Movatterモバイル変換

[0]ホーム
URL:

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.

Advertisement

Nature
  • Letter
  • Published:

A low density of 0.8 g cm-3 for the Trojan binary asteroid 617 Patroclus

Naturevolume 439, pages565–567 (2006)Cite this article

Abstract

The Trojan population consists of two swarms of asteroids following the same orbit as Jupiter and located at the L4 and L5 stable Lagrange points of the Jupiter–Sun system (leading and following Jupiter by 60°). The asteroid 617 Patroclus is the only known binary Trojan1. The orbit of this double system was hitherto unknown. Here we report that the components, separated by 680 km, move around the system's centre of mass, describing a roughly circular orbit. Using this orbital information, combined with thermal measurements to estimate the size of the components, we derive a very low density of. The components of 617 Patroclus are therefore very porous or composed mostly of water ice, suggesting that they could have been formed in the outer part of the Solar System2.

This is a preview of subscription content,access via your institution

Access options

Access through your institution

Subscription info for Japanese customers

We have a dedicated website for our Japanese customers. Please go tonatureasia.com to subscribe to this journal.

Buy this article

  • Purchase on SpringerLink
  • Instant access to full article PDF

Prices may be subject to local taxes which are calculated during checkout

Figure 1:617 Patroclus observed with the Keck 10-m telescope on the Mauna Kea summit in Hawaii and its adaptive optics system.
Figure 2:Several good-fit orbits of the 617 Patroclus components estimated using 2004–2005 Keck LGS adaptive optics data.
Figure 3:Relationship between the sample density and the porosity of 617 Patroclus for various compositions.

Similar content being viewed by others

References

  1. Merline, W. J. et al. S/2001 (617) 1.IAU Circ.7741 (2001)

  2. Morbidelli, A., Levison, H. F., Tsiganis, K. & Gomes, R. Chaotic capture of Jupiter's Trojan asteroids in the early Solar System.Nature435, 462–465 (2005)

    Article ADS CAS  Google Scholar 

  3. Chapman, C. R. et al. Discovery and physical properties of Dactyl, a satellite of asteroid 243 Ida.Nature374, 783–785 (1995)

    Article ADS CAS  Google Scholar 

  4. Merline, W. J. L., et al. inAsteroids III (eds Bottke, W. F., Cellino, A., Paolicchi, P. & Binzel, R. P.) 289–312 (Univ. Arizona Press, Tucson, 2002)

    Google Scholar 

  5. Pravec, P. et al. Photometric survey of binary near-Earth asteroids.Am. Astron. Soc. Div. Planet. Sci.36, abstr. 28.04 (2004)

  6. Marchis, F., Descamps, P., Hestroffer, D. & Berthier, J. Discovery of the triple asteroidal system 87 Sylvia.Nature436, 822–824 (2005)

    Article ADS CAS  Google Scholar 

  7. Roth, K. C. et al. Hokupa'a performance and point spread function characterization.Bull. Am. Astron. Soc.33, abstr. 02.02, 785 (2001)

    ADS  Google Scholar 

  8. Berthier, J. & Marchis, F. A tool for observations of Centaurs/Kuiper Objects with adaptive optics systems.Bull. Am. Astron. Soc.33, abstr. 12.17, 1049 (2001)

    ADS  Google Scholar 

  9. Marchis, F. et al. inAdvancements in Adaptive Optics (eds Bonaccini, D., Ellerbroek, B. L. & Ragazzoni, R.)Proc. SPIE5490, 338–350 (2004).

  10. Bouchez, A. H. et al. inAdvancements in Adaptive Optics (eds Bonaccini, D., Ellerbroek, B. L. & Ragazzoni, R.)Proc. SPIE5490, 321–330 (2004).

  11. Hestroffer, D. & Vachier, F. Orbit determination of binary asteroids.IAU Symp. 229 on Asteroids, Comets and Meteors (Buzios, Rio de Janeiro, Brazil, 2005) abstr. 10.9, 87 (IAU, 2005)

    Google Scholar 

  12. Descamps, P. Orbit of an astrometric binary system.Celest. Mech. Dynam. Astron.92, 381–402 (2005)

    Article ADS MathSciNet  Google Scholar 

  13. Marchis, F., et al. On the diversity of binary asteroid orbits.IAU Symp. 229 on Asteroids, Comets and Meteors (Buzios, Rio de Janeiro, Brazil, 2005) abstr. 10.1, 83 (IAU, 2005)

    Google Scholar 

  14. Marchis, F. et al. Mass and density of asteroid 121 Hermione from an analysis of its companion orbit.Icarus (in the press)

  15. Veillet, C. et al. The binary Kuiper-belt 1998 WW31.Nature416, 711–713 (2000)

    Article ADS  Google Scholar 

  16. Fernandez, Y. et al. The albedo distribution of jovian trojan asteroids.Astron. J.126, 1563–1574 (2003)

    Article ADS  Google Scholar 

  17. Emery, J. P., Cruikshank, D. P. & Van Cleve, J. Thermal emission spectroscopy of asteroids with the Spitzer Space Telescope.Am. Astron. Soc. Div. Planet. Sci.37, abstr. 15.07 (2005)

  18. Merline, W. J. L. et al. Discovery of a moon orbiting the asteroid 45 Eugenia.Nature401, 565–569 (1999)

    Article ADS CAS  Google Scholar 

  19. Marchis, F., Descamps, P., Berthier, J., Hestroffer, D. & de Pater, I. Fine analysis of 121 Hermione, 45 Eugenia, and 90 Antiope binary asteroid systems with AO observations.Am. Astron. Soc. Div. Planet. Sci.36, abstr. 46.02 (2004)

