A planet is in a circular orbit around a massive star. The star undergoes a spherically symmetric explosion in which one per cent of its mass is suddenly ejected to a distance (a) Find the eccentricity of the new orbit of the planet, assuming the planet itself is (b) How much mass would the star have to lose for the planet to become unbound and a well beyond that of the planet's orbit. otherwise unaffected by the explosion. "runaway" planet?