Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years

This article has been updated

Abstract

Comets are composed of dust and frozen gases. The ices are mixed with the refractory material either as an icy conglomerate1, or as an aggregate of pre-solar grains (grains that existed prior to the formation of the Solar System), mantled by an ice layer2,3. The presence of water-ice grains in periodic comets is now well established4,5,6. Modelling of infrared spectra obtained about ten kilometres from the nucleus of comet Hartley 2 suggests that larger dust particles are being physically decoupled from fine-grained water-ice particles that may be aggregates7, which supports the icy-conglomerate model. It is known that comets build up crusts of dust that are subsequently shed as they approach perihelion8,9,10. Micrometre-sized interplanetary dust particles collected in the Earth’s stratosphere and certain micrometeorites are assumed to be of cometary origin11,12,13. Here we report that grains collected from the Jupiter-family comet 67P/Churyumov-Gerasimenko come from a dusty crust that quenches the material outflow activity at the comet surface14. The larger grains (exceeding 50 micrometres across) are fluffy (with porosity over 50 per cent), and many shattered when collected on the target plate, suggesting that they are agglomerates of entities in the size range of interplanetary dust particles. Their surfaces are generally rich in sodium, which explains the high sodium abundance in cometary meteoroids15. The particles collected to date therefore probably represent parent material of interplanetary dust particles. This argues against comet dust being composed of a silicate core mantled by organic refractory material and then by a mixture of water-dominated ices2,3. At its previous recurrence (orbital period 6.5 years), the comet’s dust production doubled when it was between 2.7 and 2.5 astronomical units from the Sun14, indicating that this was when the nucleus shed its mantle. Once the mantle is shed, unprocessed material starts to supply the developing coma, radically changing its dust component, which then also contains icy grains, as detected during encounters with other comets closer to the Sun4,5.

Your institute does not have access to this article

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.

$32.00

All prices are NET prices.

Figure 1: Dust particles.

Change history

  • 11 February 2015

    A minor typo relating to ref. 29 was corrected.

References

  1. Whipple, F. L. A comet model. I. The acceleration of comet Encke. Astrophys. J. 111, 375–394 (1950)

    Article  ADS  Google Scholar 

  2. Greenberg, J. M. Making a comet nucleus. Astron. Astrophys. 330, 375–380 (1998)

    CAS  ADS  Google Scholar 

  3. Greenberg, J. M. & Li, A. Morphological structure and chemical composition of cometary nuclei and dust. Space Sci. Rev. 90, 149–161 (1999)

    CAS  Article  ADS  Google Scholar 

  4. Schulz, R. et al. Detection of water ice grains after the Deep Impact onto comet 9P/Temple 1. Astron. Astrophys. 448, L53–L56 (2006)

    CAS  Article  ADS  Google Scholar 

  5. A'Hearn, M. F. et al. EPOXI at Comet Hartley 2. Science 332, 1396–1400 (2011)

    CAS  Article  ADS  Google Scholar 

  6. Yang, B., Jewitt, D. & Bus, S. J. Comet 17P/Holmes in outburst: the near infrared spectrum. Astron. J. 137, 4538–4546 (2009)

    CAS  Article  ADS  Google Scholar 

  7. Protopapa, S. et al. Water ice and dust in the innermost coma of comet 103P/Hartley 2. Icarus 238, 191–204 (2014)

    CAS  Article  ADS  Google Scholar 

  8. Brin, G. D. & Mendis, D. A. Dust release and mantle development in comets. Astrophys. J. 229, 402–408 (1979)

    CAS  Article  ADS  Google Scholar 

  9. Rickman, H., Fernández, J. A. & Gustafson, B. Å. S. Formation of stable dust mantles on short-period comet nuclei. Astron. Astrophys. 237, 524–535 (1990)

    ADS  Google Scholar 

  10. Jewitt, D. C. From Kuiper belt object to cometary nucleus: the missing ultrared matter. Astron. J. 123, 1039–1049 (2002)

    Article  ADS  Google Scholar 

  11. Brownlee, D. E. in Treatise on Geochemistry (eds Heinrich, D. H. & Karl, K. T. ) 663–685 (Pergamon, 2007)

    Google Scholar 

  12. Nesvorný, D. et al. Cometary origin of the zodiacal cloud and carbonaceous micrometeorites. Implications for hot debris disks. Astrophys. J. 713, 816–836 (2010)

    Article  ADS  Google Scholar 

  13. Dartois, E. et al. Ultracarbonaceous Antarctic micrometeorites, probing the Solar System beyond the nitrogen snow-line. Icarus 224, 243–252 (2013)

    CAS  Article  ADS  Google Scholar 

  14. Guilbert-Lepoutre, A. et al. Pre-perihelion activity of comet 67P/Churyumov-Gerasimenko. Astron. Astrophys. 567, http://dx.doi.org/10.1051/0004-6361/201424186 (2014)

    Article  ADS  Google Scholar 

  15. Trigo-Rodríguez, J. M. & Llorca, J. On the sodium overabundance in cometary meteoroids. Adv. Space Res. 39, 517–525 (2007)

    Article  ADS  Google Scholar 

  16. Schulz, R., Alexander, C., Boehnhardt, H. & Glassmeier, K.-H. Rosetta—ESA’s Mission to the Origin of the Solar System (Springer, 2009)

    Google Scholar 

  17. Schulz, R. Rosetta—one comet rendezvous and two asteroid fly-bys. Sol. Syst. Res. 43, 343–352 (2009)

    Article  ADS  Google Scholar 

  18. Kissel, J. et al. COSIMA—high resolution time-of-flight secondary ion mass spectrometer for the analysis of cometary dust particles onboard ROSETTA. Space Sci. Rev. 128, 823–867 (2007)

