Abstract : This is the 2nd of 4 papers describing a new planet and star formation theory. Currently there is no explanation for why planets form with particular masses. A number of models have been suggested, (for example the Nice[1] model and others), but these conflict both with conservation of momentum, and Kepler’s equations. This paper solves those problems, deriving a mass-equation mathematically, and then verifying with observed data. The paper will then go on to explain the formation of “Hot Jupiter” retrograde exoplanets[2], explain the formation of giant planets like Jupiter and Saturn in our own Solar System, and also put forward a hypothetical new class of Astronomical objects, “Dark Stars”[3], which can potentially revolutionise Astronomy. This paper will additionally identify 32 exosystems where life as we know it is likely to develop, and offer a potential explanation which removes the need for “Dark Matter” to exist. [1] Explained and challenged in this paper – see section 1.5 in this paper [2] Some 200 of these have been observed, and are currently substantially unexplained. [3] If this theory is correct, and these are observed, then it will avoid the need for “Dark Matter”.