42355 Typhon

42355 Typhon
Hubble Space Telescope image of Typhon and its moon Echidna, taken in 2006
Discovery
Discovered byNEAT
Discovery date5 February 2002
Designations
(42355) Typhon
Pronunciation/ˈtfɒn/
Named after
Τυφών Typhōn
2002 CR46
SDO
Centaur
AdjectivesTyphonian /tˈfniən/
Symbol (rare)
Orbital characteristics
Epoch 13 January 2016 (JD 2457400.5)
Uncertainty parameter 2
Observation arc9563 days (26.18 yr)
Aphelion58.982252 AU (8.8236193 Tm)
Perihelion17.545721 AU (2.6248025 Tm)
38.263987 AU (5.7242110 Tm)
Eccentricity0.5414560
236.70 yr (86453.7 d)
14.61898075°
0° 0m 14.991s / day
Inclination2.4252078°
351.9098598°
159.3215723°
Known satellites1 (Echidna)
TJupiter4.692
Physical characteristics
138±9 km
162±7 km
Mass≈9.082×1017 kg
Mean density
0.66+0.09
−0.08
 g/cm3
9.67 h (0.403 d)
0.044±0.003
0.10±0.02
B−V=0.74±0.02 V−R=0.52±0.01
7.5

    42355 Typhon (/ˈtfɒn/; provisional designation 2002 CR46) is a scattered disc object that was discovered on February 5, 2002, by the NEAT program. It measures 162±7 km in diameter, and is named after Typhon, a monster in Greek mythology.

    Typhon is the first known binary centaur, using an extended definition of a centaur as an object on a non-resonant (unstable) orbit with the perihelion inside the orbit of Neptune.

    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 () has been used, which might be identified with U+1F300 🌀 CYCLONE (U+FE0E VARIATION SELECTOR-15 is used to make the character display as text).