New (sort of) moon of Neptune

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https://www.cbc.ca/news/technology/n...camp-1.5025091


http://blogs.discovermagazine.com/d-...Hippocamp1.jpg

Astronomers Officially Name the Newest Moon of Neptune
Hippocamp may have been forged by the fallout of an impact billions of years ago.

Scientists have discovered a tiny moon orbiting Neptune, bringing the planet’s total number of known satellites to 14.

In keeping with the convention of naming Neptune’s moons after water deities, the newly described world is called Hippocamp, after a mythological equine sea creature.

Hippocamp is only about 34 kilometers (21 miles) in diameter, making it the runt of the Neptunian family. It is one of seven inner moons of Neptune, a group that tightly orbits the planet roughly once every day.


When the Voyager 2 spacecraft passed by Neptune in 1989, it discovered six moons in Neptune’s inner orbit. Neptune is also orbited by seven other satellites located in more distant and irregular trajectories.

Hippocamp, the second farthest of the inner moons from Neptune, managed to stay hidden from the Voyager probe because of its dimness and suboptimal camera angles.


In 2013, Mark Showalter, a senior research scientist at the SETI (Search for Extraterrestrial Intelligence) Institute, pinpointed Hippocamp in images captured by the Hubble Space Telescope. It took years to confirm its physical and orbital details, and decide on an official name (previously the moon was known alternately as S/2004 N 1 or Neptune XIV).

Showalter and his colleagues announced the official name, and published their other findings, on Wednesday in Nature.

The researchers think that the new moon might have formed after a comet collided with Proteus, the largest of Neptune’s inner moons, which is about 4,000 times the size of Hippocamp.

Hippocamp is close to Proteus, orbiting about 12,000 kilometers inside the trajectory of its hypothetical mother world. Proteus also happens to bear a giant impact crater called Pharos, which stretches at least 230 kilometers (143 miles) across its surface. Showalter and his colleagues suggest that Hippocamp could be made from broken-off debris from the Pharos event, which accumulated into a new small object.


The earliest Hubble image of Hippocamp, taken in 2004. Image: Mark R. Showalter, SETI Institute
“The discovery of tiny Hippocamp contributes to our understanding of the history of Neptune’s inner system,” the researchers wrote in the study. “Proteus and Hippocamp were even closer in the past because Proteus is migrating outwards owing to tidal interactions with Neptune.”

“It is therefore worth exploring the possible connection between these moons,” they added.



https://www.space.com/21977-neptune-...fographic.html