October 2018
Vol 4, Issue 10

About The Cover

Cover image expansion

COVER While the existence of exomoons—moons orbiting extrasolar planets—is probable, direct observational evidence of that existence has been elusive. Previous observations made using NASA's Kepler space telescope offered suggestions that Kepler-1625b, a Jupiter-sized planet orbiting the Solar-mass yellow star Kepler-1625, may be orbited by an exomoon. Now, Teachey and Kipping report additional observations made using the Hubble Space Telescope, as well as a refined analysis of Kepler photometry data, that strongly support the exomoon hypothesis. Their work suggests that this moon, if it exists, would be similar in size to Neptune or Uranus in our own Solar System. While the authors caution that their results must be confirmed by subsequent studies, the moon of Kepler-1625b ultimately could be the first confirmed exomoon. [CREDIT: DAN DURDA, FELLOW, INTERNATIONAL ASSOCIATION OF ASTRONOMICAL ARTISTS]