Astronomers find two planetary systems

Planet hunters this week announced they had found two planetary systems, one of which resides only 15 light-years from Earth. Each system features a star roughly similar to the sun and a bizarre entourage that defies ready explanation and may provide fresh insight into planet formation.

Artist’s depiction of the two planets orbiting Gliese 876 (central red dot). Lynette Cook/Science Photo Library, (c) 2001

Among the 50 or so stars where extrasolar planets have been detected, astronomers have reported only one with more than a single planet (SN: 4/17/99, p. 244). The new finds harbor several surprises. One system features an orbiting body so massive it may qualify as a failed star.