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MIDI observations of 1459 Magnya: First attempt of interferometric observations of asteroids with the VLTI |
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| Authors: | Marco Delbo Mario Gai Sebastiano Ligori Laura Saba Davide Gandolfi Carlo Blanco Markus Wittkowski |
| Institution: | a INAF-Osservatorio Astronomico di Torino, Strada Osservatorio 20, 10025 Pino Torinese (TO), Italy b Dipartimento di Fisica e Astronomia, Università degli studi di Catania, Via S. Sofia 78, 95123 Catania, Italy c Department of Physics, University of Lecce, Via per Arnesano, 73100 Lecce, Italy d European Southern Observatory, Karl-Schwarzschild-Straße, 2 D-85748 Garching bei München, Germany |
| Abstract: | The Very Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO) can be used to obtain direct determination of the sizes and the albedos of asteroids. We present results of the first attempt to carry out interferometric observations of asteroids with the Mid Infrared Interferometric Instrument (MIDI) at the VLTI. Our target was 1459 Magnya. This is the only V-type asteroid known to exist in the outer main-belt, and its IRAS-albedo turns out to be rather low for an object of this taxonomic class. Interferometric fringes were not detected, very likely due to the fact that the flux emitted by the asteroid was lower than expected and below the MIDI threshold for fringe detection. However, by fitting the Standard Thermal Model to the N-band infrared flux measured by MIDI in photometric mode and to the visible absolute magnitude, obtained from quasi-simultaneous B- and V-band photometric observations, we have derived a geometric visible albedo of 0.37±0.06 and an effective diameter of 17±1 km. This new estimate of the albedo differs from that previously obtained by IRAS and is more consistent with the V-type taxonomic classification of 1459 Magnya. |
| Keywords: | Asteroids Infrared observations Photometry Instrumentation |
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