calc_q

luminet.black_hole_math.calc_q(p: float, bh_mass: float) → float

Convert periastron \(P\) to \(Q\)

The variable \(Q\) has no explicit physical meaning, but makes many equations more readable.

\[Q = \sqrt{(P - 2M)(P + 6M)}\]

Parameters:

• periastron (float) – Periastron distance

• bh_mass (float) – Black hole mass

Returns:

float – \(Q\)