Discovery Ch

Did you mean:
Discoberi Ch
Charon

Charon's Pluto-facing hemisphere (determined from brightness variations during Pluto-Charon occultations)
Discovery
Discovered by:James W. Christy
Discovery date:June 22, 1978
Orbital characteristics 
Epoch 2,452,600.5
Semi-major axis:19,571 ± 4 km
Eccentricity:0.00000 ± 0.00007
Orbital period:6.3872304 ± 0.0000011 d
(6 d 9 h 17 m 36.7 ± 0.1 s)
Inclination:0°
(to Pluto's equator)
119.591 ± 0.014°
(to Pluto's orbit)
112.783 ± 0.014°
(to the ecliptic)
Longitude of ascending node:223.046 ± 0.014°
(to vernal equinox)
Satellite of:Pluto
Physical characteristics
Mean radius:603.5 ± 1.5 km
(0.095 Earths)
Surface area:4.58×106 km²
Mass:(1.52 ± 0.06)×1021 kg
(2.54×10−4 Earths)
Mean density:1.65 ± 0.06 g/cm³
Equatorial surface gravity:0.278 m/s2
Escape velocity:0.580 km/s
.36 mi/s
Rotation period:synchronous
Axial tilt:zero?
Albedo:varies between 0.36 and 0.39
Temperature:-220°C (53 K)
Apparent magnitude:16.8
Angular size:55 milli-arcsec

Charon (shair'-ən (key), IPA: /ˈʃeərən/, also kair'-ən, /ˈkeərən/; Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. With the discovery in 2005 of two other moons of Pluto (Nix and Hydra), Charon is now also referred to as Pluto I. The New Horizons mission is scheduled to visit Charon and Pluto in July 2015.

Charon should not be confused with the similarly named Chiron, a smaller object in the outer solar system.