Small Bodies & the Origin of the Solar System1

Unused Spare PartsComets, asteroids, and meteors are the unused leftovers from the formation of the solar system.

Their chemical compositions and distribution yield clues as to how the solar system formed.2

Asteroids rocky leftovers of the inner solar systemLocationAsteroid BeltTrojan or Lagrange AsteroidsRandom OrbitsTypes of AsteroidsMinor planetsNEOs3

Asteroid beltGenerally, just outside Mars orbit2.7 A.U. average distanceTotal mass of all asteroids is

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Lagrange AsteroidsClusters of asteroids co-orbit with the gas giant planets, 60o ahead and 60o behind the positions of the planets.

The clusters are centered on the L4 and L5 Lagrange points (points in space where Jupiters gravitational influence equals the suns gravitation.)

Jupiters Lagrange asteroids are known as the Trojan asteroids.6

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Types of AsteroidsS Stony

C Carbonaceous (modified stony asteroids with dark surfaces and interiors)

M Metallic (comparatively rare)8

Gaspra a typical stony asteroidStony Asteroids9

Some asteroids are thought to be rubblepiles held together by very low gravity.10

Major Asteroids or Dwarf Planets?Over 200 objects have diameters of >100 km.

Ceres largest, the size of Texas (1030 km). Named after the Roman goddess of the harvest (cereal). Recently named a dwarf planet.11

Rotation of Ceres Best ModelWe dontknow whatthe whitespot is yet.12

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Major AsteroidsVesta smaller (450 km diameter), but much brighter. Barely visible to naked eye.Movie of Vestas rotation.http://atropos.as.arizona.edu/aiz/teaching/nats102/images/Vesta.mpgPallasJuno

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Vesta shows signs of having been moltenat one point in its history.15

NEOs (Near Earth Objects)and PHAs (Potentially Hazardous Asteroids)Hundreds of asteroids cross earths orbit !

Several have approached within 600,000 km of earth (2 times moons orbital distance)

Collisions with Earth have occurred in the past16

Barringer Crater in Arizona from an impact within the last 50,000 to 100,000 years17

This asteroid has its own little moon !18

Toutatis one of the closest !Toutatis spins on 2 axes.5 km long. Passed just 29 lunar distances from the earth in 2000.19

Mission to AsteroidsDeep Space 1 flew by asteroid 1992 KD Braille in 1999.

N.E.A.R. took close-up photos of, then landed on asteroid Eros, Feb. 12, 2001.

JAXA Hayabusa visited asteroid Itokawa in 2005. It had a small lander which should have landed on the asteroid, but malfunctioned.20

Asteroid 433 Eros21

NEAR landing on Eros.22

Hayabusa - ion propulsion - autonomous navigation - sample return23

Comets outer S.S. messengersStructureOrbits & TypesOort Cloud vs. Kuiper BeltFamous CometsWhat message do they convey?24

StructureNucleusWater ice, frozen CO2, N2, methane, ammonia, HCN, (CN)2 (cyanogen), amino acids, sugars all detected.Embedded with rocks and dustExtremely dark, tarry surface.ComaEnvelope of water vapor and H2 around nucleus25

Structure (2)Ion tail ionized gas pushed directly away from the sun by solar wind.

Dust tail heavier particles that follow along behind the path of the comet.The dusty path of a comet lingers for decades, even centuries. When the earth passes through the dusty path again later, a meteor shower is produced.26

StructureDirty Snowballs27

Sunlight causesjets of gas tospew fromthe cometsnucleus. Thiscreates thecoma.Jets of gasDark, tarry organic coatingPhoto by Giotto spacecraft (ESA)Nucleus of Halleys Comet28

Nucleus of Borrelly29

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Ion or plasma tailDust tailDirection of comets movement32

Comet Origins & OrbitsKuiper BeltShort period comets (return

Comet Origins & Orbits (2)Oort CloudLong period comets (return >200 years or may only pass by sun once)Spherical shell of matter up to 2 light years (65,000 A.U.) in radius.Trillions of cometsComets may come in from any direction, with prograde or retrograde orbits.34

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Famous CometsHalley (1984)

Hale Bopp (96)

Hyakutake (94)Shoemaker-Levy 9 (94)

Kohoutek (75)

West (75)36

Halleys comet198637

Halleys Comet OrbitMany comets have retrograde orbits38

Comet Shoemaker-Levy 9 broke into aseries of fragments before impactingJupiter.The fireballfrom eachimpact waslarger thanthe earth.39

An atmospheric scar left by the impactof Shoemaker-Levy 9. These faded afterseveral weeks.40

Comet Hale Bopp, 200241

CometSwanhas beenvisiblein oursky thepast fewweeks.42

Past Missions to CometsThere have been 11 past missions to comets, with 2 current missions.

