Figure 7

Figure 7: Mass-shedding indicator ( ∂(lnh)) (∂(lnh)) χ ≡ ∂r eq∕ ∂r pole vs. orbital frequency M0 Ω, where h is the fluid enthalpy and the derivative is measured at the NS surface in the equatorial plane toward the companion and toward the pole in the direction of the angular momentum vector, for a series of QE NS-NS sequences assuming equal-mass components. Here, χ = 1 corresponds to a spherical NS, while χ = 0 indicates the onset of mass shedding. More massive NSs are more compact, and thus able to reach smaller separations and higher angular frequencies before mass shedding gets underway. Image reproduced by permission from Figure 19 of [305], copyright by AAS.