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The color-magnitude distribution of small Jupiter Trojans

Wong, Ian and Brown, Michael E. (2015) The color-magnitude distribution of small Jupiter Trojans. Astronomical Journal, 150 (6). Art. No. 174. ISSN 1538-3881. doi:10.1088/0004-6256/150/6/174.

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We present an analysis of survey observations targeting the leading L4 Jupiter Trojan cloud near opposition using the wide-field Suprime-Cam CCD camera on the 8.2 m Subaru Telescope. The survey covered about 38 deg2 of sky and imaged 147 fields spread across a wide region of the L4 cloud. Each field was imaged in both the g' and the i' band, allowing for the measurement of g − i color. We detected 557 Trojans in the observed fields, ranging in absolute magnitude from H = 10.0 to H = 20.3. We fit the total magnitude distribution to a broken power law and show that the power-law slope rolls over from 0.45 ± 0.05 to 0.36_(-0.09)^(+0.05) at a break magnitude of H_b = 14.93_(-0.88)^(+0.73). Combining the best-fit magnitude distribution of faint objects from our survey with an analysis of the magnitude distribution of bright objects listed in the Minor Planet Center catalog, we obtain the absolute magnitude distribution of Trojans over the entire range from H = 7.2 to H = 16.4. We show that the g − i color of Trojans decreases with increasing magnitude. In the context of the less-red and red color populations, as classified in Wong et al. using photometric and spectroscopic data, we demonstrate that the observed trend in color for the faint Trojans is consistent with the expected trend derived from extrapolation of the best-fit color population magnitude distributions for bright cataloged Trojans. This indicates a steady increase in the relative number of less-red objects with decreasing size. Finally, we interpret our results using collisional modeling and propose several hypotheses for the color evolution of the Jupiter Trojan population.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wong, Ian0000-0001-9665-8429
Brown, Michael E.0000-0002-8255-0545
Additional Information:© 2015. The American Astronomical Society. Received 2015 July 27; accepted 2015 October 11; published 2015 November 9. This research was supported by Grant NNX09AB49G from the NASA Planetary Astronomy Program and by the Keck Institute for Space Studies. The authors also thank an anonymous reviewer for constructive comments that helped to improve the manuscript.
Group:Keck Institute for Space Studies, Division of Geological and Planetary Sciences
Funding AgencyGrant Number
Keck Institute for Space Studies (KISS)UNSPECIFIED
Subject Keywords:minor planets, asteroids: general
Issue or Number:6
Record Number:CaltechAUTHORS:20160108-121610380
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Official Citation:Ian Wong and Michael E. Brown 2015 The Astronomical Journal 150 174
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:63510
Deposited By: Ruth Sustaita
Deposited On:09 Jan 2016 02:11
Last Modified:10 Nov 2021 23:17

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