Daphnis (moon)
From Wikipedia, the free encyclopedia
 Daphnis appearing as a small dot that causes ripples on the edges of the Keeler Gap in this image from the Cassini probe |
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| 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. |
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| 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
- IAUC 8524: Discovery announcement
- CICLOPS imaging: includes a movie of the moon's ripple effect
- Cassini-Huygens announcement
[edit] References
- ^ 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.
- ^ Based on diameters and density 0.5 - 2 g/cm³
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| Pan · Daphnis · Atlas · Prometheus · S/2004 S 6 · S/2004 S 4 · S/2004 S 3 · Pandora · Epimetheus and Janus Mimas · Methone · Pallene · Enceladus · Telesto, Tethys, and Calypso · Helene, Dione, and Polydeuces · Rhea · Titan · Hyperion · Iapetus Kiviuq · Ijiraq · Phoebe · Paaliaq · Skathi · Albiorix · S/2004 S 11 · Erriapo · S/2006 S 8 · Siarnaq · S/2004 S 13 · S/2006 S 4 · Tarvos S/2004 S 19 · Mundilfari · S/2006 S 6 · S/2006 S 1 · S/2004 S 17 · Narvi · S/2004 S 15 · S/2004 S 10 · Suttungr · S/2004 S 12 · S/2004 S 18 S/2004 S 9 · S/2004 S 14 · S/2004 S 7 · Thrymr · S/2006 S 3 · S/2006 S 7 · S/2006 S 2 · S/2004 S 16 · S/2006 S 2 · Ymir · S/2006 S 5 · S/2004 S 8 |
| See also: Pronunciation key | Rings of Saturn | Cassini-Huygens | Themis |
