PH3, also known as Kepler-289, is the 3rd system with planets found by Planet Hunters using Kepler data. Gravitational effects of two planets cause a third middle one to transit at highly irregular intervals, the first such planet found. The star is a young 1BYO sun-like star, 2300 ly away. First planet a has 35 day period and twice as large and 7 as massive as Earth and could be rocky, ocean-filled, or gas giant hybrid. Planet c is somewhat further out (0.33 AU, 2.5 RE, 4 ME, density similar to Jupiter) and is a new member of the small low-density class that require significant hydrogen/helium. Planet d is a gas giant at 0.55 AU, 12 RE, 132 ME. The middle planet has an orbital period ratio of 1.91 with both the inner and outer planets.