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Will one or more additional interstellar asteroids be detected by 2019?
The astronomical community, and increasingly, the broader public, have been abuzz over the recent passage of an interstellar asteroid through the solar system. The interloping object, now officially known as 'Oumuamua (Hawaiian for "messenger from the distant past") was discovered by the PanSTARRS monitoring system on October 19th, 2017. It was quickly confirmed to have a strongly hyperbolic trajectory (with heliocentric velocity v~26 km/sec at infinity), and follow-up observations (see also, here) show that it has a rotation period of roughly seven hours, a reddish overall color, and a highly elongated overall shape. Assuming that 'Oumuamua has low reflectivity, its long axis is approximately 400m, and its mass is of order a billion kilograms. Curiously, no sign of coma has been detected, indicating that volatiles such as water ice are not exposed on its surface. These unusual properties have sparked speculation that `Oumuamua is a directed interstellar probe, and various SETI-related efforts are underway to examine it.
The detection of `Oumuamua in the face of various observational biases suggests that such objects may pervade the Galaxy, with a number density estimated to be of order one per ten cubic astronomical units. We therefore ask: Prior to January 1, 2019, will one or more additional interstellar objects be observed passing within a sphere of radius 50 AU centered on the Sun?
In order for this question to resolve positively, a newly discovered interstellar object must either, 1. be reported in a peer-reviewed journal as having a hyperbolic orbit (eccentricity, e>1) prior to crossing a sphere of 50AU radius centered on the Sun, or 2. receive an "I" designation from the IAU Minor Planet Center, or both.
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