Comets Easy to find, but only if you know what to look for - Dark location Patience Methodical Careful If you think you’ve 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)

If it passes all these tests, then send it in to the IAU Central Bureau for confirmation. your name your address and contact details ( 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, you’ll become Immortal!

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 < 200 years C/ - comet with period > 200 years D/ - comet that disappeared A/ - oops, an asteroid

Year of discovery, followed by 1/2 month of discovery code and order of discovery January = A, BJuly=N,O February = C, DAugust=P,Q March = E, FSeptember=R,S April = G, HOctober=T,U May = J,KNovember=V,W June=L,MDecember=X,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

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

Comet brightness estimate V = H n log (r) + 5 log  V=integrated 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.)  = Earth-comet distance (A.U)

Orbital elements for comets – for orbit prediction/tracking e = eccentricity (0-1)i = inclination (degrees) T = date of Perihelionq = perihelion distance (AU)  = longitude of the ascending node (degrees)  = argument of the perihelion (degrees)

Why study comets? Primordial Two populations Influence of solar winds Source of meteor showers See break-ups Unpredictable – potential impacts They’re just cool

Comet McNaught C/2006 P1

17/P Comet Holmes

Asteroids +160,000 observed +14,500 named

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, NZ, 2008NA 1, 2008NB 1, NZ NA 2, 2008NB 2,

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.

But some vehicles are toughertougher

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

Iron - Nickel Meteorites

Martian Meteorites

Micrometeorites

Collecting micrometeorites Magnets Collecting Dish/Surface Dishes/Containers Snow Use microscope to distinguish micrometeorites from crap