World-wide Doppler monitoring of 300 FGK main sequence stars has revealed eight stars that exhibit Keplerian velocity variations indicative of planetary companions. Ongoing Doppler planet searches of 500 stars will improve the statistics of their occurrence and orbital characteristics.
Selection effects favor the detection of companions with small orbital semimajor axes.
Nonetheless, these jupiters within 2 AU imply that they formed either in situ or beyond several AU but suffered inward orbital migration. Indeed, inward migration looms as an inexorable aspect of planet formation, either by tidal coupling to the T Tauri disk or by the viscous drainage of material inward in the accretion disk. The migration time for giant planets at 5 AU appears to be less than a million years, both theoretically and observationally. Thus, jupiters may commonly migrate inward during the T Tauri phase, while other giant planets continue to form farther out. This link was provided by the author.