@dtm.ciw.edu.; Paul Butler at paul@dtm.ciw.edu; Contact at U.C.
Berkeley: Geoffrey W. Marcy at gmarcy@astron.berkeley.edu