A Circumbinary Planet is an Extra Solar Planet orbiting both stars of
The first such system was identified in 2003 and
as of 2014, about 15 identifications have been confirmed.
The orbit of such a planet must be beyond a certain
Critical Radius or Radius Of Stability to remain
stable, generally at least 2-4 times the Semi-Major Axis (a)
of the stars' orbits.