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Images of a fourth planet orbiting HR 8799

Nature volume 468, pages 10801083 (23 December 2010) | Download Citation

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Abstract

High-contrast near-infrared imaging of the nearby star HR 8799 has shown three giant planets1. Such images were possible because of the wide orbits (>25 astronomical units, where 1 au is the Earth–Sun distance) and youth (<100 Myr) of the imaged planets, which are still hot and bright as they radiate away gravitational energy acquired during their formation. An important area of contention in the exoplanet community is whether outer planets (>10 au) more massive than Jupiter form by way of one-step gravitational instabilities2 or, rather, through a two-step process involving accretion of a core followed by accumulation of a massive outer envelope composed primarily of hydrogen and helium3. Here we report the presence of a fourth planet, interior to and of about the same mass as the other three. The system, with this additional planet, represents a challenge for current planet formation models as none of them can explain the in situ formation of all four planets. With its four young giant planets and known cold/warm debris belts4, the HR 8799 planetary system is a unique laboratory in which to study the formation and evolution of giant planets at wide (>10 au) separations.

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Acknowledgements

We thank the Keck staff, particularly H. Lewis, B. Goodrich and J. Lyke, for support with the follow-up observations. We thank G. Laughlin and D.C. Fabrycky for discussions. Portions of this research were performed under the auspices of the US Department of Energy by LLNL and also supported in part by the NSF Center for Adaptive Optics. We acknowledge support by NASA grants to UCLA, LLNL and Lowell Observatory. The data were obtained at the W.M. Keck Observatory. This publication makes use of data products from the Two Micron All Sky Survey and the SIMBAD database.

Author information

Affiliations

  1. National Research Council Canada, Herzberg Institute of Astrophysics, 5071 West Saanich Road, Victoria, British Columbia V9E 2E7, Canada

    • Christian Marois
  2. Physics & Astronomy Department, University of California, Los Angeles, California 90095, USA

    • B. Zuckerman
  3. Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA

    • Quinn M. Konopacky
    •  & Bruce Macintosh
  4. Lowell Observatory, 1400 West Mars Hill Road, Flagstaff, Arizona 86001, USA

    • Travis Barman

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Contributions

The authors contributed equally to this work.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Christian Marois.

Supplementary information

PDF files

  1. 1.

    Supplementary Information

    The file contains Supplementary Tables 1-2 showing the stable configurations (30Myr and 60 Myr) found for the HR 8799 4-planet system.

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https://doi.org/10.1038/nature09684

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