The Lick–Carnegie Exoplanet Survey is a search for exoplanets using the Keck I optical telescope

Optical telescope

An optical telescope is a telescope which is used to gather and focus light mainly from the visible part of the electromagnetic spectrum for directly viewing a magnified image for making a photograph, or collecting data through electronic image sensors....

 of the W. M. Keck Observatory in Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. The survey is sponsored by NASA

NASA

The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 and the National Science Foundation

National Science Foundation

The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...

. The survey comprises a decade of observations. The survey is led by Steven Vogt, professor of astronomy and astrophysics at University of California at Santa Cruz, and R. Paul Butler

R. Paul Butler

R. Paul Butler is an astronomer who searches for extrasolar planets.He received a BA and an MS from San Francisco State University, completing a Master's thesis with Geoffrey Marcy, and then completed his doctoral studies at the University of Maryland, College Park in 1993...

 of the Carnegie Institution.

The search was started as the San Francisco State University Planet Search in 1987 by Geoffrey Marcy

Geoffrey Marcy

Geoffrey W. Marcy is an American astronomer, who is currently Professor of Astronomy at the University of California, Berkeley, famous for discovering more extrasolar planets than anyone else, 70 out of the first 100 to be discovered, along with R...

 and R. Paul Butler

R. Paul Butler

R. Paul Butler is an astronomer who searches for extrasolar planets.He received a BA and an MS from San Francisco State University, completing a Master's thesis with Geoffrey Marcy, and then completed his doctoral studies at the University of Maryland, College Park in 1993...

, using the Lick Observatory

Lick Observatory

The Lick Observatory is an astronomical observatory, owned and operated by the University of California. It is situated on the summit of Mount Hamilton, in the Diablo Range just east of San Jose, California, USA...

. The founding team was the recipient of the 2002 Carl Sagan Memorial Award

Carl Sagan Memorial Award

The Carl Sagan Memorial Award is an award presented jointly by the American Astronautical Society and The Planetary Society to an individual or group "who has demonstrated leadership in research or policies advancing exploration of the Cosmos." The annual award, first presented in 1997, was created...

. It was later renamed the California and Carnegie Planet Search.

The activities of the Lick–Carnegie Extrasolar Planet Search Program include precision Doppler

Doppler spectroscopy

Doppler spectroscopy, also known as radial velocity measurement, is a spectroscopic method for finding extrasolar planets. It involves the observation of Doppler shifts in the spectrum of the star around which the planet orbits....

 based monitoring of over 1330 nearby F, G, K, and M stars for planets using radial velocity

Radial velocity

Radial velocity is the velocity of an object in the direction of the line of sight . In astronomy, radial velocity most commonly refers to the spectroscopic radial velocity...

 measurements at 2–3 m/sec precision. It has contributed over 70% of the presently known exoplanets. These extrasolar planetary systems display a diversity of orbital periods, sizes, and eccentricities, providing new insight into the origins and evolution of planetary systems.

In September 2010, the team announced the discovery of Gliese 581 g

Gliese 581 g

Gliese 581 g , also Gl 581 g or GJ 581 g, is a hypothesized extrasolar planet proven nonexistent by the Geneva Team, orbiting the red dwarf star Gliese 581, 20.5 light-years from Earth in the constellation of Libra. It is the sixth planet discovered in the Gliese 581 planetary system and the fourth...

 in orbit around the red dwarf

Red dwarf

According to the Hertzsprung-Russell diagram, a red dwarf star is a small and relatively cool star, of the main sequence, either late K or M spectral type....

 star

Star

A star is a massive, luminous sphere of plasma held together by gravity. At the end of its lifetime, a star can also contain a proportion of degenerate matter. The nearest star to Earth is the Sun, which is the source of most of the energy on Earth...

 Gliese 581

Gliese 581

Gliese 581 is a red dwarf star with spectral type M3V, located 20.3 light years away from Earth in the constellation Libra. Its estimated mass is about a third of that of the Sun, and it is the 89th closest known star system to the Sun. Observations suggest that the star has at least six planets:...

. The observations place the planet in an area where liquid water could exist on the planet's surface, i.e. a habitable zone

Habitable zone

In astronomy and astrobiology, a habitable zone is an umbrella term for regions that are considered favourable to life. The concept is inferred from the empirical study of conditions favourable for Life on Earth...

. If confirmed, this would be the first strong case for a potentially habitable Earth-like exoplanet yet discovered.