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.[ref]
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
Portrait of Geoffrey W. Marcy
. 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. Source.
New to topics? Read the docs here!