Around the star Kepler-11 (mass 0.95 solar masses), there are orbiting six planets, at i) 0.0911, ii) 0.107, iii) 0.1542, iv) 0.1939, v) 0.2495, and vi) 0.464 AU.
a) How large is the Hill sphere for planet (i) if you consider the star-planet system?
b) How large is the Hill sphere if you consider the mutual pull of planets (i) and (ii)?
c) How long would the minimum-energy orbit take to get from planet (ii) to planet (i)?