Classical Mechanics (Kibble & Berkshire) · Problem 10.20
The angular momentum principle — T.W.B. Kibble, F.H. Berkshire
Physics — Mechanics · two-body-problem-scattering
Problem
Binary star The observed period of the binary star Cygnus X-1 (of which only one component is visible) is 5.6 days, and the semi-major axis of the orbit of the visible component is about 0.09 AU. The mass of the visible component is believed to be about 20M⊙. Estimate the mass of its dark companion. [Requires the numerical solution of a cubic equation.]