Titania (moon)

Infobox Planet
name = Titania
alt_names = Uranus III
adjectives = Titanian


caption = Click image for description
bgcolour = #a0ffa0
discovery = yes
discoverer = William Herschel
discovered = January 11, 1787
semimajor = 435 910 km
mean_orbit_radius = 436 300 km
eccentricity = 0.0011
period = 8.706 d
inclination = 0.340° (to Uranus' equator)
satellite_of = Uranus
physical_characteristics = yes
mean_radius = 788.9 km (0.1237 Earths)
surface_area = 7 820 000 km²
volume = 2 057 000 000 km³
mass = 3.526e|21 kg (5.9e|-4 Earths)
density = 1.72 g/cm³
surface_grav = 0.378 m/s² (~0.039 g)
escape_velocity = 0.77 km/s
rotation = presumed synchronous
axial_tilt = 0
albedo = 0.27
magnitude = 13.73
single_temperature = ~60 K

Titania (pron-en|tɨˈtɑːnjə respell|ti|TAH|nyə, also IPAlink-en|taɪˈteɪniə respell|tye|TAY|nee-ə) is the largest moon of Uranus and the eighth largest moon in the Solar System.

Discovery

Titania was discovered on January 11, 1787 by William Herschel. He reported it and Oberon the same year. [Herschel, "An Account of the Discovery of Two Satellites Revolving Round the Georgian Planet", "Philosophical Transactions of the Royal Society of London", Vol. 77, pp. 125-129, 1787; and "On George's Planet and its satellites", "Philosophical Transactions of the Royal Society of London", Vol. 78, pp. 364-378, 1788.] He later reported four more satellites, which turned out to be spurious. ["On the Discovery of Four Additional Satellites of the Georgium Sidus; The Retrograde Motion of Its Old Satellites Announced; And the Cause of Their Disappearance at Certain Distances from the Planet Explained", "Philosophical Transactions of the Royal Society of London", Vol. 88, pp. 47-79, 1798.]

Name and pronunciation

The names of Titania and the other four satellites of Uranus then known were suggested by Herschel's son John Herschel in 1852 at the request of William Lassell, who had discovered Ariel and Umbriel the year before. [ [http://adsabs.harvard.edu//full/seri/AN.../0034//0000169.000.html http://adsabs.harvard.edu//full/seri/AN.../0034//0000169.000.html] "Adsabs.harvard.edu" Retrieved on 05-19-07 ] Lassell had earlier endorsed Herschel's 1847 naming scheme for the seven then-known satellites of Saturn and had named his newly-discovered eighth satellite Hyperion in accordance with Herschel's naming scheme in 1848.

All of the moons of Uranus are named for characters from Shakespeare or Alexander Pope. Titania was named after Titania, the Queen of the Faeries in "A Midsummer Night's Dream".

Shakespeare's character's name is pronounced IPA|/tɨˈtɑːnjə/, but the moon is often IPA|/taɪˈteɪniə/, by analogy with the familiar chemical element titanium. The adjectival form, "Titanian," is homonymous with that of Saturn's moon Titan.

It is also called Uranus III.

Physical characteristics

So far the only close-up images of Titania are from the "Voyager 2" probe, which photographed the moon during its Uranus flyby in January, 1986. At the time of the flyby the southern hemisphere of the moon was pointed towards the Sun; the northern hemisphere was unobservable.

Although its interior composition is uncertain, one model suggests that Titania is composed of roughly 50% water ice, 30% silicate rock, and 20% methane-related organic compounds. A major surface feature is a huge canyon that dwarfs the scale of the Grand Canyon on Earth and is in the same class as the Valles Marineris on Mars or Ithaca Chasma on Saturn's moon Tethys.

Scientists recognise the following geological features on Titania:
* Chasmata (chasms)
* Craters
* Rupes (scarps)

Occultation

On September 8, 2001, Titania occulted a faint star; this was an opportunity to both refine its diameter and ephemeris, and to detect any extant atmosphere. The data revealed no atmosphere to a surface pressure of 0.03 microbars; if it exists, it would have to be far thinner than that of Triton or Pluto. [ [http://www.obspm.fr/actual/nouvelle/mar02/titania.en.shtml http://www.obspm.fr/actual/nouvelle/mar02/titania.en.shtml] "Obspm.fr" Retrieved on 05-19-07 ] [ [http://www.lesia.obspm.fr/~titania/results.html http://www.lesia.obspm.fr/~titania/results.html] "Lesia.obspm.fr" Retrieved on 05-19-07 ]

ee also

*List of geological features on Titania
*Titania in fiction

Notes

External links

* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Ura_Titania Titania Profile] by [http://solarsystem.nasa.gov NASA's Solar System Exploration]