  We have detected 2 circumbinary planets around the close binary system NN
Serpentis using the orbital time delay effect measured via the sharp eclipses
of the white dwarf primary. The present pre-cataclysmic binary was formed when
the original - 2 M primary expanded into a red giant, causing the secondary
star to drop from its original orbit at a separation of about 1.4 A.U. down to
its current separation at 0.0043 A.U. A quasi-adiabatic evolution of the
circumbinary planets' orbits during the common-envelope phase would have placed
them in unstable configurations, suggesting that they may have suffered
significant orbital drag effects and were originally in much larger orbits.
Alternatively, they may have been created as 2nd-generation planets during the
last million years from the substantial amount of material lost during the
creation of the binary, making them the youngest planets known. Either solution
shows how little we actually understand about planetary formation.
