Comets

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• Comets
• Easy to find, but only if you know what to look
  for -
• Dark location
• Patience
• Methodical
• Careful

If you think youve found a comet, you should
first Check a good atlas (galaxy, nebula,
etc.) Check list of currently visible or other
newly discovered comets (Websites) Check it
out again the next evening - note any motion
(position change)
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• If it passes all these tests, then send it in to
  the IAU Central Bureau for confirmation.
• your name
• your address and contact details (e-mail address)
  
• date and UT time of observation
• observation method (e.g., naked eye, visual
  telescopic observation, photographic, or
  telescopic CCD)
• specific details on instrumentation (aperture
  size, f/-ratio, etc.) and exposures (type of film
  or CCD, length of exposure, etc.)
• observation site (name of location, giving either
  city/town and state/province/country, or some
  other geographical name nearby) longitude and
  latitude and elevation above sea level can be
  useful
• If all goes well and they confirm it, youll
  become Immortal!

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Comet names Still use the old discoverer naming
system - but when too many are discovered by the
same person (or project), this is too
confusing First part of the name P/ - comet with
period lt 200 years C/ - comet with period gt 200
years D/ - comet that disappeared A/ - oops, an
asteroid
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Year of discovery, followed by 1/2 month of
discovery code and order of discovery January
A, B JulyN,O February C, D AugustP,Q March
E, F SeptemberR,S April G, H OctoberT,U May
J,K NovemberV,W JuneL,M DecemberX,Y On
occasion some look asteroidal, and get a bit of
an asteroid name added in. C/2001 HT50
(LINEAR-NEAT) C/2001 Q4 (NEAT) C/2002 O7
(LINEAR) C/2002 T7 (LINEAR) 2P/Encke
29P/Schwassmann-Wachmann 1 43P/Wolf-Harrington
65P/Gunn 157P/Tritton
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Brightness of a comet How do you measure it? One
method - defocus the telescope/binoculars How
bright should it be? Depends on - Distance from
Sun Distance from Earth Towards/away from the
Sun Size/age of the comet How close to the Sun
in the sky
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Comet brightness estimate V H 2.5 n log (r)
5 log D Vintegrated magnitude H magnitude if 1
A.U. from the Sun, 1 A.U from Earth, also
considered the absolute magnitude n
typically 4 r Sun-comet distance (A.U.) D
Earth-comet distance (A.U)
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Orbital elements for comets for orbit
prediction/tracking e eccentricity (0-1) i
inclination (degrees) T date of Perihelion q
perihelion distance (AU) W longitude of the
ascending node (degrees) w argument of the
perihelion (degrees)
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Why study comets?

• Primordial
• Two populations
• Influence of solar winds
• Source of meteor showers
• See break-ups
• Unpredictable potential impacts
• Theyre just cool

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Comet McNaught C/2006 P1
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17/P Comet Holmes
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Asteroids 160,000 observed 14,500 named
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And how are asteroids named? Old names - Names of
gods, goddesses, people (real) New names - Year,
1/2 Month designation (same as comets) and order
of discovery (also a letter, no I) 2008NA,
2008NB, 2008NC,....2008NZ, 2008NA1,
2008NB1,....2008NZ1 2008NA2, 2008NB2,.............
...
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Why study asteroids? Can determine radius/size
using occultation events - very precise timing,
location dependent. Brightness variations -
composition, rotation, size Asteroids found by
using before-after comparisons of a
region. Asteroids tend to be found in the
ecliptic.
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But some vehicles are tougher
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Meteorites - fragments of comets or
asteroids Most common Stony Macrometeorites -
big ones, look for burned features, crusts,
unusual location, color, metal detectors can
help Micrometeorites - small ones, rain down
continually
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Iron - Nickel Meteorites
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Martian Meteorites
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Micrometeorites
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• Collecting micrometeorites
• Magnets
• Collecting Dish/Surface
• Dishes/Containers
• Snow
• Use microscope to distinguish micrometeorites
  from crap