Kepler-421 : A Uranus-sized planet beyond the ice line.

Discovery of a Transiting Planet Near the Snow-Line
http://arxiv.org/abs/1407.4807

Quote :

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.

Another interesting result to come out of the HEK project.

Validated from only 2 transits (section 2.6 covers searching for expected transits that would have occurred if the period was an integer fraction of the interval)

http://spaceref.com/exoplanets/researchers-discover-transiting-exoplanet-with-longest-known-year.html

Kepler-421b is the transiting exoplanet with the longest known year. Kepler-421b circles its star once every 704 days.

And then there was a third transit...

Dalba & Muirhead "No Timing Variations Observed in Third Transit of Snow-Line Exoplanet Kepler-421b"
http://arxiv.org/abs/1606.09246