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NSF PR 99-24 - April 15, 1999
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Astronomy Teams Find First Multi-Planet System, Other
Than Our Own, Orbiting Star
The first believed multiple planet system orbiting
around a sun-like star has been found by independent
teams of astronomers, including National Science Foundation
(NSF)-supported researchers from San Francisco State
University and from the Anglo-Australian Observatory.
In 1996 San Francisco State's Geoffrey Marcy and R.
Paul Butler of the Anglo-Australian Observatory detected
a near Jupiter-sized planet orbiting the star Upsilon
Andromedae.
Recently, the scientists, after analyzing 11 years
of telescopic observations at Lick Observatory near
San Jose, Calif., picked up signals of what appears
to be two additional planets within the same system
based on newly gathered data. The new data indicates
there are at least a trio of planets orbiting this
star, making the Upsilon Andromedae grouping the first
solar system ever found that mimics our own.
These newly discovered planets are more distant from
its star than the one discovered three years earlier.
The middle planet is estimated at twice the size of
Jupiter, and the outermost planet, four times Jupiter's
mass. Both orbit its star in elliptical patterns,
as in previously known discoveries of extrasolar planets.
Meanwhile, a second team of astronomers from the Harvard
Smithsonian Center for Astrophysics (CfA) in Cambridge,
Mass., and from the NSF-supported High Altitude Observatory
(HAO) in Boulder, Colo. found independent evidence
of the two new planets using the Smithsonian's Whipple
Observatory near Tuscon, Ariz.
Butler is the lead author of a paper that describes
the trio of planets for the Astrophysical Journal.
Contributing colleagues include Marcy, Debra Fischer
of San Francisco State, Robert Noyes, Sylvain Korzennik,
Peter Nisenson and Adam Contos, all of the CfA, and
Timothy Brown of HAO.
"These planets are giants," James P. Wright, who heads
special programs in astronomy for NSF's Division of
Astronomical Sciences, said. "It's impressive that
these results have been independently corroborated
by these teams."
Editors: At San Francisco State University,
media contact is: Blake Edgar, 415-338-6747, bedgar@sfsu.edu
At CfA, Harvard, media contact is: Megan Watzke, 617-495-7463,
mwatzle@cfa.harvard.edu
At UCAR, media contact is: Anatta, 303-497-8604, anatta@ucar.edu
For images, see: http://www.physics.sfsu.edu/~gmarcy/planetsearch/upsand.html
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