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Composition of KBO (50000) Quaoar

Ore, C. Morea Dalle and Barucci, M. A. and Emery, J. P. and Cruikshank, D. P. and Ore, L. V. Dalle and Merlin, F. and Alvarez-Candal, A. and de Bergh, C. and Trilling, D. E. and Perna, D. and Fornasier, S. and Mastrapa, R. M. E. and Dotto, E. (2009) Composition of KBO (50000) Quaoar. Astronomy & Astrophysics, 501 (1). pp. 349-357. ISSN 1432-0746


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Publisher’s or external URL: http://dx.doi.org/10.1051/0004-6361/200911752


Aims. The objective of this work is to investigate the physical properties of objects beyond Neptune-the new frontiers of the Solar System-and in particular to study the surface composition of (50 000) Quaoar, a classical Transneptunian (or Kuiper Belt) object. Because of its distance from the Sun, Quaoar is expected to have preserved, to a degree, its original composition. Our goals are to determine to what degree this is true and to shed light on the chemical evolution of this icy body. Methods. We present new near-infrared (3.6 and 4.5 mu m) photometric data obtained with the Spitzer Space Telescope. These data complement high resolution, low signal-to-noise spectroscopic and photometric data obtained in the visible and near-infrared (0.4-2.3 mu m) at VLT-ESO and provide an excellent set of constraints in the model calculation process. We perform spectral modeling of the entire wavelength range-from 0.3 to 4.5 mu m by means of a code based on the Shkuratov radiative transfer formulation of the slab model. We also attempt to determine the temperature of H(2)O ice making use of the crystalline feature at 1.65 mu m. Results. We present a model confirming previous results regarding the presence of crystalline H(2)O and CH(4) ice, as well as C(2)H(6) and organic materials, on the surface of this distant icy body. We attempt a measurement of the temperature and find that stronger constraints on the composition are needed to obtain a precise determination. Conclusions. Model fits indicate that N(2) may be a significant component, along with a component that is bright at lambda > 3.3 mu m, which we suggest at this time could be amorphous H(2)O ice in tiny grains or thin grain coatings. Irradiated crystalline H(2)O could be the source of small-grained amorphous H(2)O ice. The albedo and composition of Quaoar, in particular the presence of N(2), if confirmed, make this TNO quite similar to Triton and Pluto.

Item Type: Article
Publisher’s Statement: Published by EDP Sciences. http://publications.edpsciences.org/
ID number or DOI: 10.1051/0004-6361/200911752
Keywords: Crystalline materials; crystalline water ice; eso large program; ice; infrared array camera; Infrared devices; ion irradiation; Kuiper belt; optical-constants; photometry; solar system; Spacecraft observatories; space telescopes; spitzer-space-telescope; surface chemistry; surface-properties; techniques: spectroscopic; trans-Neptunian objects; Transneptunian objects; visible spectroscopy
Subjects: Q Science > QB Astronomy
NAU Depositing Author Academic Status: Faculty/Staff
Department/Unit: College of Engineering, Forestry, and Natural Science > Physics and Astronomy
Date Deposited: 30 Sep 2015 17:05
URI: http://openknowledge.nau.edu/id/eprint/389

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