San Francisco State University

Dr. Geoff Marcy and Dr. Paul Butler

Graphic by Leigh Anne McConnaughey

Since 1987 Geoff Marcy and Paul Butler have been searching for extrasolar planets here at San Francisco State University. Using a high precision velocity measurement technique, over 100 stars have been monitored for more than eight years in an attempt to indirectly detect planetary companions. Late in 1995 the first such companion was found by two Swiss astronomers, Michel Mayor and Didier Queloz, around the star 51 Pegasi. Our project was able to make a confirmation of the Swiss discovery making this the first verified planet ever found orbiting a solar type star. In early 1996 we announced the discovery of two more planets outside of our solar system, one each orbiting the stars 47 Ursae Majoris and 70 Virginis.

June 1996, a planetary companion to HR5185 has been detected! Check out the radial velocity curve. The minimum mass of this companion is 3.87 Jupiter masses.

We are just about finished analyzing our current data on all 120 stars in our project!

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We do our observing at Lick Observatory.

Check in here to learn about the physics involved and how our technique works.

By popular demand, here is the current list of stars we are observing.

Planets that we have discovered or confirmed:

70 Virginis b (discovered)

47 Ursae Majoris b (discovered)

HR3522 (discovered)

HD114762 (possible re-classification)

HR5185

Stay tuned for more!

Here is a histogram that still needs more data to really understand, but provides a little "food for thought" regarding the mass distribution of detected sub-stellar companions. Is there a "Brown Dwarf desert" out past ~20 M jup? Please see the discussion in our paper on 70 Virginis b.

Graphic by Leigh Anne McConnaughey

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Links to other astronomical sites.

Discovery Channel Online article about the planetsearch.

SERENDIP - listening for alien radio!

Exploration of Neighboring Planetary Systems - NASA's roadmap for finding extrasolar planets

Pulsar planet page - check out the strange and unexpected with the pulsar planets.

Darwin - an interferometer in space proposal for finding Earth-like planets.

The Extrasolar Planets Encylopedia - a site in France with more on planets

American Astronomical Society - check out the online Letters publication

SETI - once you find planets you also want to know if anyone is home.

Women in Astronomy - great link to give credit where credit is due!

The Astronomical Society of the Pacific magazine Mercury

Sky and Telescope online!

Astronomy magazine is here too!

Hope you find this site useful and informative. I hope to be able to improve it in time and of course add more planets as we discover them! Please email me with comments, suggestions, or questions regarding our project.