Its thought planets in general form out of the disks of gas and debris that surround many young stars. One model for how gas giants form is called gravitational instability, in which a perturbation in the disk causes a clump of material to suddenly coalesce into a gassy planet.

　　The other model is core accretion, in which material first clumps into a rocky core, and the core then gravitationally gathers nearby gases.

　　According to Maroiss team, the problem with such widespread gas giants is that they all couldnt have formed the same way. Too far from the star and theres not enough gas for core accretion to work, but too close and its too hot for debris to become gravitationally unstable.

　　The system is either just too young and the planets are just too far away and dont have time to form before the gas in the disk is depleted, or they are too close and the disk is too warm to form planets, Marois said.

　　Gas giant planets have been found in orbits close to their parent stars, sometimes even closer than Mercury is to the sun. In these cases, many experts believe the so-called hot Jupiters may have formed farther away from their stars and then migrated closer over time.

　　That is one possible way out in explaining the problem. There is probably more to it than thatbut this will require more work, Marois said.

　　But the fact that we are seeing this planetary system at this early stage of evolution is definitely giving us insight on what happened to arrive at its current configuration.

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