Presentation #505.03 in the session “Interstellar Objects”.
1I/2017 U1 (ʻOumuamua), the first-detected macroscopic interstellar interloper near the Earth, provided an unprecedented view of a small body that originated outside of the Solar nebula. Surprisingly, ʻOumuamua’s unique attributes do not fit neatly within the current categorization of small bodies. Currently, there exists no consensus in the astronomical community regarding either the bulk composition or the formation mechanism for this object. In this presentation, we assess the merits of the various interpretations that have been suggested to explain ʻOumuamua’s observed non-Keplerian trajectory with the non-detection of traditional cometary volatiles. Specifically, we attempt to reconcile the leading hypotheses on the nature of ʻOumuamua with the implied reservoir of similar objects from its detection by Pan-STARRS. By developing a general framework to quantify the population of interstellar objects from a given interpretation, we can directly compare the various proposed formation histories. We consider two exotic ices, hydrogen and nitrogen, as well as compositions attributing ʻOumuamua’s non-gravitational acceleration to solar radiation pressure. While we conclude that none of these interpretations are perfectly satisfactory, we make predictions that will be testable by the Vera Rubin Observatory to resolve the tension introduced by ʻOumuamua.