Neptune and its moons

[Rick]

Neptune's kidnap puzzle 'cracked'

Neptune's moon Triton used to be paired with another object, but was torn from its companion during capture by the eighth planet's gravitational field.

This is the new model put forward to explain the moon's present location.

More: http://news.bbc.co.uk/1/hi/sci/tech/4758091.stm
Also: http://www.theregister.co.uk/2006/05/12/neptune_triton/

[mickw]

Odd Cloud on Neptune Seen Splitting Into Two

A cloudy patch that is typically seen over the south pole of Neptune was spotted in double by astronomers after it briefly split in two, as viewed by ground-based telescopes in 2007.

The cloud feature has been seen near Neptune's south pole since the Voyager 2 spacecraft visited the planet in the late 1980s. But what exactly it was and what processes on the planet generated it weren't known then, as telescopes on Earth can't see Neptune well enough to resolve such small features.

"What we knew about it was that there was a spot," said Mate Ádámkovics, a researcher at the University of California, Berkeley and a member of the team that made the new observations.

More:   Space.com

[mickw]

Neptune Nears End of First Orbit Since Its Discovery in 1846

The planet Neptune will be in opposition — when the sun, Earth, and a planet fall in a straight line on Aug. 20. The planet will be exactly opposite the sun in the sky, being highest in the sky at local midnight. Usually this is also the point where the planet is closest to the Earth.

This opposition is special because Neptune will be returning close to the spot where it was discovered in 1846, marking its first complete trip around the sun since its discovery.

More:   It's about time

[Mike]

New Moon Discovered Around Neptune in Old Hubble Images

Our blue and gassy outer planet Neptune hosted 13 known moons until today. Now, there are 14.

The new moon, known as S/2004 N1, is so small and faint that it escaped detection by NASA's Voyager 2 spacecraft, which flew by Neptune in 1989.

Just 12 miles across, the moon orbits outside the planet's ring system, carving a rut into space about 65,400 miles away from the ice giant. But S/2004 N1 is a little speed demon: It completes its 372,000-mile orbital journey in just 23 hours.

"This is a moon that never sits still long enough to get its picture taken," said the SETI Institute's ace moon-finder Mark Showalter, who discovered the moon while studying long-exposure, archival images taken by the Hubble Space Telescope. It's one of a half-dozen moons Showalter has found, including Mab and Cupid around Uranus, Saturn's shepherd moon Pan, and the two tiniest of Pluto's moons, newly named Kerberos and Styx.

Does finding moons ever get boring? Nope. "It's a rush," Showalter said.


Showalter first spied something that could have been a new Neptunian moon on July 1. He'd been studying the planet's rings, and thought to look a bit farther out. "There was this little dot sitting there," he said. "It looked like it could be a moon."

Because S/2004 N1 is so dim, Showalter needed some time to confirm the moon's presence. After aligning and combining about 15 sets of Hubble images taken between 2004 and 2009, he determined that the dot was, in fact, a moon. Roughly 150 images helped him plot the satellite's orbit. "You can't see it in the individual images, but when you combine images, it turns up," he said. "It turns up very consistently."

MORE.....

[Rick]

Archival Hubble Images Reveal Neptune's "Lost" Inner Moon

Neptune's tiny, innermost moon, Naiad, has now been seen for the first time since it was discovered by Voyager's cameras in 1989. Dr. Mark Showalter, a senior research scientist at the SETI Institute in Mountain View, California, announced the result today in Denver, Colorado, at the annual meeting of the Division for Planetary Sciences of the American Astronomical Society. He and collaborators Dr. Jack Lissauer of the NASA Ames Research Center, Dr. Imke de Pater of UC Berkeley, and Robert French of the SETI Institute, also released a dramatic new image of Neptune's puzzling rings and ring-arcs, which were first imaged by Voyager.

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