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Title: Discovery of a transiting planet near the snow-line

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 >4σ confidence. Kepler-421b receives the same insolation as a body at ∼2 AU in the solar system, as well as a Uranian albedo, which would have an effective temperature of ∼180 K. 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 ∼3 Myr, indicating that Kepler-421b may have formed at its observed location.
Authors:
; ; ;  [1] ; ;  [2] ; ; ;  [3] ;  [4] ;  [5]
  1. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)
  2. NASA Ames Research Center, Moffett Field, CA 94035 (United States)
  3. University of California, Berkeley, CA 94720 (United States)
  4. Department of Physics and Astronomy, Vanderbilt University, 1807 Station B, Nashville, TN 37235 (United States)
  5. Physics Department, Fisk University, 1000 17th Ave. N, Nashville, TN 37208 (United States)
Publication Date:
OSTI Identifier:
22370335
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 795; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ALBEDO; DETECTION; DWARF STARS; EARTH PLANET; GLOBAL ASPECTS; ICE; INSOLATION; ORBITS; PHOTOMETRY; PROTOPLANETS; SATELLITES; SOLAR SYSTEM; STARS; TIME DEPENDENCE; URANUS PLANET; VISIBLE RADIATION