AS 101: COMETS LECTURE
The icy bits of chapter 12:
What are cometary orbit like?
What are comets like?
What should I call Pluto?
• Comets visible with long tails are only a small fraction of the solar system’s
population of comets.
o Occasionally passes through the inner solar system
o Ice composition
• Long orbital comets:
o 1000s to millions of years
o Can reach 50,000 AU form the sun
o Orbits can have any inclination
o Doesn’t orbit sun in same direction as planets
• Short Orbital Periods:
o Less than 200 years
o Travel around the sun in same plane and direction as the planets
o Go no further from the sun than 2 Neptune’s distance
o Why do they enter the inner solar system at all?
o Oort Cloud – Don’t really know anything about it
o Do they always have tails?
o Why do comets have tails?
o Does the direction of the tail tell us where the comet is going?
• What makes up a comet:
o Solid nucleus (permanent)
o Coma of gas (temporary)
o Two tails (temporary)
o Violent jets of gas and dust
o Tail o