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1I/2017 U1 (‘Oumuamua) is Hot: Imaging, Spectroscopy, and Search of Meteor Activity

Ye, Quan-Zhi and Zhang, Qicheng and Kelley, Michael S. P. and Brown, Peter G. (2017) 1I/2017 U1 (‘Oumuamua) is Hot: Imaging, Spectroscopy, and Search of Meteor Activity. Astrophysical Journal Letters, 851 (1). Art. No. L5. ISSN 2041-8213. doi:10.3847/2041-8213/aa9a34.

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1I/2017 U1 ('Oumuamua), a recently discovered asteroid in a 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 Palomar Hale Telescope as well as a search of meteor activity potentially linked to this object using the Canadian Meteor Orbit Radar. We find that 'Oumuamua exhibits a moderate spectral gradient of 10% ± 6% (100 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 observation and spectral line analysis show no evidence that 'Oumuamua is presently active. Negative meteor observation is as expected, since ejection driven by sublimation of commonly known cometary species such as CO requires an extreme ejection speed of ~40 m s^(−1) at ~100 au in order to reach the Earth. No obvious candidate stars are proposed as the point of origin for 'Oumuamua. Given a mean free path of ~10^9 ly in the solar neighborhood, 'Oumuamua has likely spent a very long time in interstellar space before encountering the solar system.

Item Type:Article
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URLURL TypeDescription Paper
Ye, Quan-Zhi0000-0002-4838-7676
Zhang, Qicheng0000-0002-6702-191X
Kelley, Michael S. P.0000-0002-6702-7676
Additional Information:© 2017 The American Astronomical Society. Received 2017 November 7; revised 2017 November 9; accepted 2017 November 10; published 2017 December 5. We thank an anonymous reviewer for rapid comments, Nadia Blagorodnova for kindly sharing her Palomar observation time with us and helping with the observation, Joe Masiero for helping us understand the operation of the Hale Telescope, as well as Kajsa Peffer and Paul Nied for observational support. Q.-Z. is supported by the GROWTH project (National Science Foundation grant No. 1545949). This research makes use of observations from the Hale Telescope at Palomar Observatory, which is owned and operated by Caltech and administered by Caltech Optical Observatories, as well as data and services provided by the International Astronomical Union's Minor Planet Center. Funding support from the NASA Meteoroid Environment Office (cooperative agreement NNX15AC94A) for CMOR operations is gratefully acknowledged. Facilities: CMOR - , Hale (LFC and DBSP) - . Software: Astropy (Astropy Collaboration et al. 2013), IRAF (Tody 1986).
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
Subject Keywords:local interstellar matter – meteorites, meteors, meteoroids – minor planets, asteroids: individual (1I/2017 U1 (‘Oumuamua))
Issue or Number:1
Record Number:CaltechAUTHORS:20171206-104856090
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Official Citation:Quan-Zhi Ye et al 2017 ApJL 851 L5
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83727
Deposited By: Tony Diaz
Deposited On:06 Dec 2017 23:40
Last Modified:15 Nov 2021 20:13

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