A paper published in Nature reports that the Cassini spacecraft has identified that moons Tethys and Dione are sources of plasma in Saturns magnetosphere. It appears that the moons are flinging great streams of particles into space, according to data from the NASA/ESA/ASI Cassini mission to Saturn. The discovery suggests the possibility of some sort of geological activity, perhaps even volcanic, on these icy worlds. The particles were traced to the two moons because of the dramatic movement of electrically charged gas in the magnetic environs of Saturn. Known as plasma, the gas is composed of negatively charged electrons and positively charged ions, which are atoms with one or more electrons missing. Because they are charged, the electrons and ions can become trapped inside a magnetic field. Saturn completes one rotation in just 10 hours and 46 minutes. This sweeps the magnetic field and the trapped plasma through space. The trapped gas feels a centrifugal force trying to throw it outwards, away from the centre of rotation. Soon after the Cassini spacecraft reached Saturn in June 2004, it revealed that the planets hurried rotation squashes the plasma into a disc and that great fingers of gas are being thrown out into space from the discs outer edges. Hotter, more tenuous plasma then rushes in to fill the gaps. Until this result, only Enceladus out of Saturns inner moons was known to be an active world, with huge geysers spraying gases hundreds of kilometres above the moons surface.
Imaging scientists on NASA's Cassini mission are telling a tale of how the small moons orbiting near the outer rings of Saturn came to be. The moons began as leftover shards from larger bodies that broke apart and filled out their "figures" with the debris that made the rings. It has long been suspected that Saturn's rings formed in the disintegration of one or several large icy bodies, perhaps pre-existing moons, by giant impacts. The resulting debris quickly spread and settled into the equatorial plane to form a thin disk surrounding the planet. And the small, irregularly shaped ring-region moons were believed to be the leftover pieces from this breakup.
Images of Saturn's Small Moons Tell the Story of Their Origins Imaging scientists on NASA's Cassini mission are telling a tale of how the small moons orbiting near the outer rings of Saturn came to be. The moons began as leftover shards from larger bodies that broke apart and filled out their "figures" with the debris that made the rings.
Now, several years' worth of cosmic images of Saturn's 14 known small moons have been used to derive the sizes and shapes of most of them, and in about half the cases, even masses and densities. This information, published in the Dec. 7 issue of the journal Science, has led to new insights into how some of these moons may have formed. The tip-off was the very low density of the inner moons, about half that of pure water ice, and sizes and shapes that suggested they have grown by the accumulation of ring material. The trouble was, these moons are within and near the rings, where it is not possible for small particles to fuse together gravitationally. So how did they do it? They got a jump start.
Satellites in the saturnian system are named for Greco-Roman titans, descendants of the titans, the Roman god of the beginning, and giants from Greco-Roman and other mythologies. Gallic, Inuit and Norse names identify three different orbit inclination groups, where inclinations are measured with respect to the ecliptic, not Saturn's equator or orbit. Retrograde satellites (those with an inclination of 90 to 180 degrees) are named for Norse giants (except for Phoebe, which was discovered long ago and is the largest). Prograde satellites with an orbit inclination of around 36 degrees are named for Gallic giants, and prograde satellites with an inclination of around 48 degrees are named for Inuit giants and spirits.
Saturn XLIX (Anthe)
One of the Alkyonides, the seven beautiful daughters of the Giant Alkyoneos.
The International astronomical combination (IAU) has announced new names of 4 satellites of Saturn (XLIX-LII).
Number
Satellite name
Temporary mark
Saturn XLIX
Anthe
S/2007 S 4
Saturn L
Jarnsaxa
S/2006 S 6
Saturn LI
Greip
S/2006 S 4
Saturn LII
Tarqeq
S/2007 S 1
Saturn satellite family, including uncertain ones, now numbers 63. Anthe is the 49th designated satellite, its name is derived from the daughter of a giant family [arukioneusu] which appears in the Greek myth. It was discovered in an image taken by the Cassini spaceprobe, ans announced in July 2007.
Satellite Jarnsaxa (50th) and Greip (51st), are retrograde satellites and orbit Saturn at a distance of approximately 1,800 kilometres. The name derives from European myth 51st Tarqeq is derived from Inuit myth.
Three of Saturn's moons, Titan at upper left, Dione at right and Janus just above the rings left of centre, are captured near the rings in this view from the Cassini spacecraft.
This view looks toward the unilluminated side of the rings from about 2 degrees above the ringplane. The planet is overexposed in this view. The image was taken in visible red light with the Cassini spacecraft wide-angle camera on June 24, 2007 at a distance of approximately 1.8 million kilometres from Saturn.
British scientists working with their NASA counterparts on a probe of Saturn have found a new moon circling that planet. Images of the new moon have been sent back by the Cassini-Huygens mission a joint venture between NASA and the European Space Agency - which set out on its epic journey to study Saturn in 1997. It took the shuttle seven years to get there and it has been orbiting the planet taking images since 2004.
Hyrrokkin, (Saturn XLIV, provisionaly designated S/2004 S 19) a satellite of Saturn which was discovery on June 26, 2006 has had it name corrected. It was originally listed as being spelled 'Hyrokkin'. It was named in April 2007 after Hyrrokkin, a Norse giantess.
Like a hawks eyes, the high resolution cameras on NASAs Cassini spacecraft have spotted yet another small, previously unknown moon circling giant Saturn and one which may indicate the existence of other small bodies in the same region. The tiny world--presently thought to be only about 2 kilometres wide--orbits at 197,700 kilometres from Saturn. Until a name for the moon is chosen by the International Astronomical Union, the moon has been given the provisional designation S/2007 S 4. The moon was first spotted in Cassini images taken on May 30, 2007. Subsequent searches through images taken by Cassini over the previous three years turned up additional detections of the moon and helped researchers refine their calculations of its orbital path.
Scientists have recently discovered that the planet Saturn is turning 60 - not years, but moons.
"We detected the 60th moon orbiting Saturn using the Cassini spacecraft's powerful wide-angle camera. I was looking at images of the region near the Saturnian moons Methone and Pallene and something caught my eye" - Carl Murray, a Cassini imaging team scientist from Queen Mary, University of London.