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2004 EW_(95): A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt

Seccull, Tom and Fraser, Wesley C. and Puzia, Thomas H. and Brown, Michael E. and Schönebeck, Frederik (2018) 2004 EW_(95): A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt. Astrophysical Journal Letters, 855 (2). Art. No. L26. ISSN 2041-8213. doi:10.3847/2041-8213/aab3dc.

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Models of the Solar System's dynamical evolution predict the dispersal of primitive planetesimals from their formative regions among the gas-giant planets due to the early phases of planetary migration. Consequently, carbonaceous objects were scattered both into the outer asteroid belt and out to the Kuiper Belt. These models predict that the Kuiper Belt should contain a small fraction of objects with carbonaceous surfaces, though to date, all reported visible reflectance spectra of small Kuiper Belt Objects (KBOs) are linear and featureless. We report the unusual reflectance spectrum of a small KBO, (120216) 2004 EW_(95), exhibiting a large drop in its near-UV reflectance and a broad shallow optical absorption feature centered at ~700 nm, which is detected at greater than 4σ significance. These features, confirmed through multiple epochs of spectral photometry and spectroscopy, have respectively been associated with ferric oxides and phyllosilicates. The spectrum bears striking resemblance to those of some C-type asteroids, suggesting that 2004 EW_(95) may share a common origin with those objects. 2004 EW95 orbits the Sun in a stable mean motion resonance with Neptune, at relatively high eccentricity and inclination, suggesting it may have been emplaced there by some past dynamical instability. These results appear consistent with the aforementioned model predictions and are the first to show a reliably confirmed detection of silicate material on a small KBO.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Seccull, Tom0000-0001-5605-1702
Fraser, Wesley C.0000-0001-6680-6558
Puzia, Thomas H.0000-0003-0350-7061
Brown, Michael E.0000-0002-8255-0545
Alternate Title:2004 EW95: A Phyllosilicate-bearing Carbonaceous Asteroid in the Kuiper Belt
Additional Information:© 2018. The American Astronomical Society. Received 2018 January 29; revised 2018 March 2; accepted 2018 March 3; published 2018 March 15. We thank Faith Vilas and Alan Fitzsimmons for their encouraging constructive discussion and comments. This work is based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programs 093.C-0259(A), 095.C-0521(A) and 099.C-0651(A). W.C.F. acknowledges support from STFC grant ST/P0003094/1. T.H.P. acknowledges support through the FONDECYT Regular project No. 1161817 and the BASAL Center for Astrophysics and Associated Technologies (PFB-06). M.E.B. acknowledges support from the NASA Planetary Astronomy Program through grant NNX09AB49G. Facility: ESO VLT(X-Shooter and FORS2) - . Software: Astropy (The Astropy Collaboration et al. 2013) corner (Foreman-Mackey 2016) emcee (Foreman-Mackey et al. 2013) ESO Reflex (Freudling et al. 2013) matplotlib (Hunter 2007) numpy (van der Walt et al. 2011) scipy (Jones et al. 2001).
Group:Astronomy Department
Funding AgencyGrant Number
European Southern Observatory (ESO)093.C-0259(A)
European Southern Observatory (ESO)095.C-0521(A)
European Southern Observatory (ESO)099.C-0651(A)
Science and Technology Facilities Council (STFC)ST/P0003094/1
Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT)1161817
Subject Keywords:Kuiper belt objects: individual (2004 EW95) ; minor planets, asteroids: general; techniques: photometric; techniques: spectroscopic
Issue or Number:2
Record Number:CaltechAUTHORS:20180328-133307174
Persistent URL:
Official Citation:Tom Seccull et al 2018 ApJL 855 L26
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:85478
Deposited By: George Porter
Deposited On:28 Mar 2018 23:21
Last Modified:15 Nov 2021 20:29

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