Credit: NASA/JPL/Space Science Institute

NASA recently published an intriguing sequence of images, acquired by the Saturn-bound Cassini spacecraft, showing the discovery of the 60th moon of Saturn. It is expected that more new Saturnian moons would be discovered with continued observation.

The discovery suggests that the new moon, along with neighboring small moons, Methone and Pallene, may form part of a larger group of moons in this region of the Saturnian system.

Preliminary estimates show the moon to be approximately 2 km across, with an orbit that lies between those of Methone (about 3 km across) and Pallene (about 4 km across). The Moon's orbit is in resonance with another moon, Mimas (nearly 400 km across). Mimas is visible in this sequence as a bright, moving object. The red box highlights the new moon's location.

Saturn's G ring is visible as a narrow arc. The whitish glow that extends across the scene is due to scattered light within the camera optics.

Another tiny Saturnian moon, Calypso, is also visible in the sequence. Calypso (about 15 km across) is a Trojan moon of Tethys. A Trojan moon shares the orbit of a larger moon. It orbits the parent planet near gravitationally stable points, preceding or lagging behind the larger moon.

This view looks down on the dark side of the rings from about 3° above the ringplane.

The series of images was taken in visible light with Cassini's wide-angle camera on 30 May 2007, at a distance of approximately 1.76 million km from Saturn. Image scale is about 105 km per pixel. An animation of this sequence is linked below.

The tally of planetary moons is now 166. Jupiter has the largest family of moons in the Solar System, with 63 moons.

Further Information

Animation

http://www.nasa.gov/images/content/182594main_PIA08369_full_movie.gif

Out from the Shadows: Two New Saturnian Moons

http://nssdc.gsfc.nasa.gov/planetary/text/cassini_pr_20040816.txt

The Cassini-Huygens Mission

http://nssdc.gsfc.nasa.gov/planetary/text/cassini_pr_20040816.txt

Aymen Mohamed Ibrahem

Senior Astronomy Specialist