A Caltech Library Service

Hubble Ultraviolet Spectroscopy of Jupiter Trojans

Wong, Ian and Brown, Michael E. and Blacksberg, Jordana and Ehlmann, Bethany L. and Mahjoub, Ahmed (2019) Hubble Ultraviolet Spectroscopy of Jupiter Trojans. Astronomical Journal, 157 (4). Art. No. 161. ISSN 1538-3881. doi:10.3847/1538-3881/ab0e00.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present the first ultraviolet spectra of Jupiter Trojans. These observations were carried out using the Space Telescope Imaging Spectrograph on the Hubble Space Telescope and cover the wavelength range 200–550 nm at low resolution. The targets include objects from both of the Trojan color subpopulations (less-red and red). We do not observe any discernible absorption features in these spectra. Comparisons of the averaged UV spectra of less-red and red targets show that the subpopulations are spectrally distinct in the UV. Less-red objects display a steep UV slope and a rollover at around 450 nm to a shallower visible slope, whereas red objects show the opposite trend. Laboratory spectra of irradiated ices with and without H_2S exhibit distinct UV absorption features; consequently, the featureless spectra observed here suggest H_2S alone is not responsible for the observed color bimodality of Trojans, as has been previously hypothesized. We propose some possible explanations for the observed UV-visible spectra, including complex organics, space weathering of iron-bearing silicates, and masked features due to previous cometary activity.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Wong, Ian0000-0001-9665-8429
Brown, Michael E.0000-0002-8255-0545
Ehlmann, Bethany L.0000-0002-2745-3240
Mahjoub, Ahmed0000-0003-1229-5208
Additional Information:© 2019. The American Astronomical Society. Received 2018 December 19; revised 2019 February 20; accepted 2019 March 6; published 2019 April 2. The experimental portion of this work was conducted at the Jet Propulsion Laboratory, Caltech, under a contract with the National Aeronautics and Space Administration (NASA) and at the Caltech Division of Geological and Planetary Sciences. This work was supported in part by the Keck Institute for Space Studies (KISS). I.W. is supported by a Heising-Simons Foundation 51 Pegasi b postdoctoral fellowship. The authors also thank Amanda Hendrix for providing helpful referee comments that improved the manuscript.
Group:Keck Institute for Space Studies, Astronomy Department
Funding AgencyGrant Number
Keck Institute for Space Studies (KISS)UNSPECIFIED
Heising-Simons FoundationUNSPECIFIED
Subject Keywords:minor planets, asteroids: general; techniques: spectroscopic
Issue or Number:4
Record Number:CaltechAUTHORS:20190401-084307776
Persistent URL:
Official Citation:Ian Wong et al 2019 AJ 157 161
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:94310
Deposited By: George Porter
Deposited On:01 Apr 2019 16:28
Last Modified:16 Nov 2021 17:04

Repository Staff Only: item control page