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.

  • Letter
  • Published:

Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits

Abstract

The Kuiper belt1 extends from the orbit of Neptune at 30 au to an abrupt outer edge about 50 au from the Sun2. Beyond the edge is a sparse population of objects with large orbital eccentricities3,4. Neptune shapes the dynamics of most Kuiper belt objects, but the recently discovered planet 2003 VB12 (Sedna5) has an eccentric orbit with a perihelion distance of 70 au, far beyond Neptune's gravitational influence6,7,8. Although influences from passing stars could have created the Kuiper belt's outer edge and could have scattered objects into large, eccentric orbits9,10, no model currently explains the properties of Sedna. Here we show that a passing star probably scattered Sedna from the Kuiper belt into its observed orbit. The likelihood that a planet at 60–80 au can be scattered into Sedna's orbit is about 50 per cent; this estimate depends critically on the geometry of the fly-by. Even more interesting is the 10 per cent chance that Sedna was captured from the outer disk of the passing star. Most captures have very high inclination orbits; detection of such objects would confirm the presence of extrasolar planets in our own Solar System.

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

Access options

Buy this article

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

Figure 1: Stirring of the eccentricities of planets by the close pass of a Sun-like star.
Figure 2: Orbital elements of planets, formed in situ in the planetary disk, after the fly-by of a one-solar-mass star as a function of final heliocentric distance.
Figure 3: Orbital elements of planets, initially in a ‘scattered disk’, after a fly-by, as described in Fig. 2.

Similar content being viewed by others

References

  1. Luu, J. X. & Jewitt, D. C. Kuiper belt objects: Relics from the accretion disk of the Sun. Annu. Rev. Astron. Astrophys. 40, 63–101 (2002)

    Article  ADS  Google Scholar 

  2. Allen, R. L., Bernstein, G. M. & Malhotra, R. The edge of the solar system. Astrophys. J. 549, L241–L244 (2001)

    Article  ADS  Google Scholar 

  3. Trujillo, C., Jewitt, D. & Luu, J. Population of the scattered Kuiper belt. Astrophys. J. 102, 529–533 (2002)

    Google Scholar 

  4. Gladman, B. et al. The structure of the Kuiper belt: Size distribution and radial extent. Astron. J. 122, 1051–1066 (2001)

    Article  ADS  Google Scholar 

  5. Brown, M. E., Trujillo, C. & Rabinowitz, D. Discovery of a candidate inner Oort cloud planetoid. Preprint at 〈http://arXiv.org/astro-ph/0404456〉 (2004).

  6. Levison, H. F. & Duncan, M. J. From the Kuiper belt to Jupiter-family comets: The spatial distribution of ecliptic comets. Icarus 127, 13–32 (1997)

    Article  ADS  Google Scholar 

  7. Gladman, B. et al. Evidence for an extended scattered disk. Icarus 157, 269–279 (2002)

    Article  ADS  Google Scholar 

  8. Levison, H. & Morbidelli, A. The formation of the Kuiper belt by the outward transport of bodies during Neptune's migration. Nature 426, 419–421 (2003)

    Article  ADS  CAS  Google Scholar 

  9. Fernández, J. A. & Brunini, A. The buildup of a tightly bound comet cloud around an early Sun immersed in a dense Galactic environment: Numerical experiments. Icarus 106, 580–590 (2000)

    Article  ADS  Google Scholar 

  10. Ida, S., Larwood, J. & Burkert, A. Evidence for early stellar encounters in the orbital distribution of Edgeworth-Kuiper belt objects. Astrophys. J. 528, 351–356 (2000)

    Article  ADS  Google Scholar 

  11. Safronov, V. S. Evolution of the Protoplanetary Cloud and Formation of the Earth and Planets (Nauka, Moscow, 1969); English translation (NASA TT F-677, Coronet Books, Philadelphia, Pennsylvania, 1972).

