The 55 Cancri planetary system: Fully self-consistent N-body constraints and a dynamical analysis

Benjamin E. Nelson, Eric B. Ford, Jason T. Wright, Debra A. Fischer, Kaspar von Braun, Andrew W. Howard, Matthew J. Payne, Saleh Dindar

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

We present an updated study of the planets known to orbit 55 Cancri A using 1 418 highprecision radial velocity observations from four observatories (Lick, Keck, Hobby-Eberly Telescope, Harlan J. Smith Telescope) and transit time/durations for the inner-most planet, 55 Cancri 'e' (Winn et al. 2011). We provide the first posterior sample for the masses and orbital parameters based on self-consistent N-body orbital solutions for the 55 Cancri planets, all of which are dynamically stable (for at least 108 yr). We apply a GPU version of Radial velocity Using N-body Differential evolution Markov Chain Monte Carlo (RUN DMC; Nelson, Ford & Payne) to perform a Bayesian analysis of the radial velocity and transit observations. Each of the planets in this remarkable system has unique characteristics. Our investigation of high-cadence radial velocities and priors based on space-based photometry yields an updated mass estimate for planet 'e' (8.09 ± 0.26 M), which affects its density (5.51±1.001.32 g cm-3) and inferred bulk composition. Dynamical stability dictates that the orbital plane of planet 'e' must be aligned to within 60° of the orbital plane of the outer planets (which we assume to be coplanar). The mutual interactions between the planets 'b' and 'c' may develop an apsidal lock about 180°. We find 36-45 per cent of all our model systems librate about the anti-aligned configuration with an amplitude of 51°±10°. Other cases showed short-term perturbations in the libration of ωb - ωc, circulation, and nodding, but we find the planets are not in a 3:1 mean-motion resonance. A revised orbital period and eccentricity for planet 'd' pushes it further towards the closest known Jupiter analogue in the exoplanet population.

Original languageEnglish (US)
Pages (from-to)442-451
Number of pages10
JournalMonthly Notices of the Royal Astronomical Society
Volume441
Issue number1
DOIs
StatePublished - Jan 1 2014

Fingerprint

planetary systems
planets
planet
radial velocity
orbitals
analysis
telescopes
Bayesian analysis
libration
Markov chains
transit time
extrasolar planets
Markov chain
transit
Jupiter (planet)
eccentricity
Jupiter
photometry
observatories
observatory

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Nelson, Benjamin E. ; Ford, Eric B. ; Wright, Jason T. ; Fischer, Debra A. ; Braun, Kaspar von ; Howard, Andrew W. ; Payne, Matthew J. ; Dindar, Saleh. / The 55 Cancri planetary system : Fully self-consistent N-body constraints and a dynamical analysis. In: Monthly Notices of the Royal Astronomical Society. 2014 ; Vol. 441, No. 1. pp. 442-451.
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The 55 Cancri planetary system : Fully self-consistent N-body constraints and a dynamical analysis. / Nelson, Benjamin E.; Ford, Eric B.; Wright, Jason T.; Fischer, Debra A.; Braun, Kaspar von; Howard, Andrew W.; Payne, Matthew J.; Dindar, Saleh.

In: Monthly Notices of the Royal Astronomical Society, Vol. 441, No. 1, 01.01.2014, p. 442-451.

Research output: Contribution to journalArticle

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