  20. Descamps, P., et al. Insights on 90 Antiope double asteroid combining VLT-AO and lightcurve observations.IAU Symp. 229 on Asteroids, Comets and Meteors (Buzios, Rio de Janeiro, Brazil, 2005) abstr. 10.7, 87 (IAU, 2005)

    Google Scholar 

  21. Anderson, J. D. et al. Amalthea's density is less than that of water.Science308 (5726), 1291–1293 (2005)

    Article ADS CAS  Google Scholar 

  22. Britt, D. T., Yeomans, D., Housen, K. & Consolmagno, G. inAsteroids III (eds Bottke, W. F., Cellino, A., Paolicchi, P. & Binzel, R. P.) 485–500 (Univ. Arizona Press, Tucson, 2002)

    Google Scholar 

  23. Gladman, B., Quinn, D., Nicholson, P. & Rand, R. Synchronous locking of tidally evolving satellites.Icarus122, 166–172 (1996)

    Article ADS  Google Scholar 

  24. Angeli, C. A. et al. A contribution to the study of asteroids with long rotation period.Planet. Space Sci.47, 699–714 (1999)

    Article ADS CAS  Google Scholar 

  25. Michalowski, T. et al. Eclipsing binary asteroid 90 Antiope.Astron. Astrophys.423, 1159–1168 (2004)

    Article ADS  Google Scholar 

  26. Tohline, J. E. The origin of binary stars.Annu. Rev. Astron. Astrophys.40, 349–385 (2002)

    Article ADS  Google Scholar 

  27. Weidenshilling, S. J., Marzari, F., Davis, D. R. & Neese, C. Origin of the double asteroid 90 Antiope: a continuing puzzle.Lunar Planet. Sci.XXXII, 1890 (2001)

    ADS  Google Scholar 

  28. Goldreich, P., Lithwick, Y. & Re'em, S. Formation of Kuiper-belt binaries by dynamical friction and three-body encounters.Nature410, 643–646 (2002)

    Article ADS  Google Scholar 

  29. Astakhov, S. A., Lee, E. A. & Farrelly, D. Formation of Kuiper-belt binaries through multiple chaotic scattering encounters with low-mass intruders.Mon. Not. R. Astron. Soc.360, 401–415 (2005)

    Article ADS  Google Scholar 

  30. Walsh, K. J. & Richardson, D. C. Binary near-Earth asteroid formation: rubble pile model of tidal disruptions.Am. Astron. Soc. Div. Planet. Sci.37, abstr. 14.11 (2005)

Download references

Acknowledgements

This work was supported by the National Science Foundation Science and Technology Center for Adaptive Optics and by the National Aeronautics and Space Administration (NASA) issue through the Science Mission Directorate Research and Analysis programmes. Most of the data were obtained at the W. M. Keck observatory, which is operated as a scientific partnership between the California Institute of Technology, the University of California and NASA. Additional observations were obtained at the Gemini Observatory (acquired through the Gemini Science Archive). Author Contributions F.M. and the IMCCE researchers processed, analysed and interpreted the data. The 2004–2005 campaign of observations with Keck LGS adaptive optics was conducted by the team from the W. M. Keck Observatory, and other University of California at Berkeley researchers.

Author information

Authors and Affiliations

  1. Department of Astronomy, University of California, 601 Campbell Hall, California, 94720, Berkeley, USA

    Franck Marchis, Imke de Pater & Michael H. Wong

  2. Institut de Mécanique Céleste et de Calculs des Éphémérides, UMR CNRS 8028, Observatoire de Paris, 77 Avenue Denfert-Rochereau, F-75014, Paris, France

    Daniel Hestroffer, Pascal Descamps, Jérôme Berthier & Frédéric Vachier

  3. W. M. Keck Observatory, 65-1120 Mamalahoa Highway, Hawaii, 96743, Kamuela, USA

    Antonin H. Bouchez, Randall D. Campbell, Jason C. Y. Chin, Marcos A. van Dam, Scott K. Hartman, Erik M. Johansson, Robert E. Lafon, David Le Mignant, Paul J. Stomski, Doug M. Summers & Peter L. Wizinovich

Authors
  1. Franck Marchis
  2. Daniel Hestroffer
  3. Pascal Descamps
  4. Jérôme Berthier
  5. Antonin H. Bouchez
  6. Randall D. Campbell
  7. Jason C. Y. Chin
  8. Marcos A. van Dam
  9. Scott K. Hartman
  10. Erik M. Johansson
  11. Robert E. Lafon
  12. David Le Mignant
  13. Imke de Pater
  14. Paul J. Stomski
  15. Doug M. Summers
  16. Frédéric Vachier
  17. Peter L. Wizinovich
  18. Michael H. Wong

Corresponding author

Correspondence toFranck Marchis.

Ethics declarations

Competing interests

Reprints and permissions information is available atnpg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Supplementary information

Supplementary Table 1

This Supplementary Table summarizes the measurements performed on each observation for the analysis, such as the relative positions of the components (X, Y based on a fit by a gaussian function in arcsec), the difference of brightness in magnitude, and the residual mean square fitting error of our model. (XLS 18 kb)

Rights and permissions

About this article

Cite this article

Marchis, F., Hestroffer, D., Descamps, P.et al. A low density of 0.8 g cm-3 for the Trojan binary asteroid 617 Patroclus.Nature439, 565–567 (2006). https://doi.org/10.1038/nature04350

Download citation

This article is cited by

Access through your institution
Buy or subscribe

Advertisement

Search

Advanced search

Quick links

Nature Briefing

Sign up for theNature 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
[8]ページ先頭
©2009-2025 Movatter.jp