This shows albedo vs. distance for asteroids with measured albedos: 2,557 asteroids are shown, mostly with IRAS-measured albedos. Note the lower albedos for asteroids beyond 3.3 AU, including Jupiter Trojans at 5.2 AU.
This graph shows the trend in asteroid albedo vs. distance by averaging albedos for the sample from the previous graph (averaged by bins in distance with 37 per bin).
This graph depicts osculating orbital elements for asteroids, with the color of points indicating albedo. Note again the general trend of decreasing albedo with increasing semimajor axis. (Osculating elements are elements at a given point in time, here 22 August 2008; these elements change over time due to gravitational perturbations by the planets.) The boxed region is represented in the next figure (using proper elements instead).
This graph is similar to the previous graph, but depicts proper elements and shows a smaller range of a and e, for 1,757 asteroids. Some clustering is evident here, representing asteroid families (groups of asteroids that may be fragments of a common progenitor). One example is the group of bright asteroids with a=~2.2 AU, e=~0.15, which includes members of asteroid family 187. (Proper elements are orbital elements averaged over time.)
Sources: asteroid albedos from NASA PDS databases (Tedesco, E.F., P.V. Noah, M. Noah, and S.D. Price. IRAS Minor Planet Survey. IRAS-A-FPA-3-RDR-IMPS-V6.0. NASA Planetary Data System, 2004; Morrison, D. and Zellner, B., TRIAD Radiometric Diameters and Albedos V1.0. EAR-A-COMPIL-5-TRIADRAD-V1.0. NASA Planetary Data System, 2007; Shevchenko, V.G. and Tedesco, E.F., Asteroid Albedos from Stellar Occultations V1.0. EAR-A-VARGBDET-5-OCCALB-V1.0. NASA Planetary Data System, 2007; Tedesco, E.T., M.P. Egan, and S.D. Price. MSX Infrared Minor Planet Survey. MSX-A-SPIRIT3-5-SBN0003-MIMPS-V1.0. NASA Planetary Data System, 2004; Davis, D.R. and Neese, C., Eds., Asteroid Albedos. EAR-A-5-DDR-ALBEDOS-V1.1. NASA Planetary Data System, 2002). Osculating elements from Ted Bowell, Asteroid Orbital Elements Database, Lowell Observatory, 2008, and proper elements from Andrea Milani, Asteroid Proper Elements, NASA PDS, 1998.
© 2003, 2008 by Wm. Robert Johnston.
Last modified 4 August 2008.
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