1I/Oumuamua is the first known interstellar small body, probably being only about 100~m in size. Against expectations based on comets, Oumuamua does not
show any activity and has a very elongated figure, and also exhibits undamped
rotational tumbling. In contrast, Oumuamua's trajectory indicates that it was moving with the local stars, as expected from a low-velocity ejection from a relatively nearby system. Here I assume that Oumuamua is typical of 100-m
interstellar objects, and speculate on its origins. I find that giant planets
are relatively inefficient at ejecting small bodies from inner solar systems of
main-sequence stars, and that binary systems offer a much better opportunity
for ejections of non-volatile bodies. I also conclude that Oumuamua is not a member of a collisional population, which could explain its dramatic difference from small asteroids. I observe that 100-m small bodies are expected to carry little mass in realistic collisional populations, and that occasional events when whole planets are disrupted in catastrophic encounters may dominate interstellar population of 100-m fragments. Unlike the Sun or Jupiter, red dwarf stars are very dense and are capable of thoroughly tidally disrupting terrestrial planets. I conclude that the origin of Oumuamua as a fragment from
a planet that was tidally disrupted and then ejected by a dense member of a
binary system could explain its peculiarities.

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