Asteroid albedos: graphs of data

by Wm. Robert Johnston
last updated 19 March 2017

The following figures show asteroid albedos as a function of orbital parameters, based on a compilation of 139,900 reported measurements of asteroid/TNO albedos. Most of these measurements are from WISE. A breakdown and list of sources is provided at the end of the page.

This shows albedo vs. distance for asteroids with measured albedos: 139,727 asteroids are shown, mostly with WISE-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 as statistics for the sample from the previous graph (binned in distance with 100-1000 per bin). The blue line shows median albedo, the red and green lines span 95% of the binned samples.


This shows asteroid eccentricities vs. semimajor axis with colors indicating albedo ranges. These and remaining plots are limited to the 5,957 asteroids with measured diameters of 13 km or more, and use osculating elements.


Same as previous plot, but a closer view of the main belt.


This shows asteroid inclination vs. semimajor axis with colors indicating albedo ranges.


Same as previous plot, but a closer view of the main belt.


The following table summarizes the sources for albedo values used in the above figures, as of 2014 ("object count, adopted figures") and the total number of objects with albedo measurements available from each source (the latter values overlap amongst sources).

method/sourceobject count, adopted figurespercenttotal objects observed (figures overlap)
thermal/WISE 137,616 98.37 139,465
thermal/Akari 1,633 1.17 5,112
thermal/IRAS 158 0.11 2,470
thermal/Spitzer, MSX, others 264 0.19 826
radar/ground-based 44 0.03 117
direct imaging/HST, spacecraft, adaptive optics 12 0.01 101
occultation timing/ground-based 0 0.00 56
TNOs and Centaurs, all methods 173 0.12 173


The following table provides updated figures as of March 2017 (this includes data not yet represented in the figures above).

method/sourceobject count, adopted figurespercenttotal objects observed (figures overlap)
thermal/WISE 138,892 97.14 140,398
thermal/Spitzer 1,980 1.39 2,921
thermal/Akari 1,632 1.14 5,115
thermal/IRAS 159 0.11 2,471
radar/ground-based 138 0.10 309
thermal/other 75 0.05 139
thermal/Herschel 70 0.05 86
dynamic (TNOs/Centaurs) 21 0.01 35
direct imaging/HST, spacecraft 12 0.01 26
occultation timing/ground-based 7 0.00 56
direct imaging/ground-based adaptive optics 1 0.00 79
TOTAL 142,987100.00 N/A

Fraction of known asteroids and TNOs with measured diameters (as of March 2017):

numbered objectsunnumbered objectstotal objectspercent numbered
with diameter measurement 126,725 16,262 142,987 87.36
without diameter measurement 361,724 225,613 587,337 59.97
total 488,449 241,875 730,324 65.46
percent with diameter measurement 25.94 6.72 19.58 100.00


Sources:


© 2003-2016, 2017 by Wm. Robert Johnston.
Last modified 19 March 2017.
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