A．Because scientists cannot figure out what they can be．
B．Because astronomers have never seen similar orbiting pattern and size before．
C．Because the planets are very huge．
D．Because the planets are far from our solar system．
A．other stars have planets more or less like the one going around the sun
B．other stars have planets with bigger orbits
C．the way planets orbiting around the sun in our solar system is quite unique
D．planets in other systems have elongated orbits
A．it is either a star or a planet
B．it was formed like a star and orbits like a planet
C．it helps us change the definition of"planet"
D．it cannot be explained satisfactorily by conventional theory
A．New Planetary Puzzlers
B．"Hot Jupiters" Challenging Conventional Theory
C．A Redefinition of"Planet"
D．Two Remarkable Finds