Bit of Administration …. Washburn ObservatoryWashburn Observatory –Thursday, 8:30 - 9:30 PortfoliosPortfolios –Due Thursday, April 29, because of possible

Bit of Administration ….Bit of Administration ….• Washburn ObservatoryWashburn Observatory

– Thursday, 8:30 - 9:30Thursday, 8:30 - 9:30

• PortfoliosPortfolios– Due Due Thursday, April 29Thursday, April 29, because of possible TAA strike, because of possible TAA strike

• Put in box outside 6522 SterlingPut in box outside 6522 Sterling

– All 5 must be All 5 must be securelysecurely bound together, including ones already graded bound together, including ones already graded– Late portfolios will lose creditLate portfolios will lose credit

• Lab 3Lab 3– Due Due Thursday, April 29Thursday, April 29, because of possible TAA strike , because of possible TAA strike

• Put in box outside 6522 SterlingPut in box outside 6522 Sterling

– Problem 5, HW 1 is a good starting point for the lab questionsProblem 5, HW 1 is a good starting point for the lab questions– Note typo in Question 3 - “Jupiter” => “Saturn”Note typo in Question 3 - “Jupiter” => “Saturn”

THE EXTRA-SOLAR PLANET PROJECT • Phase 1: Last week’s quiz.

• Phase 2 : A Web-Lecture on Extra-Solar Planets.– Learn about extra-solar planets and have opportunity to earn 5 pts extra credit.

• 2 pts for evaluation questions• 3 pts for success on quiz

– Preparation for next week’s discussion sections (5/3-5/7).– Access: http://eteach.engr.wisc.edu/meibom/espp/index.html– Speed: 300 Kbps, 100 Kbps, and 37 Kbps.

• The hardware requirements for viewing the lecture are:– A computer with connection to the Internet.– Computer speakers or headphones.

• The software requirements for viewing the lecture are:– Windows Operating System.– Internet Explorer version 5.5 or later.– Power Point 2002 or later ("Power Point Animation plug-in").

• Campus computer-labs:– http://www.doit.wisc.edu/computerlabs/index.asp– Bring headphones!

http://www.astro.wisc.edu/astro104

http://www.astro.wisc.edu/astro104

Asteroids, Comets, Meteors, and PlutoAsteroids, Comets, Meteors, and Pluto



• AsteroidsAsteroids



QuickTime™ and aCinepak decompressorare needed to see this picture.

Asteroids, Comets, Meteors, and PlutoAsteroids, Comets, Meteors, and Pluto• AsteroidsAsteroids

• 150,000 catalogued150,000 catalogued as many as “grains of sand on the beach”as many as “grains of sand on the beach”• Size - few km typical, 1000 km largest (half Pluto)Size - few km typical, 1000 km largest (half Pluto)


• Density - 2 - 3 gm/cmDensity - 2 - 3 gm/cm33

• Note: Note: About as expected for rock in low gravityAbout as expected for rock in low gravity• Shape - Irregular because of low mass => low gravityShape - Irregular because of low mass => low gravity


• 150,000 catalogued, as many as grains of sand on the beach150,000 catalogued, as many as grains of sand on the beach• Size - few km typical, 1000 km largest (half Pluto)Size - few km typical, 1000 km largest (half Pluto)


• AsteroidsAsteroids• OrbitsOrbits


• AsteroidsAsteroids• Orbits - Earth-Crossing AsteroidsOrbits - Earth-Crossing Asteroids


• CometsComets


Ices and RockIces and RockIcy PlanetesimalIcy Planetesimal

10 km

““Nucleus”Nucleus”

• CometsComets

Plasma (Gas) TailPlasma (Gas) Tail

DustDust TailTail

ComaComa


• CometsComets• Orbital PropertiesOrbital Properties

• Long period cometsLong period comets• P ≈ 10P ≈ 1055 - 10 - 1066 yr => A ≈ 10,000 AU yr => A ≈ 10,000 AU• Elliptical to hyperbolic orbitsElliptical to hyperbolic orbits• Come from all directions - “isotropic”Come from all directions - “isotropic”


