Chiron Comet or Asteroid

1
Chiron Comet or Asteroid?

• Indunil Fernando
• Astronomy 330

2
Basics

• Was discovered in 1977 by Charles Kowal
• Is not to be mistaken with ChAron
• Big controversy about whether its an asteroid or
  comet
• Tail appearing in 1988 indicated that it might be
  a comet
• Derives its name from a mythical Greek Centaur
  interestingly this is because of its duality!

3
A bit more information

• Hangs out between the orbits of Saturn and Uranus
• Has a semi-major axis of around 13.67 AU.
• Perihelion is approximately 8.449 AU, while
  aphelion is about 18.891 AU.

4
Some Physical Characteristics

• Mass 2.4-3.01018 kg
• Density 2.0 g/cm3
• Absolute Magnitude 6.5
• Albedo 0.1
• Mean Surface Temperature 75K
• Rotation Period 0.2466 days, or 5.918 hours

5
Some oddities

• Was given its own classification, with more to
  follow ( like 4015 Wilson-Harrington and 7968
  Elst-Pizarro )
• Belongs to the family of Centaurs
• Because of the Comet/Asteroid duality, which
  co-insides with the Horse/Man duality of a
  Centaur
• Is thought to be an outcast of the Kuiper Belt

6
(No Transcript)
7
Orbit of Chiron
8
Why the Kuiper Belt?

• Its thought that Chiron is a young object, and
  that it has to have come from our solar system
• Its thought that gravitational perturbations by
  the gassy giants routinely spew out some bodies
  from the kuiper belt.
• Simulations and calculations have shown that
  objects the size of Chiron are especially the
  type who get thrown off the belt.

9
More reasons

• The main reason behind why astronomers think
  Chiron is from the Kuiper belt is
• Because its only been in orbit for a small
  amount of time.
• This is because Chirons orbit seems to be
  unstable, and at the rate its been observed to
  be losing mass, it should completely vaporize in
  a few million years
• It hasnt vaporized yet, so it should be young,
  so the obvious source for it to come from is the
  KB.

10
A bit more on the Asteroid/Comet debate

• Its size fits within the range of asteroids that
  might have been pushed off. But it has been
  observed to have a tail
• And a coma, which at times has been measured to
  be almost 2 million km in diameter
• The coma is thought to have Carbon monoxide, and
  methane, as well as molecular nitrogen.

11
Current Research

• Current research is being conducted by the Chiron
  Perihelion Campaign of NASA.