Kepler-90 is a Sun-like star, but all of its eight planets are scrunched into the equivalent distance of Earth to the Sun. The inner planets have extremely tight orbits with a “year” on Kepler-90i lasting only 14.4 days. In comparison, Mercury’s orbit is 88 days. Consequently, Kepler-90i has an average surface temperature of 800 degrees Fahrenheit, and is not a likely place for life as we know it. The structure of the Kepler-90’s system hints that the eight planets around Kepler-90 may have formed more spread out, like the planets in our own solar system, and then somehow migrated to the orbits we see them in today.
Credit: NASA/Ames Research Center/Wendy Stenzel