Collision detection issues

I'm creating a space game where the main player unit is a stationary object that fires a laser.

I've added planets to the environment and want the lasr to 'break' on contact with the planets.

So far everything works, but the laser is breaking on a box surrounding each planet and not the planets themselves.

I think the issue is here on my checkCollisions function.

private function checkCollisions(testX:Number, testY:Number):Boolean

        {

            var i:int;

            var len:int = _planets.length;

            for (i = 0; i < len; i++)

            {

                if (MovieClip(_planets).hitTestPoint(testX, testY, true))

                {

                    return true;

                    break;

                }

            }

            return false;

        }