1I/‘Oumuamua as an N ₂ Ice Fragment of an Exo?Pluto Surface II: Generation of N ₂ Ice Fragments and the Origin of ‘Oumuamua

The origin of the interstellar object 1I/‘Oumuamua has defied explanation. In a companion paper (Jackson & Desch, 2021), we show that body N2 ice with axes 45 m × 44 7.5 at time observation would be consistent its albedo, nongravitational acceleration, and lack observed CO or CO2 dust. Here demonstrate impacts on surfaces Pluto-like Kuiper belt objects (KBOs) have generated ejected ?1014 collisional fragments—roughly half them H2O fragments fragments—due to dynamical instability depleted primordial belt. We consistency between these numbers frequency which observe like 1I/‘Oumuamua, more comet-like 2I/Borisov, if other stellar systems eject such efficiency Sun; infer differentiated KBOs instabilities impact-generated may near-universal among extrasolar systems. Galactic cosmic rays erode over 4.5 Gyr, so are small fraction (?0.1%) long-period Oort comets, but C/2016 R2 an example. estimate ‘Oumuamua was about 0.4–0.5 Gyr ago, from young (?108 yr) system, speculate in Perseus arm. Objects directly probe surface compositions hitherto-unobserved type exoplanet: “exo-Plutos.” first sample exoplanet brought us.