List of Notable Asteroids - Largest By Mass

Largest By Mass

Below are the eighteen most-massive measured asteroids. The masses of asteroids are calculated from perturbations caused by Mars and other asteroids. Different sets of astrometric observations lead to different mass determinations; the biggest problem is accounting for all the perturbations of the smaller asteroid.

(All the data above are from Baer et al. 2011, apart from 532 Herculina, which is Kochetova, 2004.)

Significant uncertainties remain. For example, the uncertainty in the estimate of 31 Euphrosyne is enough for its low end to overlap with both 704 Interamnia and 511 Davida, which overlap each other and also with 532 Herculina, which overlaps with 15 Eunomia and 3 Juno. Juno barely overlaps 52 Europa, which in turn overlaps with 16 Psyche. That is, outside the top four, the order of all the asteroids is uncertain. However, none of the lesser asteroids, of which the most massive are thought to be 88 Thisbe (at 17–19×1018 kg), also 7 Iris, 13 Egeria, and 29 Amphitrite (all in the range of ≈16×1018 kg), overlap with Europa or Psyche, so the asteroids in the chart above are likely to be the top dozen unless a hitherto unmeasured asteroid proves to be unexpectedly massive.

The largest asteroid with an accurately measured mass, due to the fact that it has been visited by the probe Dawn, is 4 Vesta at 259.076±0.001×1018 kg. The second-largest asteroid with an accurately measured mass, due to the fact that it has a moon, is 87 Sylvia at 14.78±0.06×1018 kg.

For a more complete list, see List of Solar System objects by size. Other large asteroids such as 48 Doris and 423 Diotima currently only have assumed masses.