Earth mass
Where "k" is a factor related that can be expressed by Love numbers, taking into considerations non-uniformity in the planet mass density; corrections due to planet rigidity, neglected above, also enter here. For Earth, most of the bulge is made of sea water and has no correction for rigidity, but its mass density is 0.18 the average Earth mass density (1 g/cm3 vs. 5.5 g/cm3), so formula_15. The literature uses a close value of 0.2 (formula_16 )