1I/2017 (`Oumuamua): A Solar System Small-Body Analogue, or an Exotic Object?

1I/2017 (`Oumuamua), the first-detected interstellar interloper near the Earth, provided an unprecedented view of a small body that originated outside of the Solar nebula. Surprisingly, the large inferred Galactic population of similar objects from the detection of `Oumuamua at a geocentric distance of 0.16AU is in slight tension with current models of planetesimal production in protoplanetary disks. Furthermore, `Oumuamua’s physical and dynamical properties do not fit within the current astronomical taxonomy and may demand an explanation outside of conventional avenues of exoplanetary system formation. One such interpretation is that `Oumuamua contained a component of molecular hydrogen ice. In this presentation, we discuss the compatibility of this substance with observations of `Oumuamua and examine the feasibility of building these objects. We focus on the starless cores of Giant Molecular Clouds, the only known environments which could reach the frigid conditions necessary for hydrogen ice deposition. Via energy balances arguments, simple analytic and numerical models of accretion, and the classic Kolmogorov framework of turbulence, we characterize the possibilities for growth and barriers to assembly in size regimes ranging from micron-sized dust to required kilometer-scale progenitors of `Oumuamua. Finally, we provide predictions on interstellar objects relevant to the Vera Rubin Observatory.