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Discovery and physical properties of Dactyl, a satellite of asteroid 243 Ida

Abstract

OBSERVATIONS of stellar occultations by asteroids have suggested that some may have satellites1. But given the absence of any confirmatory evidence, the prevailing view has been that although such satellites probably do exist, they are likely to be rare2. Here we report the discovery3 by the Galileo spacecraft of a satellite associated with the asteroid 243 Ida. Although the satellite, Dactyl, is only 1.6km across, it has been imaged with sufficient resolution for geological analysis. We describe the physical properties of Dactyl, with emphasis on its notably smooth shape, its crater population (which includes a crater chain) and its photometric properties. We find that, spectroscopically, Dactyl resembles both Ida and the other members of the Koronis asteroid family, implying a similar composition; small spectral differences may reflect a space weathering process that slightly alters the colours with time. We argue that Dactyl originated during the breakup of the Koronis parent body, and that satellites could be common around other asteroids (particularly members of asteroid families).

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References

  1. Van Flandern, T. C., Tedesco, E. F. & Binzel, R. P. in Asteroids (ed. Gehrels, T.) 443–465 (Univ. Ariz. Press, Tucson, 1979).

    Google Scholar 

  2. Weidenschilling, S. J., Paolicchi, P. & Zappaià, V. in Asteroids II (eds Gehrels, T., Binzel, R. P. & Matthews, M. S.) 643–658 (Univ. Ariz. Press, Tucson, 1989).

    Google Scholar 

  3. Belton, M. J. S. & Carlson, R. IAU Circ. No. 5948 (1994).

  4. Belton, M. J. S. et al. Science 265, 1543–1547 (1994).

    Article  ADS  CAS  Google Scholar 

  5. Simonelli, D. P., Thomas, P. C., Carcich, B. T. & Veverka, J. Icarus 103, 49–61.

  6. Belton, M. J. S. et al. Nature 374, 785–788 (1995).

    Article  ADS  CAS  Google Scholar 

  7. Thomas, P. Icarus 77, 248–274 (1989).

    Article  ADS  Google Scholar 

  8. Gaffey, M. J. et al. Icarus 106, 573–602 (1993).

    Article  ADS  CAS  Google Scholar 

  9. Gradie, J. C., Chapman, C. R. & Williams, J. G. in Asteroids (ed. Gehrels, T.) 359–390 (Univ. Ariz. Press, Tucson, 1979).

    Google Scholar 

  10. Binzel, R. P., Xu, S. & Bus, S. J. Icarus 106, 608–611 (1993).

    Article  ADS  Google Scholar 

  11. Dermott, S. F., Gradie, J. & Murray, C. D. Icarus 62, 289–297 (1985).

    Article  ADS  Google Scholar 

  12. Pieters, C. M., Fischer, E. M., Rode, O. & Basu, A. J. geophys. Res. 98, 20817–20824 (1993).

    Article  ADS  Google Scholar 

  13. Veverka, J. et al. Icarus (submitted).

  14. Sullivan, R. et al. Icarus (submitted).

  15. Gehrels, T., Drummond, J. & Levenson, N. Icarus 70, 257–263 (1987).

    Article  ADS  Google Scholar 

  16. Hartmann, W. K. in Asteroids (ed. Gehrels, T.) 466–479 (Univ. Ariz. Press, Tucson, 1979).

    Google Scholar 

  17. Martelli, G. et al. Astr. Astrophys. 271, 315–318 (1993).

    ADS  Google Scholar 

  18. Durda, D. D. Bull. Am. astr. Soc. 26, 1158 (1994).

    ADS  Google Scholar 

  19. Belton, M. J. S. et al. Science 257, 1647–1652 (1992).

    Article  ADS  CAS  Google Scholar 

  20. Binzel, R. P. Icarus 73, 303–313 (1988).

    Article  ADS  Google Scholar 

  21. Marzari, F., Davis, D. & Vanzani, V. Icarus 113, 168–187 (1995).

    Article  ADS  Google Scholar 

  22. Ostro, S. J. et al. Science 248, 1523–1528 (1990).

    Article  ADS  CAS  Google Scholar 

  23. Bottke, W. F. & Melosh, H. J. Lunar planet. Sci. XXVI, 153–154 (1995).

    ADS  Google Scholar 

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Chapman, C., Veverka, J., Thomas, P. et al. Discovery and physical properties of Dactyl, a satellite of asteroid 243 Ida. Nature 374, 783–785 (1995). https://doi.org/10.1038/374783a0

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