A team of astronomers led by the University of Hawaii Institute for Astronomy (UH IfA) has discovered a planet three times the mass of Jupiter in a distant planetary system.
The discovery is based on six years of data taken at W. M. Keck Observatory on Maunakea in Hawaii. Using the High-Resolution Echelle Spectrometer (HIRES) instrument on the 10-meter Keck I telescope, the team confirmed that the planet, named Kepler-88 d, orbits its star every four years, and its orbit is not circular, but elliptical. At three times the mass of Jupiter, Kepler-88 d is the most massive planet in this system.
The system, Kepler-88, was already famous among astronomers for two planets that orbit much closer to the star, Kepler-88 b and c (planets are typically named alphabetically in the order of their discovery).
Those two planets have a bizarre and striking dynamic called mean motion resonance. The sub-Neptune sized planet b orbits the star in just 11 days, which is almost exactly half the 22-day orbital period of planet c, a Jupiter-mass planet.
The newly discovered planet adds another dimension to astronomers' understanding of the system.