Space

Say hello to Hippocamp, Neptune's newest moon

Say hello to Hippocamp, Neptun...
An illustration of Hippocamp, a newly-discovered moon of Neptune
An illustration of Hippocamp, a newly-discovered moon of Neptune
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A size comparison of Neptune's inner moons
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A size comparison of Neptune's inner moons
Hippocamp was discovered in Hubble data dating as far back as 2004
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Hippocamp was discovered in Hubble data dating as far back as 2004
Hippocamp was discovered using new image processing techniques that allow astronomers to smooth out motion blur, caused by fast-moving objects
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Hippocamp was discovered using new image processing techniques that allow astronomers to smooth out motion blur, caused by fast-moving objects
Astronomers have named and described a tiny new moon orbiting Neptune
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Astronomers have named and described a tiny new moon orbiting Neptune
An illustration of Hippocamp, a newly-discovered moon of Neptune
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An illustration of Hippocamp, a newly-discovered moon of Neptune

Neptune's collection of moons has officially grown to 14. Originally discovered in 2013 and designated S/2004 N 1, this tiny world is described more accurately in a new paper, which also gives it an origin story and, finally, a catchier name. Say hello to Hippocamp.

In 2013, the moon was first spotted in Hubble images taken in 2009, but it was later found to have cropped up in data dating all the way back to 2004 – hence its designation. Over the last few years, the original discoverer Mark Showalter has led a team to study the object in more detail.

With a diameter of about 34 km (21 mi), Hippocamp is by far Neptune's smallest satellite. That said, it's almost twice as large as earlier estimates. Its tiny size is probably how it evaded detection for so long, even avoiding the eye of Voyager 2, which whizzed through the neighborhood in 1989 and discovered six other moons.

Continuing the nautical theme of Neptune and its many moons, the new name "Hippocamp" comes from the creature of Greek mythology that's half-horse, half-fish.

A size comparison of Neptune's inner moons
A size comparison of Neptune's inner moons

It orbits within the inner group of Neptune's moons, and seems to stick pretty close to Proteus, the biggest of that bunch. Because of that, the researchers suggest that Hippocamp is actually an ancient fragment of Proteus, which may have splintered off after an impact by a comet or asteroid.

The moon's existence was only confirmed through special image-processing techniques that allowed the team to smooth out the motion blur caused by the fast-moving objects. The researchers say this method could aid in the search for other moons or exoplanets.

A paper on the research was published in the journal Nature.

Source: SETI Institute

2 comments
VincentWolf
How can such a small body be perfectly spherical
GregVoevodsky
These should be called Dwarf Moons. Why is any size rock considered a moon? Is our space debris considered man-made moons too?