Astronomers have discovered massive gas giant planets like Jupiter orbiting their stars in other solar systems at closer than 0.7 (about the distance of Venus's orbit). Why don't astronomers believe that these gas giant planets originally formed at these locations?
O There were too many terrestrial planets already formed at these distances - too crowded.
O Planetessimals could not have collided and clumped together to form protoplanets this close to a star.
O The planets' gravity would have been too large to form that close to the star.
O Their orbital periods are too long for them to be located that close to their companion stars.
O The temperature in the early solar system was too high at these distances.