  12. Wyatt, M. C., Dent, W. R. F. & Greaves, J. S. SCUBA observations of dust around Lindroos stars: evidence for a substantial submillimetre disc population. Mon. Not. R. Astron. Soc. 342, 876–888 (2003)

    Article  ADS  Google Scholar 

  13. Kenyon, S. J., Wood, K., Whitney, B. A. & Wolff, M. Forming the dusty ring in HR 4796A. Astrophys. J. 524, L119–L123 (1999)

    Article  ADS  Google Scholar 

  14. Kenyon, S. J. Planet formation in the outer solar system. Publ. Astron. Soc. Pacif. 114, 265–283 (2002)

    Article  ADS  Google Scholar 

  15. Brunini, A. & Melita, M. D. The existence of a planet beyond 50 AU and the orbital distribution of the classical Edgeworth-Kuiper-belt objects. Icarus 160, 32–43 (2002)

    Article  ADS  Google Scholar 

  16. Morbidelli, A. & Levison, H. Scenarios for the origin of the orbits of the trans-neptunian objects 2000 CR105 and 2003 VB12 (Sedna). Astron. J. 128, 2564–2576 (2004)

    Article  ADS  Google Scholar 

  17. Weidenschilling, S. J. Radial drift of particles in the solar nebula: implications for planetesimal formation. Icarus 165, 438–442 (2003)

    Article  ADS  Google Scholar 

  18. Youdin, A. N. & Shu, F. H. Planetesimal formation by gravitational instability. Astrophys. J. 580, 494–505 (2003)

    Article  ADS  Google Scholar 

  19. Adams, F. C., Hollenbach, D., Laughlin, G. & Gorti, U. Photoevaporation of circumstellar disks due to external far-ultraviolet radiation in stellar aggregates. Astrophys. J. 611, 360–379 (2004)

    Article  ADS  CAS  Google Scholar 

  20. Greaves, J. S. et al. A dust ring around ɛ Eridani: Analog to the young solar system. Astrophys. J. 506, L133–L137 (1998)

    Article  ADS  CAS  Google Scholar 

  21. Greaves, J. S., Wyatt, M. C., Holland, W. S. & Dent, W. R. F. The debris disc around τ Ceti: a massive analogue to the Kuiper belt. Mon. Not. R. Astron. Soc. 351, L54–L58 (2004)

    Article  ADS  CAS  Google Scholar 

  22. Kenyon, S. J. & Bromley, B. C. Collisional cascades in planetesimal disks. II. Embedded planets. Astron. J. 127, 513–530 (2004)

    Article  ADS  CAS  Google Scholar 

  23. Kenyon, S. J. & Bromley, B. C. The size distribution of Kuiper belt objects. Astron. J. 128, 1916–1926 (2004)

    Article  ADS  Google Scholar 

  24. Adams, F. C. & Laughlin, G. Constraints on the birth aggregate of the Solar System. Icarus 150, 151–162 (2001)

    Article  ADS  Google Scholar 

  25. Garcia-Sanchez, J. et al. Stellar encounters with the Oort cloud based on HIPPARCOS data. Astron. J. 117, 1042–1055 (1999)

    Article  ADS  Google Scholar 

  26. Toomre, A. & Toomre, J. Galactic bridges and tails. Astrophys. J. 178, 623–666 (1972)

    Article  ADS  Google Scholar 

  27. Barton, E. J., Bromley, B. C. & Geller, M. J. Kinematic effects of tidal interaction on galaxy rotation curves. Astrophys. J. 511, L25–L28 (1999)

    Article  ADS  Google Scholar 

  28. Girard, T. M., Grundy, W. M., Lopez, C. E. & van Altena, W. F. Relative proper motions and the stellar velocity dispersion of the open cluster M67. Astron. J. 98, 227–243 (1989)

    Article  ADS  Google Scholar 

  29. Bernstein, G. M. et al. The size distribution of trans-neptunian bodies. Astron. J. 128, 1364–1390 (2004)

    Article  ADS  Google Scholar 

  30. Brown, M. E. The inclination distribution of the Kuiper belt. Astron. J. 121, 2804–2814 (2001)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We acknowledge a generous allotment (of about 3,000 c.p.u. days) of computer time at the supercomputing centre at the Jet Propulsion Laboratory through funding from the NASA Offices of Mission to Planet Earth. Aeronautics and Space Science. Comments from M. Geller improved our paper. The NASA Astrophysics Theory Program supported part of this project.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Scott J. Kenyon.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Kenyon, S., Bromley, B. Stellar encounters as the origin of distant Solar System objects in highly eccentric orbits. Nature 432, 598–602 (2004). https://doi.org/10.1038/nature03136

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature03136

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