Planetary systems

The past decade brought direct evidence of the previously surmised exoplane tary systems. A variety of planetary system types exist: those around pulsa rs, around both young and old main-sequence stars (as evidenced by planetes imal disks of the Beta Pictoris-type), and the mature giant exoplanets foun d in radial velocity surveys. The surprising diversity of the exoplanetary systems is addressed by several theories of their origin.