Spectroscopic Planetary Detection

The goal of this investigation is to determine the extent to which planetary companions to solar-type stars can be detected by measuring the small Doppler reflex which their orbital motion induces in the spectrum of their parent star. Several research groups are actively engaged in making such measurements. A possible problem with such a method is that changes in stellar surface convection may produce spurious changes in stellar spectra, which mimic the effect of planetary companions. The report of the most recent NASA Planetary Detection Workshop called for an investigation of the Sun's integrated radial velocity behavior over the long term, so that solar-cycle effects can be identified and their impact on planetary detection efforts can be evaluated. Accordingly, we are measuring the spectrum of the Sun-as-a-star using Fourier transform and laser heterodyne spectroscopy to search for small Doppler shifts related to the solar cycle.