Observations of black hole-neutron star ( BH-NS ) mergers via gravitational waves ( GWs ) are of great interest for their electromagnetic counterparts , such as short gamma-ray bursts , and could provide crucial information on the nature of BHs and the NS crust and magnetosphere .
While no event has been confirmed , a recent possible detection of a BH-NS merger event by the LIGO-Virgo collaboration has attracted a lot of attention to these sources .
In this second paper of the series , we follow-up our study of the dynamical evolution of triples comprised of an inner BH-NS binary .
In particular , we examine how the progenitor metallicity affects the characteristics of the BH-NS mergers in triples .
We determine the distributions of masses , orbital parameters and merger times , as a function of the progenitor metallicity and initial triple orbital distributions , and show that the typical eccentricity in the LIGO band is \sim 10 ^ { -2 } -10 ^ { -1 } .
We derive a merger rate range of \Gamma _ { \mathrm { BH - NS } } = 1.9 \times 10 ^ { -4 } -22 \mathrm { Gpc } ^ { -3 } \mathrm { yr } ^ { % -1 } , consistent the LIGO-Virgo upper limit .
Finally , we study the expected spin-orbit misalignments of merging BH-NS binaries from this channel , and find that typically the effective spin distribution is peaked at { \chi _ { eff } } \sim 0 with significant tails .