Mark Showalter, a researcher at the SETI Institute [seti.org] in Mountain View, analzying Hubble images of Neptune has revealed a previously undetected moon [nytimes.com], bringing the icy blue planet's count to 14.
The new moon, is dubbed Hippocamp, after the fish tailed horses from Greek Mythology.
The discovery was published in the journal Nature [nature.com]
Mark...did not set out to make this discovery. He was analyzing Neptune’s rings with a new technique to process old images that essentially twisted them while adding them together. That allowed him to better see the rings, which are both faint and quick-moving.
On a whim, he decided to apply that same technique to other parts of the image he produced. To his surprise, a tiny white dot appeared.
Further analyses have confirmed that it is a moon, and a rather odd one.
Hippocamp is flat, tiny (only 527 ice hockey rinks in diameter, or about 20 miles), and in a fast orbit that is too near to Proteus. This leads to speculation that it was a fragment broken free from Proteus billions of years ago by an impact, possibly with some refugee from the Kuiper belt.
[This provides] further support for the hypothesis that the inner Neptune system has been shaped by numerous impacts.
Flat and icy, whatever could we use that for?