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An abundant population of small irregular satellites around Jupiter

Naturevolume 423pages261263 (2003) | Download Citation



Irregular satellites have eccentric orbits that can be highly inclined or even retrograde relative to the equatorial planes of their planets. These objects cannot have formed by circumplanetary accretion, unlike the regular satellites that follow uninclined, nearly circular and prograde orbits1. Rather, they are probably products of early capture from heliocentric orbits2,3,4,5. Although the capture mechanism remains uncertain, the study of irregular satellites provides a window on processes operating in the young Solar System. Families of irregular satellites recently have been discovered around Saturn (thirteen members, refs 6, 7), Uranus (six, ref. 8) and Neptune (three, ref. 9). Because Jupiter is closer than the other giant planets, searches for smaller and fainter irregular satellites can be made. Here we report the discovery of 23 new irregular satellites of Jupiter, so increasing the total known population to 32. There are five distinct satellite groups, each dominated by one relatively large body. The groups were most probably produced by collisional shattering of precursor objects after capture by Jupiter.

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We thank Y. Fernandez for help with the observations. The Canada–France–Hawaii telescope is operated by the National Research Council of Canada, Le Centre National de la Recherche Scientifique de France, and the University of Hawaii. This work was supported by a grant to D.C.J. from NASA.

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  1. Institute for Astronomy, University of Hawaii, 2680 Woodlawn Drive, Honolulu, Hawaii, 96822, USA

    • Scott S. Sheppard
    •  & David C. Jewitt


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The authors declare that they have no competing financial interests.

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Correspondence to Scott S. Sheppard.

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