The collection of odd planets discovered in distant solar systems has gotten stranger,
even frightening. Thats the assessment of planet hunter Geoffrey Marcy of the University
of California, Berkeley, after finding a gargantuan planet 17 times as massive as Jupiter.
The whopper planet, orbiting a sun-like star in the constellation Serpens, is twice as
massive as any other planet ever found. It has confounded theorists who did not think planets
could form on such a scale.
The whopper might be a brown dwarf star, insufficiently hot for fusion to have ignited it,
says R. Paul Butler of the Carnegie Institution of Washington, D.C. Yet it orbits close enough
to the central starat a distance about three times the distance from Earth to the sunin an
area where planets normally form. Gravitational disturbances would make it difficult for a
brown dwarf star to form that close to another star.
The giant could be a new class of object entirely, Butler says. I cant wait until the theorists
explain these things to us, he adds.
Using the Keck telescope in Hawaii, Marcys team also detected a second planet orbiting
the same star HD168443. The planet has about seven Jovian Masses. Astronomers infer
a planets existence by detecting the tiny wobble in the star that is generated by the planets
gravitational tug.
In a separate search, Marcy and Butler found the first planets orbiting a red dwarf star,
common type of star about one-third the mass of the sun. Studying the red dwarf Gliese
876, they discovered one planet with twice the mass of Jupiter, and another with about
one-half Jupiters mass. The new discoveries bring to 59 the number of extrasolar planets
identified.