1I/'Oumuamua is Hot: Imaging, Spectroscopy and Search of Meteor Activity [EPA]


1I/2017 U1 (‘Oumuamua), a recently discovered asteroid in hyperbolic orbit, is likely the first macroscopic object of extrasolar origin identified in the solar system. Here, we present imaging and spectroscopic observations of ‘Oumuamua using the Hale Telescope as well as a search of meteor activity potentially linked to this object. We find that ‘Oumuamua exhibits a moderate spectral gradient of $10\%\pm6\%~(100~\mathrm{nm})^{-1}$, a value significantly lower than that of outer solar system bodies, indicative of a formation and/or previous residence in a warmer environment. Imaging, spectral and meteor observations show no evidence that ‘Oumuamua is presently or has been recently active. No obvious candidate stars are proposed as the point of origin for ‘Oumuamua. Given a mean free path of $\sim10^9$~ly in the solar neighborhood, ‘Oumuamua has likely spent a very long time in the interstellar space before encountering the solar system.

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Q. Ye, Q. Zhang, M. Kelley, et. al.
Wed, 8 Nov 17

Comments: Submitted to ApJ Letters