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A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

Abstract

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto1. It resides at present at 95.7 astronomical units (1 au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163 ± 6 kilometres, density 2.52 ± 0.05 grams per cm3 and a high visible geometric albedo, . No nitrogen, argon or methane atmospheres are detected with surface pressure larger than 1 nanobar, about 10,000 times more tenuous than Pluto's present atmosphere2,3,4,5. As Pluto's radius is estimated3,4,5,6,7,8 to be between 1,150 and 1,200 kilometres, Eris appears as a Pluto twin, with a bright surface possibly caused by a collapsed atmosphere, owing to its cold environment. We anticipate that this atmosphere may periodically sublimate as Eris approaches its perihelion, at 37.8 astronomical units from the Sun.

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Figure 1: Eris occultation light curves.
Figure 2: Measuring Eris' size.
Figure 3: Upper limit on Eris' atmosphere.

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References

  1. Tegler, S. C. et al. Methane and nitrogen abundances on Pluto and Eris. Astrophys. J. 725, 1296–1305 (2010)

    Article  ADS  CAS  Google Scholar 

  2. Yelle, R. V. & Elliot, J. L. in Pluto and Charon (eds Stern, S. A. & Tholen, D. J. ) 347–390 (Univ. Arizona Press, 1997)

    Google Scholar 

  3. Elliot, J. L. et al. Changes in Pluto's atmosphere: 1988–2006. Astron. J. 134, 1–13 (2007)

    Article  ADS  CAS  Google Scholar 

  4. Lellouch, E. et al. Pluto's lower atmosphere structure and methane abundance from high-resolution spectroscopy and stellar occultations. Astron. Astrophys. 495, L17–L21 (2009)

    Article  ADS  CAS  Google Scholar 

  5. Zalucha, M. A. et al. An analysis of Pluto occultation light curves using an atmospheric radiative–conductive model. Icarus 211, 804–818 (2011)

    Article  ADS  CAS  Google Scholar 

  6. Tholen, D. J. & Buie, M. W. Further analysis of Pluto-Charon mutual event observations. Bull. Am. Astron. Soc. 22, 1129 (1990)

    ADS  Google Scholar 

  7. Young, E. F. & Binzel, R. P. A new determination of radii and limb parameters for Pluto and Charon from mutual event lightcurves. Icarus 108, 186–199 (1994)

    Article  ADS  Google Scholar 

  8. Tholen, D. J. & Buie, M. W. in Pluto and Charon (eds Stern, S.A. & Tholen, D.J. ) 193–219 (Univ. Arizona Press, 1997)

    Google Scholar 

  9. Brown, M. E., Trujillo, C. A. & Rabinowitz, D. L. Discovery of a planetary-sized object in the scattered Kuiper Belt. Astrophys. J. 635, L97–L100 (2005)

    Article  ADS  CAS  Google Scholar 

  10. Brown, M. E., Schaller, E. L., Roe, H. G., Rabinowitz, D. L. & Trujillo, C. A. Direct measurement of the size of 2003 UB313 from the Hubble Space Telescope. Astrophys. J. 643, L61–L63 (2006)

    Article  ADS  CAS  Google Scholar 

  11. Bertoldi, F. F. Altenhoff, W. Weiss, A., Menten, K. M. & Thum, C. The trans-neptunian object UB313 is larger than Pluto. Nature 439, 563–564 (2006)

    Article  ADS  CAS  Google Scholar 

  12. Brown, M. E. & Schaller, E. L. The mass of dwarf planet Eris. Science 316, 1585 (2007)

    Article  ADS  CAS  Google Scholar 

  13. Sheppard, S. S. et al. Light curves of dwarf plutonian planets and other large Kuiper Belt Objects: their rotations, phase functions, and absolute magnitudes. Astron. J. 134, 787–798 (2007)

    Article  ADS  Google Scholar 

  14. Duffard, R. et al. A study of photometric variations on the dwarf planet (136199) Eris. Astron. Astrophys. 479, 877–881 (2008)

    Article  ADS  Google Scholar 

  15. Assafin, M. et al. Precise predictions of stellar occultations by Pluto, Charon, Nix and Hydra for 2008–2015. Astron. Astrophys. 515, A32 (2010)

    Article  Google Scholar 

  16. Rabinowitz, M. E. et al. Photometric observations constraining the size, shape, and albedo of 2003 EL61, a rapidly rotating, Pluto-sized object in the Kuiper Belt. Astrophys. J. 639, 1238–1251 (2006)

