Geoffrey W. Marcy

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An extremely low mass companion to the solar-type star 70 Virginis is inferred from the observed periodic Doppler reflex motion of the primary during 8 yr. The minimummass (M2 sin i) of 70 Vir “B” is 6.6 Jovian masses (MJ), which falls in the mass range associated with “extrasolar giant planets” (0.3–15 MJ ). An orbital fit to the velocities yields a period(More)
Doppler measurements from Keck exhibit a sinusoidal periodicity in the velocities of the G0 dwarf HD 209458, having a semiamplitude of 81 m s and a period of 3.5239 days, which is indicative of a “51 Peg–like” planet with a minimum mass ( ) of 0.62 MJup and a semimajor axis of 0.046 AU. Follow-up photometry reveals M sin i a drop of 0.017 mag at the(More)
Determining whether Earth-like planets are common or rare looms as a touchstone in the question of life in the universe. We searched for Earth-size planets that cross in front of their host stars by examining the brightness measurements of 42,000 stars from National Aeronautics and Space Administration's Kepler mission. We found 603 planets, including 10(More)
Ten days of photometric data were obtained during the commissioning phase of the Kepler mission, including data for the previously known giant transiting exoplanet HAT-P-7b. The data for HAT-P-7b show a smooth rise and fall of light from the planet as it orbits its star, punctuated by a drop of 130 +/- 11 parts per million in flux when the planet passes(More)
On 2011 February 1 the Kepler mission released data for 156,453 stars observed from the beginning of the science observations on 2009 May 2 through September 16. There are 1235 planetary candidates with transit-like signatures detected in this period. These are associated with 997 host stars. Distributions of the characteristics of the planetary candidates(More)
The questions of how planets form and how common Earth-like planets are can be addressed by measuring the distribution of exoplanet masses and orbital periods. We report the occurrence rate of close-in planets (with orbital periods less than 50 days), based on precise Doppler measurements of 166 Sun-like stars. We measured increasing planet occurrence with(More)
1Astronomy Department, University of California, Berkeley, CA 94720, USA 2Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Rd NW, Washington DC 20015-1305, USA 3Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132, USA 4UCO/Lick Observatory, University of California at Santa(More)
We report Doppler measurements for six nearby Gand K-type main-sequence stars that showmultiple low-mass companions, at least one of which has planetary mass. One system has three planets, the fourth triple-planet system known around a normal star, and another has an extremely low minimum mass of 18 M . HD 128311 (K0 V) has two planets (one previously(More)
Doppler measurements from the Keck/HIRES spectrometer of the G3 V star HD 187123 reveal Keplerian variations with a period of 3.097 days and a semiamplitude of 72 m s. An orbital fit yields a companion mass of , a semimajor axis of AU, and an eccentricity of M 5 0.52 M / sin i a 5 0.042 e 5 0.03 JUP (consistent with zero). HD 187123 appears similar to the(More)