Discovery of a Transiting Planet Near the Snow-Line

Abstract

In most theories of planet formation, the snow-line represents a boundary between the emergence of the interior rocky planets and the exterior ice giants. The wide separation of the snow-line makes the discovery of transiting worlds challenging, yet transits would allow for detailed subsequent characterization. We present the discovery of Kepler-421b, a Uranus-sized exoplanet transiting a G9/K0 dwarf once every 704.2 days in a near-circular orbit. Using public Kepler photometry, we demonstrate that the two observed transits can be uniquely attributed to the 704.2 day period. Detailed light curve analysis with BLENDER validates the planetary nature of Kepler-421b to >4 sigmas confidence. Kepler-421b receives the same insolation as a body at ~2AU in the Solar System and for a Uranian albedo would have an effective temperature of ~180K. Using a time-dependent model for the protoplanetary disk, we estimate that Kepler-421b's present semi-major axis was beyond the snow-line after ~3Myr, indicating that Kepler-421b may have formed at its observed location.

14 pages, 10 figures, 3 tables. Accepted in ApJ

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Cited by in corpus (11)

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• A novel method for identifying exoplanetary rings
• Five Planets Transiting a Ninth Magnitude Star
• Solar System Physics for Exoplanet Research
• Validation of small Kepler transiting planet candidates in or near the habitable zone
• The Interstellar Medium in the Kepler Search Volume
• No Timing Variations Observed in Third Transit of Snow-Line Exoplanet Kepler-421b
• Life on Exoplanets In the Habitable Zone of M-Dwarfs?
• Out-of-Transit Refracted Light in the Atmospheres of Transiting and Non-Transiting Exoplanets
• Parameter estimation from the transit light curve including gravitational lensing effects