# between absolute magnitude and diameter of the asteroids

The table below provides the relationship between the absolute magnitude (magnitude of a body located at one astronomical unit from the Earth) of an asteroid and its size. The uncertainty on this size depends on the uncertainty on the brightness of the objects and on the value of the albedo. For a bright asteroid (albedo around 0.25), one will read the first value for the size and for a dark asteroid (albedo around 0.05), one will read the second value.
So, for example, an asteroid the absolute magnitude of which being 7 could hace a diameter of 240 kilometers if it is dark and only a diameter of 110 kilometers if it is bright.

Absolute magnitude

Diameter in kilometers        Absolute magnitude   Diameter in meters
2.5 840 - 1900    17.5 810 - 1800
3.0 670 - 1500    18.0 670 - 1500
3.5 530 - 1200    18.5 530 - 1200
4.0 420 - 940    19.0 420 - 940
4.5 330 - 740    19.5 330 - 740
5.0 260 - 590    20.0 260 - 590
5.5 210 - 470    20.5 210 - 470
6.0 170 - 370    21.0 170 - 370
6.5 130 - 300    21.5 130 - 300
7.0 110 - 240    22.0 110 - 240
7.5 85 - 190    22.5 85 - 190
8.0 65 - 150    23.0 65 - 150
8.5 50 - 120    23.5 50 - 120
9.0 40 - 95    24.0 40 - 95
9.5 35 - 75    24.5 35 - 75
10.0 25 - 60    25.0 25 - 60
10.5 20 - 50    25.5 20 - 50
11.0 17 - 37    26.0 17 - 37
11.5 13 - 30    26.5 13 - 30
12.0 11 - 24    27.0 11 - 24
12.5 8 - 19    27.5 8 - 19
13.0 7 - 15    28.0 7 - 15
13.5 5 - 12    28.5 5 - 12
14.0 4 - 9    29.0 4 - 9
14.5 3 - 7    29.5 3 - 7
15.0 3 - 6    30.0 3 - 6
15.5 2 - 5    30.5 2 - 5
16.0 2 - 4    31.0 2 - 4
16.5 1 - 3    31.5 1 - 3
17.0 0.9 - 2    32.0 0.9 - 2