OK, suppose as proposed that the H2 in an object couldn't survive the journey. What makes us certain that Oumu is interstellar? Haven't seen that convincing arg

OK, suppose as proposed that the H2 in an object couldn't survive the journey. What makes us certain that Oumu is interstellar? Haven't seen that convincing argument (in human-readable form). Voyagers I and II are leaving the solar system; they got the kinetic energy to do that. I'm not convinced that all plausible histories for that happening within the SS without human assistance have been explored. As for the makeup of the object ... that will remain hypothetical. Maybe if we'd seen it sooner ...