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Water ice and organics on the surface of the asteroid 24 Themis

Abstract

It has been suggested1,2,3 that Earth’s current supply of water was delivered by asteroids, some time after the collision that produced the Moon (which would have vaporized any of the pre-existing water). So far, no measurements of water ice on asteroids4,5 have been made, but its presence has been inferred from the comet-like activity of several small asteroids, including two members of the Themis dynamical family6. Here we report infrared spectra of the asteroid 24 Themis which show that ice and organic compounds are not only present on its surface but also prevalent. Infrared spectral differences between it and other asteroids make 24 Themis unique so far, and our identification of ice and organics agrees with independent results7 that rule out other compounds as possible sources of the observed spectral structure. The widespread presence of surface ice on 24 Themis is somewhat unexpected because of the relatively short lifetime of exposed ice at this distance (3.2 au) from the Sun. Nevertheless, there are several plausible sources, such as a subsurface reservoir that brings water to the surface through ‘impact gardening’ and/or sublimation.

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Figure 1: Rotationally resolved near-infrared reflectance spectra of 24 Themis.

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References

  1. Mottl, M. J., Glazer, B. T., Kaise, R. I. & Meech, K. J. Water and astrobiology. Chem. Erde Geochem. 67, 253–282 (2008)

    Article  ADS  Google Scholar 

  2. Drake, M. J. & Campins, H. in Asteroids, Comets and Meteorites (eds Lazzaro, D., Ferraz-Mello, S. & Fernández, J. A.) 381–394 (Cambridge Univ. Press, 2006)

    Google Scholar 

  3. Morbidelli, A. et al. Source regions and time scales for the delivery of water to Earth. Meteorit. Planet. Sci. 35, 1309–1320 (2000)

    Article  ADS  CAS  Google Scholar 

  4. Rivkin, A. S. & Emery, J. P. in Asteroids, Comets, Meteors 2008 abstr. 8099 (Lunar Planet. Inst., 2008)

    Google Scholar 

  5. Milliken, R. & Rivkin, A. Brucite and carbonate assemblages from altered olivine-rich materials on Ceres. Nature Geosci. 2, 258–261 (2009)

    Article  ADS  CAS  Google Scholar 

  6. Hsieh, H. H. & Jewitt, D. A population of comets in the main asteroid belt. Science 312, 561–563 (2006)

    Article  ADS  CAS  Google Scholar 

  7. Rivkin, A. S. & Emery, J. P. Detection of ice and organics on an asteroidal surface. Nature 10.1038/nature09028 (this issue)

  8. Nesvorný, D. et al. Origin of the near-ecliptic circumsolar dust band. Astrophys. J. 679, L143–L146 (2008)

    Article  ADS  Google Scholar 

  9. Licandro, J. et al. The nature of active asteroids in the main belt. Bull. Am. Astron. Soc. 39, 470 (2007)

    Google Scholar 

  10. Schorghofer, N. The lifetime of ice on main belt asteroids. Astrophys. J. 682, 697–705 (2008)

    Article  ADS  Google Scholar 

  11. Rivkin, A. S., Howell, E. S., Vilas, F. & Lebofsky, L. A. in Asteroids III (eds Bottke, W. F., Cellino, A., Paolicchi, P. & Binzel, R. P.) 235–253 (Univ. Arizona Press, 2002)

    Google Scholar 

  12. Pieters, C. M. & Hiroi, T. in Lunar Planet. Sci. XXXV (ed. Mackwell, S. J.) abstr. 1720 (Lunar Planet. Inst., 2004)

    Google Scholar 

  13. Clark, R. N. et al. USGS digital spectral library splib06a (Digital Data Ser. 231, US Geol. Survey, 2007)

  14. Baldridge, A. M., Hook, S. J., Grove, C. I. & Rivera, G. The ASTER spectral library version 2.0. Remote Sens. Environ. 113, 711–715 (2009)

    Article  ADS  Google Scholar 

  15. Blanco, C. & Riccioli, D. Pole coordinates and shape of 30 asteroids. Astron. Astrophys. Suppl. Ser. 131, 385–394 (1998)

    Article  ADS  Google Scholar 

  16. Lebofsky, L. Stability of frosts in the solar system. Icarus 25, 205–217 (1975)

    Article  ADS  CAS  Google Scholar 

  17. Sunshine, J. et al. Exposed water ice deposits on the surface of comet 9P/Tempel 1. Science 311, 1453–1455 (2006)

    Article  ADS  CAS  Google Scholar 

  18. Thomas, P. C. et al. Differentiation of the asteroid Ceres as revealed by its shape. Nature 437, 224–226 (2005)

    Article  ADS  CAS  Google Scholar 

  19. McKinnon, W. B., Prialnik, D., Stern, S. A. & Coradini, A. in The Solar System Beyond Neptune (eds Barucci, M. A., Boehnhardt, H., Cruikshank, D. P. & Morbidelli, A.) 213–241 (Univ. Arizona Press, 2008)

    Google Scholar 

  20. Pinilla-Alonso, N. et al. The surface of (136108) Haumea (2003 EL61), the largest carbon-depleted object in the trans-Neptunian belt. Astron. Astrophys. 496, 547–556 (2009)

    Article  ADS  CAS  Google Scholar 

  21. Heiken, G. H., Vaniman, D. T. & French, B. M. Lunar Sourcebook: A User’s Guide to the Moon 736 (Cambridge Univ. Press, 1991)

    Google Scholar 

  22. Khare, B. N. et al. Production and optical constraints of ice tholin from charged particle irradiation of (1:6) C2H6/H2O at 77 K. Icarus 103, 290–300 (1993)

    Article  ADS  CAS  Google Scholar 

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Acknowledgements

H.C. and K.H. are visiting astronomers at the Infrared Telescope Facility (IRTF), which is operated by the University of Hawaii under cooperative agreement no. NCC 5-538 with NASA. All the observations used in this publication were obtained at the IRTF. H.C. acknowledges support from NASA’s Planetary Astronomy programme and from the US National Science Foundation. H.C. was a visiting Fulbright Scholar at the “Instituto de Astrofísica de Canarias” in Tenerife, Spain, and a visiting astronomer at Observatoire de la Côte d’Azur, Nice, France. J.L. acknowledges support from the Spanish ‘Ministerio de Ciencia e Innovación’. T.M.-D. was supported by the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico and by the Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro. We benefited from discussions with D. Cruikshank, M. Delbó, P. Michel, A. Morbidelli and T. Roush.

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Authors and Affiliations

Authors

Contributions

H.C. and K.H. carried out the observations, the data reduction and the interpretation of the results. N.P.-A. carried out the spectral modelling and interpretation. E.S.H. provided software and participated extensively in the data reduction. M.S.K. and Y.F. provided software and participated extensively in the thermal modelling of the asteroid. T.M.-D. carried out the spectral comparison with meteorites and mineral samples. J.L. and J.Z. contributed to the interpretation of the spectroscopic results. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Humberto Campins.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Information comprising: Observations and Data Reduction; Spectral Modelling; Supplementary Table 1; Supplementary References and Supplementary Figures S1-S2 with legends. (PDF 219 kb)

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Campins, H., Hargrove, K., Pinilla-Alonso, N. et al. Water ice and organics on the surface of the asteroid 24 Themis. Nature 464, 1320–1321 (2010). https://doi.org/10.1038/nature09029

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