http://newsroom.fit.edu/2016/07/21/alien-solar-system-boasts-tightly-spaced-planets-unusual-orbits/
Located about 1,100 light years away, Kepler-80, named for the NASA telescope that discovered it,
features five small planets orbiting in extreme proximity to their star. MacDonald and Ragozzine
determined the nature of the exoplanetary system through measurements taken with the telescope.
As early as 2012, Kepler scientists found that all five planets orbit in an area about 150 times smaller
than the Earth’s orbit around the Sun, with “years” of about one, three, four, seven and nine days. The
planets’ close proximity to each other and their star allowed the Kepler Space Telescope to detect tiny
variations (about 0.001 percent) in the length of their “years” due to their mutual gravitational interactions.