Charon (moon)
.jpg)
Charon in approximate true color as viewed by New Horizons on 13 July 2015
|
|
| Discovery | |
|---|---|
| Discovered by | James W. Christy |
| Discovery date | 22 June 1978 |
| Designations | |
| Pronunciation | /ˈʃærən/ SHARR-ən or /ˈkɛərən/ KAIR-ən |
|
Named after
|
Charon |
| (134340) Pluto I | |
| Adjectives | Charonian |
| Orbital characteristics | |
| Epoch 2452600.5 | |
| 17536±4 km to system barycenter, 19571±4 km to the center of Pluto | |
| Eccentricity | 0.00 |
|
6.3872304±0.0000011 d (6 d, 9 h, 17 m, 36.7 ± 0.1 s) |
|
|
Average orbital speed
|
0.21 km/s |
| Inclination |
0.001° (to Pluto's equator) 119.591°±0.014° (to Pluto's orbit) 112.783°±0.014° (to the ecliptic) |
| 223.046°±0.014° (to vernal equinox) | |
| Satellite of | Pluto |
| Physical characteristics | |
|
Mean radius
|
606±3 km(0.095 Earths, 0.51 Plutos) |
| Flattening | <1% |
| 4.×106 km2 (0.0090 Earths) | |
| Volume | (9.32±0.14)×108 km3 (0.00086 Earths) |
| Mass |
(1.586±0.015)×1021 kg (2.66×10−4 Earths) (12.2% of Pluto) |
|
Mean density
|
1.707±0.013 g/cm3 |
| 0.288 m/s2 | |
|
0.59 km/s 0.37 mi/s |
|
| synchronous | |
| Albedo | 0.2 to 0.5 at a solar phase angle of 15° |
| Temperature | −220 °C (53 K) |
| 16.8 | |
| 1 | |
| 55 milli-arcsec | |
Charon, also known as (134340) Pluto I, is the largest of the five known natural satellites of the dwarf planet Pluto. It was discovered in 1978 at the United States Naval Observatory in Washington, D.C., using photographic plates taken at the United States Naval Observatory Flagstaff Station (NOFS). With half the diameter and one eighth the mass of Pluto, it is a very large moon in comparison to its parent body. Its gravitational influence is such that the barycenter of the Pluto–Charon system lies outside Pluto. In September 2016, astronomers announced that the reddish-brown cap of the north pole of Charon is composed of tholins, organic macromolecules that may be essential ingredients of life, and produced from methane, nitrogen and related gases released from the atmosphere of Pluto and transferred over about 19,000 km (12,000 mi) distance to the orbiting moon. The New Horizons spacecraft is the only probe that has visited the Pluto system. It approached Charon to within 27,000 km (17,000 mi).
Charon was discovered by United States Naval Observatory astronomer James Christy, using the 1.55-meter telescope at NOFS, and was formally announced to the world via the International Astronomical Union on July 7, 1978 On June 22, 1978, he had been examining highly magnified images of Pluto on photographic plates taken at the 1.55-meter (61 in) Flagstaff telescope two months prior. Christy noticed that a slight elongation appeared periodically. Later, the bulge was confirmed on plates dating back to April 29, 1965.
...
Wikipedia