• Comets - Oort CloudComets - Oort Cloud• Perturbations by passing stars cause comets to fall inPerturbations by passing stars cause comets to fall in• Origin of long-period cometsOrigin of long-period comets

1 trillion comets1 trillion comets


• CometsComets• Orbital PropertiesOrbital Properties

• Long period cometsLong period comets• P ≈ 10P ≈ 1055 - 10 - 1066 yr => A ≈ 10,000 AU yr => A ≈ 10,000 AU• Elliptical to hyperbolic orbitsElliptical to hyperbolic orbits• Come from all directions - “isotropic”Come from all directions - “isotropic”

• Short period comets Short period comets •P < 200 yr => A < 50 AUP < 200 yr => A < 50 AU• Highly ellipticalHighly elliptical• In ecliptic planeIn ecliptic plane


•Kuiper Belt ObjectsKuiper Belt Objects





SednaSedna

Pluto and CharonPluto and Charon

TritonTriton

650 KBOs discovered650 KBOs discovered100,000 with radii > 10 km100,000 with radii > 10 km


•Comets - Evolutionary PictureComets - Evolutionary Picture

Primordial Icy PlanetesimalsPrimordial Icy Planetesimals

Fragmented Icy Planetesimals (KBOs)Fragmented Icy Planetesimals (KBOs)

Rocky PlanetesimalsRocky Planetesimals

Icy PlanetesimalsIcy Planetesimals

Jupiter FormsJupiter Forms

Oort CloudOort Cloud

Kuiper BeltKuiper Belt


• CometsComets• Periodic Comets - e.g., Halley’s CometPeriodic Comets - e.g., Halley’s Comet

• Highly ellipticalHighly elliptical• P < 200 yrP < 200 yr• Put into short periods by JupiterPut into short periods by Jupiter


• CometsComets• Periodic Comets - e.g., Halley’s CometPeriodic Comets - e.g., Halley’s Comet

• Highly ellipticalHighly elliptical• P < 200 yrP < 200 yr• Put into short periods by JupiterPut into short periods by Jupiter• Fragmented after many passages around SunFragmented after many passages around Sun


• MeteorsMeteors• Showers - debris of old cometsShowers - debris of old comets

Earth orbitEarth orbit

Past CometPast Comet


• MeteorsMeteors• Types - Processed MeteoritesTypes - Processed Meteorites

• Stony MeteoritesStony Meteorites• 93%93%• Just like crust of EarthJust like crust of Earth

• Iron MeteoritesIron Meteorites• 6 %6 %• Crystallization patterns => long cooling timesCrystallization patterns => long cooling times


• MeteorsMeteors• Types - Primitive MeteoritesTypes - Primitive Meteorites

• Stony, with trace of pure metallic flakesStony, with trace of pure metallic flakes• Carbonaceous chondritesCarbonaceous chondrites

• Carbon compounds, and even waterCarbon compounds, and even water


• SummarySummary• AsteroidsAsteroids

• Rocky PlanetesimalsRocky Planetesimals• CometsComets

• Long - Period = Icy PlanetesimalsLong - Period = Icy Planetesimals• Short - Period = Fragmented KBOsShort - Period = Fragmented KBOs

• Pluto, Sedna, Triton, Kuiper Belt ObjectsPluto, Sedna, Triton, Kuiper Belt Objects• Icy PlanetesimalsIcy Planetesimals

• MeteorsMeteors• Primitive Meteors = Rocky PlanetesimalsPrimitive Meteors = Rocky Planetesimals• Processed Iron and Stony MeteoritesProcessed Iron and Stony Meteorites Fragmented asteroidsFragmented asteroids• Meteor ShowersMeteor Showers Fragmented cometsFragmented comets


Documents

Bit of Administration …. Washburn ObservatoryWashburn Observatory –Thursday, 8:30 - 9:30 PortfoliosPortfolios –Due Thursday, April 29, because of possible