A Search for Additional Planets in the NASA EPOXI Observations of the Exoplanet System GJ 436

Abstract

We present time series photometry of the M dwarf transiting exoplanet system GJ 436 obtained with the the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission. We conduct a search of the high-precision time series for additional planets around GJ 436, which could be revealed either directly through their photometric transits, or indirectly through the variations these second planets induce on the transits of the previously known planet. In the case of GJ 436, the presence of a second planet is perhaps indicated by the residual orbital eccentricity of the known hot Neptune companion. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series, we rule out transiting planets larger than 1.5 R_Earth interior to GJ 436b with 95% confidence, and larger than 1.25 R_Earth with 80% confidence. Assuming coplanarity of additional planets with the orbit of GJ 436b, we cannot expect that putative planets with orbital periods longer than about 3.4 days will transit. However, if such a planet were to transit, we rule out planets larger than 2.0 R_Earth with orbital periods less than 8.5 days with 95% confidence. We also place dynamical constraints on additional bodies in the GJ 436 system. Our analysis should serve as a useful guide for similar analyses for which radial velocity measurements are not available, such as those discovered by the Kepler mission. These dynamical constraints on additional planets with periods from 0.5 to 9 days rule out coplanar secular perturbers as small as 10 M_Earth and non-coplanar secular perturbers as small as 1 M_Earth in orbits close in to GJ 436b. We present refined estimates of the system parameters for GJ 436. We also report a sinusoidal modulation in the GJ 436 light curve that we attribute to star spots. [Abridged]

29 pages, 8 figures, 3 tables, accepted for publication in ApJ

References in corpus (32)

• DHP Framework: Digital Health Passports Using Blockchain -- Use case on international tourism during the COVID-19 pandemic
• Mass-Radius Relationships for Solid Exoplanets
• A super-Earth transiting a nearby low-mass star
• Transiting exoplanets from the CoRoT space mission VIII. CoRoT-7b: the first Super-Earth with measured radius
• Tidal Evolution of Close-in Extra-Solar Planets
• Homogeneous studies of transiting extrasolar planets. I. Light curve analyses
• The Transit Light Curve Project. IX. Evidence for a Smaller Radius of the Exoplanet XO-3b
• Exotic Earths: Forming Habitable Worlds with Giant Planet Migration
• The Transit Light Curve (TLC) Project. I. Four Consecutive Transits of the Exoplanet XO-1b
• Spitzer Transit and Secondary Eclipse Photometry of GJ 436b
• Accurate Spitzer infrared radius measurement for the hot Neptune GJ 436b
• Minimum Radii of Super-Earths: Constraints from Giant Impacts
• The M Dwarf GJ 436 and its Neptune-Mass Planet
• The transiting exoplanet host star GJ 436: a test of stellar evolution models in the lower main sequence, and revised planetary parameters
• Using long-term transit timing to detect terrestrial planets
• Observational Constraints on Trojans of Transiting Extrasolar Planets
• Characterization of the hot Neptune GJ 436b with Spitzer and ground-based observations
• Observability of the General Relativistic Precession of Periastra in Exoplanets
• A transit timing analysis of nine RISE light curves of the exoplanet system TrES-3
• A ~5 M_earth Super-Earth Orbiting GJ 436?: The Power of Near-Grazing Transits
• A limit on the presence of Earth-mass planets around a Sun-like star
• Periastron Precession Measurements in Transiting Extrasolar Planetary Systems at the Level of General Relativity
• Limits to the planet candidate GJ 436c
• Transit infrared spectroscopy of the hot neptune around GJ 436 with the Hubble Space Telescope
• A Hubble Space Telescope transit light curve for GJ436b
• MOST Spacebased Photometry of the Transiting Exoplanet System HD 189733: Precise Timing Measurements for Transits Across an Active Star
• A Quasi-Stationary Solution to Gliese 436b's Eccentricity
• MOST Spacebased Photometry of the Transiting Exoplanet System HD 209458: Transit Timing to Search for Additional Planets
• An analysis of the transit times of CoRoT-1b
• Looking for Super-Earths in the HD 189733 System: A Search for Transits in Most Space-Based Photometry
• New Observations and a Possible Detection of Parameter Variations in the Transits of Gliese 436b
• High Cadence Near Infrared Timing Observations of Extrasolar Planets: I. GJ 436b and XO-1b

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