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Astron. Astrophys. 358, 1133-1141 (2000)

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ISO results on bright Main Belt asteroids: PHT-S observations *

E. Dotto 1,2, T.G. Müller 3, M.A. Barucci 1, Th. Encrenaz 1, R.F. Knacke 4, E. Lellouch 1, A. Doressoundiram 1, J. Crovisier 5, J.R. Brucato 6, L. Colangeli 6 and V. Mennella 6

1 DESPA - Observatoire de Paris, 92195 Meudon, France
2 Osservatorio Astronomico di Torino, Italy
3 ISO Data Centre, ESA Astrophysics Division, Villafranca, Spain
4 Penn. State University, Erie, PA, USA
5 ARPEGES - Observatoire de Paris, 92195 Meudon, France
6 Osservatorio Astronomico di Capodimonte, Italy

Received 22 June 1999 / Accepted 27 March 2000


Observations of asteroids have been performed by the ISO satellite with PHT-S. The aim of these observations was to investigate the physical and compositional properties of five bright Main Belt Asteroids (1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, and 52 Europa) in the spectral range 5.8-11.6 µm. The Standard Thermal Model and a black-body fit have been applied to the obtained spectra to derive sub-solar and black-body temperatures. An advanced Thermo-Physical Model has been applied to model the thermal continuum. In order to better interpret the observed spectral features, we compared the ISO data with meteorite and mineral spectra available in literature and with spectra of a selected number of minerals obtained in laboratory. The spectral behaviour of all the observed asteroids from 8 to 11 µm suggest the presence of silicates on the surfaces.

Key words: techniques: spectroscopic – minor planets, asteroids – infrared: solar system – ISO – Asteroid Individual: 1 Ceres, 2 Pallas, 3 Juno, 4 Vesta, 52 Europa

* Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries: France, Germany, the Netherlands and the United Kingdom) with the participation of ISAS and NASA.

Send offprint requests to: E. Dotto, Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese (TO), Italy (dotto@to.astro.it)

© European Southern Observatory (ESO) 2000

Online publication: June 20, 2000