Jason J. Wang, University of California, Berkeley
James R. Graham, University of California, Berkeley
Rebekah Dawson, Pennsylvania State University
Daniel Fabrycky, The University of Chicago
Robert J. De Rosa, University of California, Berkeley
Laurent Pueyo, Space Telescope Science Institute
Quinn Konopacky, Center for Astrophysics & Space Sciences
Bruce Macintosh, Kavli Institute for Particle Astrophysics and Cosmology
Christian Marois, National Research Council Canada
Eugene Chiang, University of California, Berkeley
S. Mark Ammons, Lawrence Livermore National Laboratory
Pauline Arriaga, University of California, Los Angeles
Vanessa P. Bailey, Jet Propulsion Laboratory
Travis Barman, The University of Arizona
Joanna Bulger, National Institutes of Natural Sciences - National Astronomical Observatory of Japan
Jeffrey Chilcote, University of Notre Dame
Tara Cotten, University of Georgia
Rene Doyon, Institut de Recherche sur les Exoplanètes
Gaspard Duchêne, University of California, Berkeley
Thomas M. Esposito, University of California, Berkeley
Michael P. Fitzgerald, University of California, Los Angeles
Katherine B. Follette, Amherst College
Benjamin L. Gerard, National Research Council Canada
Stephen J. Goodsell, Gemini Observatory
Alexandra Z. Greenbaum, University of Michigan, Ann Arbor
Pascale Hibon, European Southern Observatory Santiago
Li Wei Hung, US National Park Service
Patrick Ingraham, Large Synoptic Survey Telescope
Paul Kalas, University of California, Berkeley
James E. Larkin, University of California, Los Angeles
Jérôme Maire, Center for Astrophysics & Space Sciences
Franck Marchis, SETI Institute
Kimberly Ward-Duong, Arizona State UniversityFollow

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Publication Date


Publication Title

Astronomical Journal


The HR 8799 system uniquely harbors four young super-Jupiters whose orbits can provide insights into the system's dynamical history and constrain the masses of the planets themselves. Using the Gemini Planet Imager, we obtained down to one milliarcsecond precision on the astrometry of these planets. We assessed four-planet orbit models with different levels of constraints and found that assuming the planets are near 1:2:4:8 period commensurabilities, or are coplanar, does not worsen the fit. We added the prior that the planets must have been stable for the age of the system (40 Myr) by running orbit configurations from our posteriors through N-body simulations and varying the masses of the planets. We found that only assuming the planets are both coplanar and near 1:2:4:8 period commensurabilities produces dynamically stable orbits in large quantities. Our posterior of stable coplanar orbits tightly constrains the planets' orbits, and we discuss implications for the outermost planet b shaping the debris disk. A four-planet resonance lock is not necessary for stability up to now. However, planet pairs d and e, and c and d, are each likely locked in two-body resonances for stability if their component masses are above 6 M Jup and 7 M Jup, respectively. Combining the dynamical and luminosity constraints on the masses using hot-start evolutionary models and a system age of 42 ± 5 Myr, we found the mass of planet b to be 5.8 ± 0.5 M Jup, and the masses of planets c, d, and e to be each.


astrometry, planetdisk interactions, planets and satellites: dynamical evolution and stability, planets and satellites: gaseous planets, stars: individual (HR 8799), techniques: high angular resolution










© 2018. The American Astronomical Society


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