2060 Chiron
- Pronounced KAI-ron.
- Chiron orbits between Saturn and Uranus at 13.7 AU.
- It was discovered in 1977 by astronomer Charles T. Kowal.
- Revolution is 51.0 years.
- It is about 250 km in diameter.
- Density is about 0.005.
- Composition possibly of carbonaceous soil over ice.
- No atmosphere.
- 2060 Chiron is a most unique interplanetary body.
- Originally cataloged as an asteroid.
- Initially showed up as a star-like point in early photographs.
- After years of observations, a neutral gray color was established for Chiron.
- Only slight discrepancies in brightness occurred.
- Then it appeared nearly twice as bright as should be in February 1988.
- Over a period of months Chiron became as much as three times it's normal brightness.
- Chiron was slowly orbiting closer to the sun.
- It was determined that Chiron contained ices.
- Its orbital motion toward the sun warmed it.
- Ices began changing into gas.
- Chiron began throwing off a cloud of gas molecules and dust.
- In April 1989, Chiron's status as a comet was confirmed when images showed an expanding coma, or cloud of dust, around Chiron.
- After many months, Chiron's brightness faded.
- Cometary eruptions seemed to have declined.
- Chiron's surface is very dark, soot-blackened ice.
- It would need to be rather large to reflect a substantial amount of light.
- Observations estimated that its diameter is about 180-360 km (110-190 miles).
- A diameter of about 250 km (160 miles) is a likely value.
- Chiron is the largest known comet.
- Because of its size and gravity, dust and gas from eruptions is not blown away into a tail.
- Chiron's gravity grabs hold and keeps it in a cloud about the comet long after each eruption.
- Soon after its discovery, Chiron's orbit was determined to be unstable.
- Every few thousand years, it approaches Saturn.
- It may, in about a million years, pass relatively close to Saturn.
- As a result, it's orbit may then be radically changed.
- Chiron may be thrown out of the solar system.
- Or it might be thrown into the inner solar system.
- At such time, it might then pass by Earth as one of the brighest comets of all time.
- Due to the unstability of its orbit, Chiron must not have been in its present orbit for much of the solar system's 4,500-million-year history.
- In 1992, a second, Chiron-like body was discovered:
- 5145 Pholus was found in an elongated orbit.
- Pholus orbits from just inside Saturn's orbit to just beyond Uranus' orbit.
- This body has the most reddish-brown color observed in a comet.
- These colors suggest an unusual composition.
- Based on sectral analysis, astronomers have suggested that the colors come from organic compounds.
- Whether it displays cometary behavior is yet to be seen.
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