Stephano (moon)

Stephano (/ˈstɛfənoʊ/ STEF-ən-oh) is a retrograde irregular satellite of Uranus. It was discovered by Brett J. Gladman, et al. in 1999, and given the provisional designation S/1999 U 2.^{[7][8][9][10][11]}

Stephano

Discovery image of Stephano (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 XX
Pronunciation	/ˈstɛfənoʊ/ STEF-ən-oh[1][2]
Adjectives	Stephanonian /ˌstɛfəˈnoʊniən/ STEF-ə-NOH-nee-ən[3]
Orbital characteristics[4]
Mean orbit radius	7 951 400 km
Eccentricity	0.235
Orbital period (sidereal)	677 d
Inclination	143.6° (to the ecliptic)
Satellite of	Uranus
Group	Caliban group
Physical characteristics
Mean radius	16 km (estimate)[5]
Surface area	~3200 km2 (estimate)
Volume	~17 000 km3 (estimate)
Mass	~2.2×1016 kg (estimate)
Mean density	~1.3 g/cm3 (assumed)
Surface gravity	~0.006 m/s2 (estimate)
Escape velocity	~0.014 km/s (estimate)
Synodic rotation period	?
Axial tilt	?
Albedo	0.04 (assumed)[5]
Temperature	~65 K (estimate)
Spectral type	B–V = 0.97 ± 0.07, V–R = 0.66 ± 0.05[6]

Confirmed as Uranus XX, it was named after the drunken butler in William Shakespeare's play The Tempest in August 2000.^[12]

The orbital parameters suggest that it may belong to the same dynamic cluster as Caliban, suggesting a common origin.^[13]

Animation of several irregular moons' orbits around Uranus, including that of Stephano's.
   Uranus  ·    Sycorax ·    Francisco  ·    Caliban  ·    Stephano  ·    Trinculo

Animation of discovery images taken by the CFHT in July 1999

See also

• Uranus's natural satellites
• Irregular satellites