Yep, We See It too

Postdoc Butler, SF Stater Marcy Aim Lick Lens, Pick Out Planet

by Robert Sanders

A Berkeley astronomer and a colleague from San Francisco State University have been deluged with inquiries since they confirmed a recent report of a planet orbiting a nearby star--the first time a claimed discovery of a planet around a normal star has withstood scrutiny.

The discovery was reported Oct. 6 at a meeting in Florence, Italy, by Michel Mayor and Didier Queloz of the Geneva Observatory in Switzerland.

The planet confirmation was made by Paul Butler, a postdoctoral researcher at Berkeley; and Geoffrey Marcy, professor of physics and astronomy at San Francisco State University and a visiting scholar to campus.

The two heard about the Florence announcement and used their previously scheduled time at Lick Observatory near San Jose to make independent measurements of the stellar system.

The star, 51 Pegasus, is 40 light years distant and similar in mass to our own Sun. Both the Swiss and California teams calculated the mass of the planet at about half that of Jupiter, though perhaps larger.

Its environment would be a lot different from that of Jupiter, though, because it orbits the star within the star's hot corona. This estimate comes from the measured orbital period of the planet, which is 4.2 days compared to Jupiter's orbital period of 12 years


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