Setebos (moon)

Setebos /ˈsɛtɛbʌs/ is one of the outermost retrograde irregular satellites of Uranus. It was discovered on 18 July 1999 by John J. Kavelaars et al. and provisionally designated S/1999 U 1.^[8]

Animation of discovery images taken in July 1999

Setebos

Discovery image of Setebos (encircled)
Discovery
Discovered by	John J. Kavelaars Brett J. Gladman Matthew J. Holman Jean-Marc Petit Hans Scholl
Discovery date	July 18, 1999
Designations
Designation	Uranus XIX
Pronunciation	/ˈsɛtɛbʌs/,[1] /-bɒs/[2]
Adjectives	Setebosian /ˌsɛtɛˈboʊsiən/[3]
Orbital characteristics
Mean orbit radius	17,418,000 km[4][5]
Eccentricity	0.5914[5]
Orbital period (sidereal)	2225.21 d
Inclination	158° (to the ecliptic)[4]
Satellite of	Uranus
Physical characteristics
Mean radius	24 km (estimate)[6] <50 km[7]
Surface area	~7200 km2 (estimate)
Volume	~58,000 km3 (estimate)
Mass	~7.5×1016 kg (estimate)
Mean density	~1.3 g/cm3 (assumed)
Surface gravity	~0.0063 m/s2 (estimate)
Escape velocity	~0.0204 km/s (estimate)
Synodic rotation period	4.255 ± 0.017 h[7]
Axial tilt	?
Albedo	0.04 (assumed)[6]
Temperature	~65 K (estimate)

Confirmed as Uranus XIX, it is named after the god Setebos worshipped by Caliban and Sycorax in William Shakespeare's play The Tempest.

The orbital parameters suggest that it may belong to the same dynamic cluster as Sycorax and Prospero, suggesting common origin.^[9] However, this suggestion does not appear to be supported by the observed colours. The satellite appears neutral (grey) in visible light (colour indices B−V = 0.77 , R−V = 0.35 ),^[10] similar to Prospero but different from Sycorax (which is light red).

A crater on Umbriel is also named after Setebos, but with the spelling Setibos.

See also

• Setebos
• Moons of Uranus
• Irregular satellites