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The Bimodal Color Distribution of Small Kuiper Belt Objects

Wong, Ian and Brown, Michael E. (2017) The Bimodal Color Distribution of Small Kuiper Belt Objects. Astronomical Journal, 153 (4). Art. No. 145. ISSN 0004-6256. doi:10.3847/1538-3881/aa60c3.

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We conducted a two-night photometric survey of small Kuiper Belt objects (KBOs) near opposition using the wide-field Hyper Suprime-Cam instrument on the 8.2 m Subaru Telescope. The survey covered about 90 deg^2 of sky, with each field imaged in the g and i bands. We detected 356 KBOs, ranging in absolute magnitude from 6.5 to 10.4. Filtering for high-inclination objects within the hot KBO population, we show that the g − i color distribution is strongly bimodal, indicative of two color classes—the red and very red subpopulations. After categorizing objects into the two subpopulations by color, we present the first dedicated analysis of the magnitude distributions of the individual color subpopulations and demonstrate that the two distributions are roughly identical in shape throughout the entire size range covered by our survey. Comparing the color distribution of small hot KBOs with that of Centaurs, we find that they have similar bimodal shapes, thereby providing strong confirmation of previous explanations for the attested bimodality of Centaurs. We also show that the magnitude distributions of the two KBO color subpopulations and the two color subpopulations observed in the Jupiter Trojans are statistically indistinguishable. Finally, we discuss a hypothesis describing the origin of the KBO color bimodality based on our survey results.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wong, Ian0000-0001-9665-8429
Brown, Michael E.0000-0002-8255-0545
Additional Information:© 2017. The American Astronomical Society. Received 2016 October 18; revised 2017 January 18; accepted 2017 February 8; published 2017 March 9. This research was supported by Grant NNX09AB49G from the NASA Planetary Astronomy Program and by the Keck Institute for Space Studies.
Group:Keck Institute for Space Studies, Astronomy Department
Funding AgencyGrant Number
Keck Institute for Space Studies (KISS)UNSPECIFIED
Subject Keywords:Kuiper belt: general – minor planets, asteroids: general
Issue or Number:4
Record Number:CaltechAUTHORS:20170308-160906890
Persistent URL:
Official Citation:Ian Wong and Michael E. Brown 2017 AJ 153 145
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74945
Deposited By: George Porter
Deposited On:09 Mar 2017 16:15
Last Modified:15 Nov 2021 16:29

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