http://arxiv.org/abs/1712.06721
The first confirmed interstellar interloper in our Solar System, 1I/
Oumuamua, is likely to be a minor body ejected from another star, but its brief flyby and faintness made it difficult to study. Two remarkable properties are its large (2-2.5 mag) rotational variability and its motion relative to the Sun before encounter. The former suggests an extremely elongated (>10:1) shape and the latter an origin from the protoplanetary disk of a young star in a nearby association. 1I/Oumuamua’s variability can also be explained if it is a contact binary of near-equilibrium ellipsoidal components and heterogeneous surfaces, i.e. brighter, dust-mantled inner-facing hemispheres and darker, dust-free outer-facing poles. The probability that 1I/Oumuamua has the same motion as a young stellar association is <1%. One explanation for the youth of 1I/Oumuamua relative to the Solar neighborhood mean it that loss of dust mantles and darkening of lag surfaces by cosmic rays renders similar objects undetectable in a few 100’s of Myr. In this scenario, 1I/`Oumuamua is smaller and much less massive, but represents a more numerous population of ejected planetesimals. Studies of such objects are a potential means to probe early planet formation, complementing observations of protoplanetary disks and studies of meteorites.
E. Gaidos
Wed, 20 Dec 17
72/83
Comments: submitted to MNRAS
You must be logged in to post a comment.