3D hydrodynamic simulations of white dwarf-main-sequence star collisions - II. Off-centre collisions

Stellar collisions have garnered renewed attention for their role in the formation of peculiar objects, such as blue stragglers, and their potential to explain transients with atypical observational and spectroscopic signatures. Among these, white dwarf-main sequence (WD-MS) collisions are particularly intriguing due to the diverse evolutionary pathways they can produce - such as peculiar red giants, novae, or sub-Chandrasekhar supernovae. We present 3D smoothed particle hydrodynamics (SPH) simulations of WD-MS collisions, exploring a range of mass ratios and impact parameters. We analyze the dynamics, energetics, gas morphology, and mass-loss from these interactions. Using a 34-isotope nuclear network, we further predict the nucleosynthesis products generated during these collisions. Our models suggest that at early times the ejecta have a bipolar structure and, along with the stellar remnant, may be enriched in isotopes such as C-13, N-15, and O-17. In the case of near head-on collisions, the ejecta may also show an overabundance of Li-7 relative to solar values.