Giotto examined Halleys comet in 1986. Photographed the nucleus from a distance of only 200 km, then continued on to comet Grigg-Skellerup in 1992.43

Past Missions to Comets (2)Deep Impact launched a 350 kg copper impactor into the nucleus of comet 9P/Tempel 1, in July, 2005.A 100 m x 25 m crater was created.

Visible and infrared spectrometers on the parent craft looked for the composition of the nucleus.250,000 kg of water vapor were detected.44

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Current Missions to CometsStardust sampled the coma of P Wild 2 from a distance of 236 km above the nucleus.

Returned comet particles back to the earth for microscopic examination and chemical testing.You can help with the microscopic work bysigning up at the following website.http://stardust.jpl.nasa.gov/home/index.html48

Stardust inside comet Wilds coma.49

Comet particlestrapped in theaerogel (a lightsilicon gel).50

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Current Missions to Comets (2)Rosetta launched 2004 to comet 67P/Churyumov-Gerasimenko. Rosetta will fly along with the comet for 2 years as it approaches the sun, beginning in 2014. It also has a small lander which will explore the comets nucleus.

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Formation of the solar systemAccretion from a nebula of gas and dust.Spinning nebula flattens to a diskDifferent materials condense at different distances from the sun (temperature gradient).Other solar systems may be quite different from ours.53

A rotating cloud of gas & dust 54

Rotation causes the nebula to flatten55

A star ignites in the center and a temperature gradient forms.56

Solids condense close to the starVolatiles & ices condense farther out57

Were unsure of our modelSolar systems that weve observed around other stars are quite different from ours.Planets Jupiter-sized and larger have been observed orbiting at Mercury-like distances from their stars.Do gas giants form closer to the star and then migrate outward, or vice versa?58

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http://www.newscientist.com/data/images/ns/cms/dn8259/dn8259-3_506.jpghttp://www.fli-cam.com/images/comet-liner.jpghttp://www.nasa.gov/images/content/116911main_spitzer-comet-060205-browse.jpghttp://galileo.rice.edu/images/things/comet_1532_apian-l.gifhttp://www.astrocentral.co.uk/comet_diagram.gifhttp://www.solarviews.com/thumb/comet/comet.gifhttp://physics.uoregon.edu/~jimbrau/BrauImNew/Chap14/FG14_06.jpghttp://www.mallorcaweb.net/masm/Aster/astervarios.JPGhttp://en.wikipedia.org/wiki/Image:Ceres_Rotation.jpghttp://near.jhuapl.edu/http://www.isas.jaxa.jp/e/enterp/missions/hayabusa/index.shtmlhttp://www.daviddarling.info/encyclopedia/N/NEAR.htmlhttp://www.nasa.gov/worldbook/comet_worldbook.htmlhttp://herschel.jpl.nasa.gov/images/kuiper_oort.jpghttp://www2.jpl.nasa.gov/sl9/gif/sl9hst.gifhttp://bluepoint.gen.tr/sagan/sholevy9.gifhttp://nssdc.gsfc.nasa.gov/planetary/sl9/image/sl9g_hst5.gifhttp://www.magma.ca/http://www.spaceweather.com/swpod2006/25oct06/lawrence.jpghttp://solarsystem.nasa.gov/missions/profile.cfmhttp://www.hour25online.com/pix/comet-tempel1-orbit_01a.jpghttp://www.cfa.harvard.edu/press/Deep-Impact_lores.jpg60

http://deepimpact.jpl.nasa.gov/gallery/jpg/HRI_937_1.jpghttp://stardust.jpl.nasa.gov/images/gallery/Wild2Encounter2.jpghttp://stardust.jpl.nasa.gov/images/gallery/aerogel_tracks.jpghttp://stardust.jpl.nasa.gov/images/gallery/aerogelhand.jpghttp://boojum.as.arizona.edu/~jill/NS102_2006/Lectures/Lecture6/09-13.jpg

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Meteoroids asteroids on a collision coursewith us!Meteor the trail of light & ionized gas left by a meteoroidMeteorite whats left of a meteoroid that hits the Earth.Bolide a fireball or especially bright meteor.

Types of MeteoritesTypes just like asteroids! stony (incl. carbonaceous chondrites) irons & iron / nickel (90% / 10%) stony-irons (a combination of materials) the type of meteorite tells you where it came from.

A stony meteorite (hard to find)

An iron meteorite (easier to find)

A carbonaceous chondrite

Meteoroids were formed in parent bodies (planetessimals)Stonies were formed in the:mantleIrons were formed in the:core

Meteoroids early planet stuffMeteoroids come from the earliest condensed stuff in the solar system. They give us the chemical composition of the earliest planetissimals.Most are about 4.6+ billion years old.

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