    Article  ADS  Google Scholar 

  17. Lacerda, P. & Jewitt, D. C. Densities of solar system objects from their rotational light curves. Astron. J. 133, 1393–1408 (2007)

    Article  ADS  Google Scholar 

  18. 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 

  19. Tholen, D. J., Buie, M. W., Grundy, W. M. & Elliott, G. T. Masses of Nix and Hydra. Astron. J. 135, 777–784 (2008)

    Article  ADS  Google Scholar 

  20. Verbiscer, A., French, R., Showalter, M. & Helfenstein, P. Enceladus: cosmic graffiti artist caught in the act. Science 315, 815 (2007)

    Article  ADS  CAS  Google Scholar 

  21. Elliot, J. L. et al. Size and albedo of Kuiper belt object 55636 from a stellar occultation. Nature 465, 897–900 (2010)

    Article  ADS  CAS  Google Scholar 

  22. Stansberry, J. et al. in The Solar System beyond Neptune (eds Barucci, M. A., Boehnhardt, H., Cruikshank, D. P. & Morbidelli, A. ) 161–179 (Univ. Arizona Press, 2008)

  23. Howett, C. J. A., Spencer, J. R., Pearl, J. & Segura, M. Thermal inertia and bolometric Bond albedo values for Mimas, Enceladus, Tethys, Dione, Rhea and Iapetus as derived from Cassini/CIRS measurements. Icarus 206, 573–593 (2010)

    Article  ADS  Google Scholar 

  24. Brucker, M. J. et al. High albedos of low inclination classical Kuiper belt objects. Icarus 201, 284–294 (2009)

    Article  ADS  Google Scholar 

  25. Müller, T. G. et al. “TNOs are cool”: a survey of the trans-Neptunian region. I. Results from the Herschel science demonstration phase (SDP). Astron. Astrophys. 518, L146 (2010)

    Article  ADS  Google Scholar 

  26. Lellouch, E. et al. “TNOs are cool”: a survey of the trans-Neptunian region. II. The thermal lightcurve of (136108) Haumea. Astron. Astrophys. 518, L147 (2010)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank W. M. Owen and S. Preston for providing astrometric updates on the occulted star just before the observations, and I. Belskaya and M. E. Brown for discussions when writing the paper. We acknowledge support from the French grant ‘Beyond Neptune’ and from the Institut Universitaire de France. J.L.O., A.J.C.-T., L.C. and M.T.E. acknowledge funding from Spanish AYA grants and FEDER funds. TRAPPIST is a project funded by the Belgian Fund for Scientific Research (FRS-FNRS) with the participation of the Swiss National Science Foundation (SNF). J.I.B.C. acknowledges CNPq and FAPERJ grants. F.B.-R. acknowledges the support of CDFB/CAPES, Brazil. W.J.B.C., W.R. and F.P.S. thank the Brazilian Agency FAPEMIG.

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Authors and Affiliations

Authors

Contributions

B.S. helped plan the campaign, centralized the stellar occultation predictions, participated in the observations, analysed data, wrote and ran the diffraction, limb-fitting and ray-tracing codes, and wrote part of the paper. J.L.O. helped plan the campaign, analysed data for the prediction, participated in the observations, obtained and analysed data, and wrote part of the paper. E.L. analysed the implications of the results for the Eris thermal model, albedo constraints and putative atmospheric structure, and wrote part of the paper. M.A., F.B.-R., A.H.A., J.I.B.C., R.V.M., D.N.d.S.N. and R.B. discovered the star candidate and analysed data for the predictions. E.J. and A.M. obtained and analysed the positive occultation detection at La Silla/TRAPPIST and San Pedro/Harlingten telescopes, respectively. F.B.-R., F.C., M.G. and J.M. analysed data, D.H. calculated Dysnomia’s position at the moment of occultation and wrote part of the paper. All other authors participated in the planning of the campaign and/or the observations, and the authors listed in Supplementary Table 2 were responsible for the observations. All authors were given the opportunity to review the results and comment on the manuscript.

Corresponding author

Correspondence to B. Sicardy.

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The authors declare no competing financial interests.

Supplementary information

Supplementary Information

This file contains Supplementary Text and Data 1-7, Supplementary Figures 1- 5 with legends, Supplementary Tables 1-5 and additional references. This file was replaced on 20 December to reinstate the type missing from the top of page 5. (PDF 489 kb)

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Sicardy, B., Ortiz, J., Assafin, M. et al. A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation. Nature 478, 493–496 (2011). https://doi.org/10.1038/nature10550

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