    CAS  Article  ADS  Google Scholar 

  19. Hornung, K. et al. Collecting cometary dust particles on metal blacks with the COSIMA instrument onboard ROSETTA. Planet. Space Sci. 103, 309–317 (2014)

    Article  ADS  Google Scholar 

  20. DiSanti, M. A. et al. Temporal evolution of parent volatiles and dust in Comet 9P/Tempel 1 resulting from the Deep Impact experiment. Icarus 187, 240–252 (2007)

    CAS  Article  ADS  Google Scholar 

  21. Villanueva, G. L. et al. The molecular composition of comet C/2007 W1 (Boattini): evidence of a peculiar outgassing and a rich chemistry. Icarus 216, 227–240 (2011)

    CAS  Article  ADS  Google Scholar 

  22. Tozzi, G. P. et al. Sublimating components in the coma of comet C/2000 WM1 (LINEAR). Astron. Astrophys. 424, 325–330 (2004)

    Article  ADS  Google Scholar 

  23. Tsou, P. et al. Stardust encounters comet 81P/Wild 2. J. Geophys. Res. 109, E12S01 (2004)

    ADS  Google Scholar 

  24. Brownlee, D. The Stardust Mission: analyzing samples from the edge of the Solar System. Annu. Rev. Earth Planet. Sci. 42, 179–205 (2014)

    CAS  Article  ADS  Google Scholar 

  25. Kearsley, A. T. et al. Experimental impact features in Stardust aerogel: how track morphology reflects particle structure, composition, and density. Meteorit. Planet. Sci. 47, 737–762 (2012)

    CAS  Article  ADS  Google Scholar 

  26. Krueger, H. et al. COSIMA-Rosetta calibration for in-situ characterization of 67P/Churyumov-Gerasimenko cometary inorganic compounds. Planet. Space Sci. (submitted); preprint at http://arxiv.org/abs/1501.00716 (2015)

  27. Stephan, T. Assessing the elemental composition of comet 81P/Wild 2 by analyzing dust collected by Stardust. Space Sci. Rev. 138, 247–258 (2008)

    CAS  Article  ADS  Google Scholar 

  28. Jessberger, E. K., Christoforidis, A. & Kissel, J. Aspects of the major element composition of Halley’s dust. Nature 332, 691–695 (1988)

    CAS  Article  ADS  Google Scholar 

  29. Lodders, K. Solar System abundances and condensation temperatures of the elements. Astrophys. J. 591, 1220–1247 (2003)

    CAS  Article  ADS  Google Scholar 

  30. Jewitt, D. C. & Meech, K. J. Surface brightness profiles of 10 comets. Astrophys. J. 317, 992–1001 (1987)

    CAS  Article  ADS  Google Scholar 

Download references

Acknowledgements

COSIMA was built by a consortium led by the Max-Planck-Institut für Extraterrestrische Physik, Garching, Germany, in collaboration with the Laboratoire de Physique et Chimie de l’Environnement et de l’Espace, Orléans, France, the Institut d’Astrophysique Spatiale, CNRS/Université Paris Sud, Orsay, France, the Finnish Meteorological Institute, Helsinki, Finland, the Universität Wuppertal, Wuppertal, Germany, von Hoerner und Sulger GmbH, Schwetzingen, Germany, the Universität der Bundeswehr, Neubiberg, Germany, the Institut für Physik, Forschungszentrum Seibersdorf, Seibersdorf, Austria, the Institut für Weltraumforschung, Österreichische Akademie der Wissenschaften, Graz, Austria and is led by the Max-Planck-Institut für Sonnensystemforschung, Göttingen, Germany. The support of the national funding agencies of Germany (DLR, grant 50 QP 1302), France (CNES), Austria, Finland and the ESA Technical Directorate is gratefully acknowledged. S.S. acknowledges the support by the Swedish National Space Board grant (contract number 121/11). We thank the Rosetta Science Ground Segment at the European Space Astronomy Centre, the Rosetta Mission Operations Centre at the European Space Operations Centre, and the Rosetta Project at the European Space Research and Technology Centre for their work, which enabled the science return of the Rosetta mission.

Author information

Authors and Affiliations

Authors

Contributions

M.H. managed the project. J.K., Y.L., J.S., K.H., L.T., J.R., K.V. and R.S. contributed to instrument development. J.R., M.H., H.F., Y.L., J.P., L.T., and O.S. contributed to instrument operations and data distribution. C.B., C.E., D.B., A.B., H.C., N.F., M.G., J.K., K.H., H.L., Y.L., L.L.R., F.-R.O.-D., S.M., J.R., J.S., S.S., L.T., B.Z. and M.H. contributed to instrument and data calibration. Y.L. provided grain images and the porosity value. C.E. provided calibrated mass spectrometry data. R.S. performed comet research and wrote the manuscript. All authors discussed the results and commented on the manuscript.

Corresponding author

Correspondence to Rita Schulz.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Additional information

After the proprietary period of six months the data will be available in the ESA Planetary Science Archive (http://www.rssd.esa.int/index.php?project=PSA).

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Schulz, R., Hilchenbach, M., Langevin, Y. et al. Comet 67P/Churyumov-Gerasimenko sheds dust coat accumulated over the past four years. Nature 518, 216–218 (2015). https://doi.org/10.1038/nature14159

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature14159

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing