A bright inner moon of Neptune that has been missing in action since 1989 has been spotted, astronomers said Tuesday.
Credit for the re-discovery of Naiad, the giant plant's closest moon, goes to Mark Showalter, with the SETI Institute in Mountain View, Calif., and colleagues who devised a new way to analyze archived Hubble Space Telescope images.
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Astronomers have been on the hunt for Naiad, which orbits about 30,000 miles away from Neptune, since it was discovered in photographs snapped by NASA's visiting Voyager 2 spacecraft in 1989.
"There's a reason we had so much trouble finding it. It's in the wrong place," Showalter told reporters during a webcast press conference at the American Astronomical Society meeting in Denver on Tuesday.
Based on analysis of Naiad's orbit extrapolated from Voyager 2 data, astronomers had expected to find the moon about 80 degrees away from where it actually turned up in archived 2004 Hubble images.
"That's a surprisingly large amount," Showalter said.