A Simplified Photodynamical Model for Planetary Mass Determination in Low-Eccentricity Multi-Transiting Systems

Abstract

Inferring planetary parameters from transit timing variations is challenging for small exoplanets because their transits may be so weak that determination of individual transit timing is difficult or impossible. We implement a useful combination of tools which together provide a numerically fast global photodynamical model. This is used to fit the TTV-bearing light-curve, in order to constrain the masses of transiting exoplanets in low eccentricity, multi-planet systems - and small planets in particular. We present inferred dynamical masses and orbital eccentricities in four multi-planet systems from Kepler's complete long-cadence data set. We test our model against Kepler-36 / KOI-277, a system with some of the most precisely determined planetary masses through TTV inversion methods, and find masses of 5.56 +0.41 -0.45 and 9.76 +0.79 -0.89 m_earth for Kepler-36 b and c, respectively - consistent with literature in both value and error. We then improve the mass determination of the four planets in Kepler-79 / KOI-152, where literature values were physically problematic to 12.5 +4.5 -3.6, 9.5 +2.3 -2:1, 11.3 +2.2 -2.2 and 6.3 +1.0 -1.0 m_earth for Kepler-79 b, c, d and e, respectively. We provide new mass constraints where none existed before for two systems. These are 12.5 +3.2 -2.6 m_earth for Kepler-450 c, and 3.3 +1.7 -1.0 and 17.4 +7.1 -3.8 m_earth for Kepler-595 c (previously KOI-547.03) and b, respectively. The photodynamical code used here, called PyDynamicaLC, is made publicly available.

References in corpus (28)

• MultiNest: an efficient and robust Bayesian inference tool for cosmology and particle physics
• Analytic Lightcurves for Planetary Transit Searches
• X-ray spectral modelling of the AGN obscuring region in the CDFS: Bayesian model selection and catalogue
• On detecting terrestrial planets with timing of giant planet transits
• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• EXOFAST: A fast exoplanetary fitting suite in IDL
• The California Kepler Survey VII. Precise Planet Radii Leveraging Gaia DR2 Reveal the Stellar Mass Dependence of the Planet Radius Gap
• False positive probabilties for all Kepler Objects of Interest: 1284 newly validated planets and 428 likely false positives
• Kepler-36: A Pair of Planets with Neighboring Orbits and Dissimilar Densities
• Extracting Planet Mass and Eccentricity From TTV data
• A Super-Earth Transiting a Naked-Eye Star
• Densities and Eccentricities of 139 Kepler Planets from Transit Time Variations
• Exoplanet Orbital Eccentricities Derived From LAMOST-Kepler Analysis
• Kepler Planet Masses and Eccentricities from TTV Analysis
• Transit Timing Observations from Kepler. IX. Catalog of the Full Long-Cadence Data Set
• TTVFast: An efficient and accurate code for transit timing inversion problems
• The Distribution of Transit Durations for Kepler Planet Candidates and Implications for their Orbital Eccentricities
• Secure TTV Mass Measurements: Ten Kepler Exoplanets between 3 and 8 Earth Masses with Diverse Densities and Incident Fluxes
• A Dynamical Analysis of the Kepler-80 System of Five Transiting Planets
• KOI-152's Low Density Planets
• Transit timing to first order in eccentricity
• Numerical and Analytical Modelling of Transit Time Variations
• Transit Timing Variations for Inclined and Retrograde Exoplanetary Systems
• An Independent Planet Search In The Kepler Dataset. I. A hundred new candidates and revised KOIs
• Mass and Eccentricity Constraints in the WASP-47 Planetary System from a Simultaneous Analysis of Radial Velocities & Transit Timing Variations
• A spectral approach to transit timing variations
• Modal Decomposition of TTV - Inferring Planet Masses and Eccentricities
• The Efficiency of Geometric Samplers for Exoplanet Transit Timing Variation Models

Cited by in corpus (13)

• A framework for the architecture of exoplanetary systems. I. Four classes of planetary system architecture
• Sculpting the sub-Saturn Occurrence Rate via Atmospheric Mass Loss
• A differentiable N-body code for transit timing and dynamical modeling. I. Algorithm and derivatives
• Physical Properties and Impact Parameter Variations of Kepler Planets from Analytic Light Curve Modeling
• An Accurate 3D Analytic Model for Exoplanetary Photometry, Radial Velocity, and Astrometry
• exoMMR: a New Python Package to Confirm and Characterize Mean Motion Resonances
• Planets similar in size are often dissimilar in interior
• A differentiable N-body code for transit timing and dynamical modelling -- II. Photodynamics
• Nauyaca: a new tool to determine planetary masses and orbital elements through transit timing analysis
• Evidence of a gap in the envelope mass fraction of sub-Saturns
• The Occurrence-weighted Median Planets Discovered by Transit Surveys Orbiting Solar-type Stars and Their Implications for Planet Formation and Evolution
• The Coupled Tidal Evolution of the Moons and Spins of Warm Exoplanets
• The TESS-Keck Survey. XI. Mass Measurements for Four Transiting sub-Neptunes orbiting K dwarf TOI-1246