 Hubble Space Telescope image of Typhon and its moon Echidna, taken in 2006 | |
| Discovery | |
|---|---|
| Discovered by | NEAT |
| Discovery date | 5 February 2002 |
| Designations | |
| (42355) Typhon | |
| Pronunciation | /ˈtaɪfɒn/[1] |
Named after | ΤυφώνTyphōn |
| 2002 CR46 | |
| SDO[2][3] Centaur[4] | |
| Adjectives | Typhonian/taɪˈfoʊniən/[5] |
| Symbol | .svg) (rare) |
| Orbital characteristics[2] | |
| Epoch 13 January 2016 (JD 2457400.5) | |
| Uncertainty parameter 2 | |
| Observation arc | 9563 days (26.18 yr) |
| Aphelion | 58.982252 AU (8.8236193 Tm) |
| Perihelion | 17.545721 AU (2.6248025 Tm) |
| 38.263987 AU (5.7242110 Tm) | |
| Eccentricity | 0.5414560 |
| 236.70yr (86453.7d) | |
| 14.61898075° | |
| 0° 0m 14.991s / day | |
| Inclination | 2.4252078° |
| 351.9098598° | |
| 159.3215723° | |
| Knownsatellites | 1 (Echidna) |
| TJupiter | 4.692 |
| Physical characteristics | |
| 162±7 km[6] | |
| Mass | (9.49±0.52)×1017 kg[7] |
Meandensity | 0.66+0.09 −0.08 g/cm3[8] |
| 9.67 h (0.403 d)[8] | |
| 0.044±0.003[6] | |
| B−R=1.29±0.07[6] V−I=0.99±0.04[7] | |
| 7.72±0.004[6] | |
42355 Typhon (/ˈtaɪfɒn/;provisional designation2002 CR46) is ascattered disc object that was discovered on February 5, 2002, by theNEAT program. It measures162±7 km in diameter, and is named afterTyphon, a monster inGreek mythology. Typhon is the first known binarycentaur,[9] using an extended definition of acentaur as an object on a non-resonant (unstable) orbit with the perihelion inside the orbit of Neptune.[10]
Planetary symbols are no longer much used in astronomy, so Typhon never received a symbol in the astronomical literature. There is no standard symbol for Typhon used by astrologers either. A hurricane symbol (.svg)
) has been used, which might be identified withU+1F300 🌀︎CYCLONE (U+FE0E ︎VARIATION SELECTOR-15 is used to make the character display as text).[11]
Measurements of its thermal radiation led to an equivalent diameter of about either138±9 km or185±7 km, with the latter value preferable.[8] The diameter of the central body (Typhon) is in the latter case162±7 km.[6] Due to its small size, it is unlikely to be classified as adwarf planet. As of 2021, no rotationallightcurve has been analyzed and the body's actual shape remain unknown.
Typhon has a BR taxonomic class, with a blue surface. It has a resulting B–R color difference of about 1.3,[6] while V–I color difference is about unity.[7] The spectra of Typhon show the presence of water ice and possibly of water altered silicates.[12]
| Discovery | |
|---|---|
| Discovery date | 2006 |
| Designations | |
| (42355) Typhon I | |
| Pronunciation | /ɪˈkɪdnə/[13] |
Named after | Έχιδνα |
| Adjectives | Echidnian[14] Echidnean (rarely)[15] (both/ɪˈkɪdniən/)[16] |
| Orbital characteristics | |
| ~1300 km | |
| 11 d | |
| Satellite of | Typhon |
| Physical characteristics | |
| Dimensions | 89±6 km |
A largemoon was identified in 2006.[7] It is namedEchidna (formal designation(42355) Typhon I), afterthe monstrous mate of Typhon. It orbits Typhon at the distance of1628±29 km, completing one orbit in18.9709±0.0064 days. Its diameter is estimated at89±6 km.[6] Echidna has the same color as Typhon.[7]
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