Mitchell Institute for Fundamental Physics & Astronomy
College Station, Texas 77843
Gravitational-wave observations of merging black holes and merging neutron stars have significantly impacted our understanding of the formation and evolution of compact-object binaries. One of the most pressing uncertainties in how double neutron stars form is the common-envelope phase, whereby a neutron star inspirals within the envelope of a massive star in order to tighten the orbit and eventually form a remnant compact binary. The large uncertainty of this pathway stems from its multiscale, multiphysics nature, making it computationally prohibitive to resolve all physical scales at once. As the catalog of merging compact binaries continues to grow, efforts to develop physically end-to-end models that can also be predictive are especially imperative. I will discuss the formation-pathway puzzles for compact binaries that have arisen from recent gravitational-wave observations. I will also present recent and ongoing work on modeling neutron-star accretion on compact-object scales that can eventually be used as sub-grid prescriptions for global common-envelope models.