text:   persisting planetesimals",7,"['New paper! In work led by @sraymond_astro, with Nathan Kaib and @jjfplanet, we quantify how planetesimals ejected from the Solar System differ from those that survive as small bodies in reservoirs such as the Kuiper belt and Oort Cloud.\n\n<LINK>', ""Interstellar objects are the motivation. Only two are known. 'Oumuamua was small, irregularly shaped, and generally weird. Borisov was pretty boringly similar to Solar System comets. A sample of two is a thin gruel, but it's better than one! And there will be (many) more."", ""The unexpected properties of 'Oumuamua inspired many novel ideas. It might be a hydrogen iceberg (Seligman &amp; Laughlin), an ultra-porous aggregate (Moro-Martin), a planet tidally disrupted by a star or compact object (Cuk, Rafikov, Zhang and Lin), etc..."", 'To assess these possibilities, our goal was to understand the null hypothesis: what would planetesimals ejected from Solar System-like planetary systems look like? To do this, we tracked the fates of ~18,000 planetesimals in constrained realizations of the early Solar System.', ""We were particularly interested in planetesimals that passed so close to planets that they would be tidally disrupted (and shredded into small pieces), or which got close enough to the Sun that their surfaces might have dried out. These could be 'Oumuamua-like."", 'The result? The frequency of volatile loss is far higher for ejected planetesimals than for surviving ones. Even if all interstellar objects were ejected from Solar System-like systems, their physical properties should be more diverse than those of Solar System survivors.', 'Of course, we know that not all planetary systems resemble the Solar System. As more interstellar objects are found, the goal will be to identify both the truly primordial bodies, and those that have been altered, and link them to known exoplanet populations.']",20,10,1842