When Susan Terebey used the Hubble Space Telescope to study a star called TMR-1 in the constellation Taurus some 450 light-years from Earth, she hoped to find a disk of dust around the young staroevidence, perhaps, of a nascent solar system. Instead Terebey, an astronomer at the Extrasolar Research Corporation in Pasadena, found what might be the first planet ever directly observed outside our solar system. tmr-1 turned out to be a double star, with the two sun-size stars some 3.7 billion miles apart. A thin filament of gas appears to extend away from the stars. And at the filament's end is a faint dot. "Just looking at this picture and knowing that there were two young stars in the middle suggested to me immediately that this was an escaped object," Terebey says. Based on its faintness and its presumed association with the two young stars, Terebey believes her object is a planet with two to three times Jupiter's mass, flung off in a gravitational tug-of-war between the stars. It is now racing away from them at about 20,000 miles an hour. Terebey concedes the object might be a rogue brown dwarf star or even an unrelated background star. She hopes future observations with the Keck telescope in Hawaii will solve the enigma.