2009/12/31 by H. A. Weaver, P. D. Feldman, W. J. Merline +15 · 21 citations
Environmental Science · Physics and Astronomy · #Absolute magnitude #Albedo (alchemy) #Asteroid #Astro and Planetary Science #Astronomy #Astrophysics #Galaxy #Geometric albedo #Isotope Analysis in Ecology #Optics #Photometry (optics) #Physics #Planetary Science and Exploration #Wavelength #astro-ph.EP
paper · pdf · doi:10.1051/0004-6361/200913950
published in Astronomy and Astrophysics 518, A4 (EDP Sciences) · 14 pages, 2 tables, 8 figures
openalex publication_date 2010/07/01 · arxiv created 2010/07/06 · arxiv updated 2015/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
<i>Context. <i/>The asteroid (21) Lutetia is the target of a planned close encounter by the <i>Rosetta<i/> spacecraft in July 2010. To prepare for that flyby, Lutetia has been extensively observed by a variety of astronomical facilities.<i>Aims. <i/>We used the <i>Hubble Space Telescope (HST)<i/> to determine the albedo of Lutetia over a wide wavelength range, extending from ~1500 Å to ~7000 Å.<i>Methods. <i/>Using data from a variety of <i>HST<i/> filters and a ground-based visible light spectrum, we employed synthetic photometry techniques to derive absolute fluxes for Lutetia. New results from ground-based measurements of Lutetia's size and shape were used to convert the absolute fluxes into albedos.<i>Results. <i/>We present our best model for the spectral energy distribution of Lutetia over the wavelength range 1200-8000 Å. There appears to be a steep drop in the albedo (by a factor of ~2) for wavelengths shorter than ~3000 Å. Nevertheless, the far ultraviolet albedo of Lutetia (~10%) is considerably larger than that of typical C-chondrite material (~4%). The geometric albedo at 5500 Å is 16.5 <i>±<i/> 1%. <i>Conclusions. <i/>Lutetia's reflectivity is not consistent with a metal-dominated surface at infrared or radar wavelengths, and its albedo at all wavelengths (UV-visibile-IR-radar) is larger than observed for typical primitive, chondritic material. We derive a relatively high FUV albedo of ~10%, a result that will be tested by observations with the <i>Alice<i/> spectrograph during the <i>Rosetta<i/> flyby of Lutetia in July 2010.