Daphnis (moon)

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Daphnis appearing as a small dot that
causes ripples on the edges of the Keeler Gap
in this image from the Cassini probe
Discovery
Discovered by Cassini Imaging Science Team
Discovered in May 6, 2005
Orbital characteristics [1]
Semimajor axis 136,504.98±0.02 km
Eccentricity ≈ 0
Orbital period 0.5940800 d
Inclination
(to Saturn's equator)		 ≈ 0°
Is a satellite of Saturn
Physical characteristics
Mean diameter 6 − 8 km
Mass 5 − 50 ×1013 kg[2]
Mean density unknown
Surface gravity unknown
Rotation period synchronous
Axial tilt unknown
Albedo ≈ 0.5
Surface temp.
min mean max
 ? K ~78 K  ? K
Atmosphere none

Daphnis (IPA: [ˈdæfnəs], Greek Δαφνίς) is an inner satellite of Saturn. It is also known as Saturn XXXV; its provisional designation was S/2005 S 1. Daphnis is about 6 to 8 kilometres in diameter, and orbits the planet in the Keeler Gap within the A ring. It is named after Daphnis, a shepherd, pipes player, and pastoral poet in Greek mythology. He was the son of Hermes, brother of Pan, and descendant of the Titans.

Its discovery was announced by Carolyn Porco and the Cassini Imaging Science Team on May 6, 2005, in six images taken by the Cassini probe over 16 min on May 1 from a time-lapse sequence of 0.180 second narrow-angle-camera exposures of the outer edge of the A ring. It was subsequently found in 32 low-phase images taken of the F ring on April 13 (spanning 18 min) and again in two high-resolution (3.54 km/pixel) low-phase images taken on May 2, when its 7 km disk was resolved. It had previously been inferred from gravitational ripples observed on the outer edge of the Keeler gap. This moon seems to make waves inside the ring.

The inclination and eccentricity of Daphnis' orbit are very close to zero, and are not distinguishable from it with present data. Daphnis has an estimated albedo of 50%.

[edit] External links

[edit] References

  1. ^ J.N. Spitale et al (2006). "The orbits of Saturn's small satellites derived from combined historic and Cassini imaging observations". The Astronomical Journal 132: 692. 
  2. ^ Based on diameters and density 0.5 - 2 g/cm³
... | Pan | Daphnis | Atlas | ...
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