With 62 newly discovered moons, Saturn surpasses Jupiter to become the planet with the most moons in the Solar System.
Prior to this discovery, Saturn had 83 moons recognized by the International Astronomical Union (IAU). Currently, this number has increased to 145, as reported by Space on May 12. This also marks an important milestone for Saturn, making it the first known celestial body in the universe to have more than 100 moons orbiting it.
Hubble Space Telescope image of Saturn from June 2018. (Image: NASA/ESA/A. Simon (GSFC)/OPAL Team/J. DePasquale (STScI)).
Edward Ashton, a postdoctoral researcher at the Institute of Astronomy and Astrophysics at Academia Sinica, along with collaborators, discovered these new moons, which are relatively small and faint, using a technique known as “shift and stack.” This technique employs a series of moving images at the same speed as the moon’s movement across the sky, enhancing the signal from the moon. As a result, moons that were too faint to be seen in individual images could be revealed in the “stacked images.”
Astronomers have used this method to search for moons around the giant ice planets Neptune and Uranus, but this is the first time it has been applied to Saturn, the second largest planet in the Solar System.
In this new study, the team utilized data collected by the Canada-France-Hawaii Telescope (CFHT) on Mauna Kea, Hawaii, from 2019 to 2021. This data helped them discover moons around Saturn with diameters as small as 2.5 kilometers.
Although astronomers observed some of the moons in early 2019, they required additional information to confirm that these were indeed moons and not asteroids approaching Saturn. Therefore, they monitored them for several years to ensure they were truly orbiting this giant gas planet.
The newly discovered moons are classified as “irregular moons.” This term refers to objects that are influenced by the gravitational pull of a planet and orbit that planet in larger, flatter, or more elliptical inclined orbits compared to regular moons. Saturn currently has 121 irregular moons and 24 regular moons.
In February, Jupiter surpassed Saturn to claim the title of “moon king” after 12 new moons were confirmed, raising its total to 92. Saturn has now reclaimed the crown with 145 moons. However, this title may continue to change hands as astronomers’ moon detection technology advances.
