Skathi: A Tiny Moon of Saturn
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Saturn, the sixth planet from the sun, is well-known for its stunning rings, but it also possesses a group of enigmatic and exotic moons. One of these is Skathi, which was spotted in 2000 by a team of astronomers led by Brett Gladman. In this paper, we will examine Skathi's features, how it was discovered, and what distinguishes it from other moons.
A Retrograde Irregular Moon of Saturn
Skathi is an irregular retrograde moon of the planet Saturn discovered on September 23, 2000, by Brett Gladman and his team of astronomers. Along with seven other satellites of Saturn (Tarvos, Ijiraq, Thrymr, Siarnaq, Mundilfari, Erriapus, and Suttungr), the team announced their discovery on December 7, 2000. Skathi is a member of the Norse group of Saturn's irregular moons, and its origin remains an unresolved question.
One possibility is that it originated as an asteroid that formed elsewhere and was subsequently captured by the gravitational pull of Saturn during a flyby. Another possibility is that it was originally a fragment of one of Saturn's moons, like Phoebe, that broke off during a collision and became a separate satellite. Although its physical makeup remains unknown, it is known to measure about 8 kilometers (5 miles) in diameter and possess an irregular shape.
Skathi Facts
- Mass (kg): 314,720,370,950,411
- Radius (km): 3.2
- Density (gm/cm3): 2.3
- Distance from planet (km): 15,641,000
- Rotational period (days): Unknown
- Orbital period (days): 725.784
- Orbital velocity (km/sec): Unknown
- Eccentricity of orbit: 0.246
- Inclination of orbit (°): 149° to the ecliptic (154° to Saturn's equator)
- Albedo: 0.06
- Magnitude (Vo): Unknown
- Atmosphere: Unknown
Discovery
Skathi was discovered on September 23, 2000, by a team of astronomers using adaptive optics with the 3.6-m Canada-France-Hawaii reflector on Mauna Kea, Hawaii. At the same time, the team discovered seven additional moons orbiting Saturn: Tarvos, Ijiraq, Thrymr, Siarnaq, Mundilfari, Erriapus, and Suttungr. The moon is named after the Norse goddess Skadi, who is linked to winter, hunting, and skiing.
Skathi was discovered on September 23, 2000, by a team of astronomers led by Brett Gladman. The team announced its discovery on December 7, 2000, along with seven other satellites of Saturn: Tarvos, Ijiraq, Thrymr, Siarnaq, Mundilfari, Erriapus, and Suttungr. Skathi was temporarily designated as S/2000 S 8.
Skathi's Name
The name Skathi is commonly known as Skadi, although the former was initially announced in IAU Circular 8177. The IAU Working Group on Planetary System Nomenclature (WGPSN) chose to use an alternative transliteration of the Norse spelling. The classical spelling is Skaði, with the letter Ð (eth), and the original form Skadi was a graphical approximation of that.
Skathi's Orbit
Skathi orbits Saturn at an average distance of 15,576 megameters in 725.784 days. It has an inclination of 149° to the ecliptic (154° to Saturn's equator) and follows a retrograde path with an eccentricity of 0.246.
Characteristics
Skathi is identified as one of Saturn's irregular moons, belonging to the Norse group of satellites. Its diameter is estimated to be 8 km, denoting its position as one of Saturn's smallest moons. As a retrograde irregular moon of Saturn, Skathi orbits in the opposite direction to the planet's rotation. Like other of Saturn’s irregular moons, Skathi is believed to have been captured by Saturn's gravity rather than having formed from the dusty disk that surrounded the newly formed planet as is thought to have occurred with the regular moons. Skathi seems to belong to a subgroup that also includes Skoll, Hyrrokkin, S/2006 S1, Bergelmir, Farbauti, S/2006 S3, and Kari.
Skathi has an irregular shape and a diameter of approximately 6.4 kilometers. Its equatorial radius measures 4 kilometers and its equatorial circumference is 25.1 kilometers. The object has an albedo of 0.06, which represents the amount of radiation that it reflects into space.
In some aspects, Skathi's orbit is comparable to those of Saturn's irregular moons, however, it differs substantially by being abnormally rapid, even for an irregular satellite of Saturn, and displaying a smaller semi-major axis than every other retrograde moon of Saturn except Phoebe.
By the Numbers
Here are some quick facts about Skathi:
- Discovered: September 23, 2000
- Discoverers: Brett J. Gladman, John J. Kavelaars, Jean-Marc Petit, Hans Scholl, Matthew J. Holman, Brian G. Marsden, Phillip D. Nicholson, and Joseph A. Burns
- Mean radius: 4.0 km
- Surface area: ~200 km²
- Volume: ~33 km³
- Mass: ~2.5 × 10¹² kg
- Mean density: ~0.5 g/cm³
- Surface gravity: ~0.0003 m/s²
- Escape velocity: ~0.0006 km/s
- Rotation period: Unknown
- Axial tilt: Unknown
- Albedo: Unknown
Skathi's Membership in the Norse Group of Moons
Skathi is a member of the Norse group of moons orbiting Saturn, characterized by their retrograde motion that is opposite to the planet's rotation. These moons are known as "irregular" due to their unusual orbits.
Conclusion
Skathi is a tiny moon of Saturn that was discovered in 2000. It is a member of the Norse group of moons and has a retrograde orbit around Saturn. Skathi is unique among Saturn's irregular moons in some important ways, such as its unusually fast orbit and smaller semi-major axis. Although Skathi is small and dim, it is still an important object for astronomers to study as they seek to understand the mysteries of our solar system.
Skathi is an irregular retrograde moon of the It is one of the several moons orbiting Saturn and was discovered on September 23, 2000, by a group of astronomers led by Brett Gladman. Skathi has a diameter of approximately 6.4 kilometers and an irregular shape. Its physical composition has yet to be determined, but its width is known to measure around 8 kilometers (5 miles). The origin of Skathi remains unanswered; however, it could have formed due to substantial impacts on Phoebe, resulting in ejected material.