Astronomer Identifies Neptune’s 14th Moon
Some persistent detective work by SETI astronomer Mark Showalter turned up a tiny new moon of Neptune, the distant blue-green planet’s 14th.
Showalter made the discovery July 1 after tracking the movement of a white dot that surfaced over and over again in 150 archival photographs of Neptune taken by the Hubble Space Telescope between 2004 and 2009, NASA and the Space Telescope Science Institute announced on Monday.
S/2004 N1 measures less than 12 miles across. At 65,400 miles from Neptune, the newly christened moon circles once every 23 hours and circles within the orbits of two other moons, Larissa and Proteus. Showalter made the finding while studying the traces of moons and arcs, or partial rings aroundNeptune.
“The moons and arcs orbit very quickly, so we had to devise a way to follow their motion in order to bring out the details of the system,” he said in a statement. “It’s the same reason a sports photographer tracks a running athlete — the athlete stays in focus, but the background blurs.”
Showalter found what the NASA probe Voyager 2 missed as it streaked byNeptune in 1989.
Neptune’s largest moon, Triton, which is nearly the size of Earth’s moon, may be a captured icy dwarf planet from the Kuiper Belt at the outer rim of our solar system, according to NASA’s announcement. This capture would have gravitationally torn up any original satellite systemNeptune possessed. Many of the moons now seen orbiting the planet probably formed after Triton settled into its unusual retrograde orbit about Neptune.