Seminar

An origins story for 'Oumuamua, the "cigar from another star"

The first interstellar object, 'Oumuamua, was discovered passing through the Solar System on a hyperbolic orbit. It has several peculiar features: a very stretched-out shape, a tumbling rotation, and an absence of outgassing during its close approach to the Sun despite having colors similar to volatile-rich Solar System bodies. I will discuss the origins of 'Oumuamua. I will propose that it is likely an extinct fragment of a comet-like planetesimal born in a planet-forming disk that also formed Neptune- to Jupiter-mass giant planets. Before being ejected from its host system, ’Oumuamua’s parent body underwent a close encounter with a giant planet and was tidally disrupted into small pieces, similar to comet Shoemaker-Levy 9’s disruption after passing close to Jupiter. After disruption, fragments underwent numerous close passages to their host stars and lost their surface volatiles. This model can match most of 'Oumuamua's peculiarities, although its extreme shape remains unexplained.

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