Lost in Space: Companions’ Fatal Dance around Massive Dying Stars

Abstract

Abstract Discoveries of planet and stellar remnant hosting pulsars challenge our understanding, as the violent supernova explosion that forms the pulsar presumably destabilizes the system. Type II supernova explosions lead to the formation of eccentric bound systems, free-floating planets, neutron stars, pulsars, and white dwarfs. Analytical and numerical studies of high mass-loss rate systems based on perturbation theory so far have focused mainly on planet-star systems. In this paper, we extend our understanding of the fate of planet-star and binary systems by assuming a homologous envelope expansion model using a plausible ejection velocity (1000–10,000 km s−1), and envelope and neutron star masses. The investigation covers secondary masses of 1–10 M J for planetary companions and 1–20 M ⊙ for stellar companions. We conduct and analyze over 2.5 million simulations assuming different semimajor axes (2.23–100 au), eccentricities (0–0.8), and true anomalies (0–2π) for the companion. In a homologous expansion scenario, we confirm that the most probable outcome of the explosion is the destabilization of the system, while the retention of a bound system requires a highly eccentric primordial orbit. In general, a higher ejecta velocity results in a lower eccentricity orbit independent of secondary mass. The explanation of close-in pulsar planets requires exotic formation scenarios, rather than survival through the type II supernova explosion model. Postexplosion bound star systems gain a peculiar velocity (<100 km s−1), even though the explosion model is symmetric. The applied numerical model allows us to derive velocity components for dissociating systems. The peculiar velocities of free-floating planets and stellar corpses are in the range of 10−6–275 km s−1.