Geoffrey W. Marcy
= Geoffrey W. Marcy
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{wiki=Geoffrey_Marcy}
<Geoffrey W. Marcy> worked on the <radial velocity> method for finding <exoplanets>, including precision <iodine-cell Doppler calibration>. His paper with <R. Paul Butler> combined a wide recorded stellar <radiation spectrum> with reference absorption lines introduced directly into the stellar beam.
Measuring a small <Doppler shift> requires distinguishing real stellar <motion> from instrumental changes. The superimposed reference constrains the <spectrograph>'s <wavelength> scale and <point spread function> during the exposure, allowing the stellar shift to be fitted with those effects included. The paper reported year-long tests of the technique on three solar-type <stars>.<Precision Radial Velocities with an Iodine Absorption Cell by Geoffrey W. Marcy and R. Paul Butler>[p. 270, abstract and introduction: iodine reference, spectrograph response and three-star tests]{ref}
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{title=Portrait of <Geoffrey W. Marcy>}
{description=Laurie Hatch (embedded EXIF author); Commons summary credits NASA / Media Telecon. Via Wikimedia Commons; credits and usage information are on the linked source file page.}
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