Surface properties of Rosetta's targets (21) Lutetia and (2867) Steins from ESO observations

Carvano, J.M. and Barucci, M.A. and Delbo, M. and Fornasier, S. and Lowry, S. and Fitzsimmons, A. (2008) Surface properties of Rosetta's targets (21) Lutetia and (2867) Steins from ESO observations. Astronomy and Astrophysics, 479 (1). pp. 241-248. ISSN 0004-6361. E-ISSN 1432-0746. (doi: (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Aims. The aim of this work is to constrain the size, composition and surface properties of asteroids (2867) Steins and (21) Lutetia, targets of the Rosetta mission. Rosetta is en route to rendezvous with comet 67P/Churyumov-Gerasimenko. Methods.Thermal-Infrared N-band observations for Lutetia and Steins were obtained using, respectively, TIMMI2 on the ESO 3.6-m telescope at La Silla and VISIR at the UT3 VLT telescope on Cerro Paranal; visible light curves for Steins were obtained using NTT+SUSI2, while -band photometry for Lutetia was obtained with the 2.0-m Faulkes Telescope North on Haleakala. For Steins, the NEATM model was used to constrain its visible geometric albedo and beaming parameter. A detailed thermophysical model was implemented and used to analyze our set of observations of Lutetia as well as previous reported measurements.Results. The visible photometry of Steins was used along with data from the literature to yield a slope parameter of. Problems during the observations led to the loss of measurements on two of the three -band filters requested for Steins. Using the remaining data and the polarimetric albedo recently published, we were able to constrain the thermal beaming parameter as 1.2$, which is more similar to near-Earth asteroids and suggests either high thermal inertia or a very rough surface. For Lutetia, the best fit visible geometric albedo obtained with our model and the reported observation is , significantly lower than that obtained if one applies the same model to previously reported measurements. The discrepancy cannot be explained solely by assuming inhomogeneities in the surface properties and we suggest that the most plausible explanation is the presence of one or more large craters on the northern hemisphere. For both sets of measurements, the implied single scattering albedo of Lutetia is compatible with laboratory measurements of carbonaceous chondrite meteorites. © 2008 ESO.

Item Type: Article
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Astron. Astrophys. [Field not mapped to EPrints] AD - Observatório Nacional (COAA), Rua Gal. José Cristino 77, Sao Cristovao, CEP20921-400 Rio de Janeiro RJ, Brazil [Field not mapped to EPrints] AD - LESIA, Observatoire de Paris, 5 Place Jules Janssen, 92195 Meudon Principal Cedex, France [Field not mapped to EPrints] AD - Laboratoire Cassiopée, Observatoire de la Cote d'Azur, BP 4229, 06304 Nice Cedex 04, France [Field not mapped to EPrints] AD - Université de Paris 7, Denis Diderot, France [Field not mapped to EPrints] AD - Astrophysics Research Centre, Physics Building, Queen's University Belfast, Belfast BT7 1NN, United Kingdom [Field not mapped to EPrints] AD - NASA Jet Propulsion Laboratory (MS 183-301), 4800 Oak Grove Drive, Pasadena, CA 91109, United States [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Infrared: solar system, Minor planets, asteroids, Asteroids, Earth (planet), Infrared radiation, Mathematical models, Photometry, Telescopes, Minor planets, Thermal beaming, Surface properties
Subjects: Q Science > QB Astronomy
Divisions: Faculties > Sciences > School of Physical Sciences > Centre for Astrophysics and Planetary Sciences
Depositing User: Stephen Lowry
Date Deposited: 08 Dec 2015 23:01 UTC
Last Modified: 21 Dec 2015 09:27 UTC
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