Chirp mass ($\mathcal{M}=(m_1{m}_2{)}^{3/5}/(m_1+m_2{)}^{1/5}$)

The chirp mass is the combination of two component masses controlling the leading Newtonian binary chirp. Inverting its frequency equation givesUse $f$ in hertz and $\dot{f}$ in hertz per second to obtain kilograms. For equal component masses $m$, $\mathcal{M}=m/2^{1/5}$. A stipulated $20+20$ solar mass system therefore has $\mathcal{M}\approx 17.411$ solar masses. In a cosmological observation the time and frequency measured at the detector instead yield $(1+z){\mathcal{M}}_{\mathrm{source}}$, where $z$ is redshift; phase evolution alone does not independently determine the source mass and redshift.