Dynamical Constraints on the HR 8799 Planets with GPI

Jason J. Wang, James R. Graham, Rebekah Dawson, Daniel Fabrycky, Robert J. De Rosa, Laurent Pueyo, Quinn Konopacky, Bruce Macintosh, Christian Marois, Eugene Chiang, S. Mark Ammons, Pauline Arriaga, Vanessa P. Bailey, Travis Barman, Joanna Bulger, Jeffrey Chilcote, Tara Cotten, Rene Doyon, Gaspard Duchêne, Thomas M. EspositoMichael P. Fitzgerald, Katherine B. Follette, Benjamin L. Gerard, Stephen J. Goodsell, Alexandra Z. Greenbaum, Pascale Hibon, Li Wei Hung, Patrick Ingraham, Paul Kalas, James E. Larkin, Jérôme Maire, Franck Marchis, Mark S. Marley, Stanimir Metchev, Maxwell A. Millar-Blanchaer, Eric L. Nielsen, Rebecca Oppenheimer, David Palmer, Jennifer Patience, Marshall Perrin, Lisa Poyneer, Abhijith Rajan, Julien Rameau, Fredrik T. Rantakyrö, Jean Baptiste Ruffio, Dmitry Savransky, Adam C. Schneider, Anand Sivaramakrishnan, Inseok Song, Remi Soummer, Sandrine Thomas, J. Kent Wallace, Kimberly Ward-Duong, Sloane Wiktorowicz, Schuyler Wolff

Research output: Contribution to journalArticle

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Abstract

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.

Original languageEnglish (US)
Article number192
JournalAstronomical Journal
Volume156
Issue number5
DOIs
StatePublished - Nov 2018

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Wang, J. J., Graham, J. R., Dawson, R., Fabrycky, D., De Rosa, R. J., Pueyo, L., Konopacky, Q., Macintosh, B., Marois, C., Chiang, E., Ammons, S. M., Arriaga, P., Bailey, V. P., Barman, T., Bulger, J., Chilcote, J., Cotten, T., Doyon, R., Duchêne, G., ... Wolff, S. (2018). Dynamical Constraints on the HR 8799 Planets with GPI. Astronomical Journal, 156(5), [192]. https://doi.org/10.3847/1538-3881/aae150