Astrobiology 740 Stardust Highlights from LPSC March 17, 2006 Dr. Karen J. Meech, Astronomer Institute for Astronomy, Univ. Hawaii [email protected]@ifa.hawaii.edu;

Astrobiology 740Astrobiology 740Stardust Highlights from LPSCStardust Highlights from LPSC

March 17, 2006March 17, 2006

Dr. Karen J. Meech, AstronomerDr. Karen J. Meech, Astronomer

Institute for Astronomy, Univ. HawaiiInstitute for Astronomy, Univ. Hawaii

[email protected]@ifa.hawaii.edu; (808) 956-6828; (808) 956-6828

Return To EarthReturn To Earth

Jan 15, 2006Jan 15, 2006 Image from DC-8 flying N Image from DC-8 flying N

of the Nevada drop siteof the Nevada drop site Soft landing at 3:10am Soft landing at 3:10am

MSTMST Landed in mud, not waterLanded in mud, not water Some of the ablation Some of the ablation

material came off at material came off at impact, leaving a “clean” impact, leaving a “clean” capsulecapsule

Capsule was intactCapsule was intact

Sample Sample RecoveryRecovery

Only Comet samples looked at, no ISM samplesOnly Comet samples looked at, no ISM samples Each compartment is removed (surrounded by a thin foil)Each compartment is removed (surrounded by a thin foil) Aerogel is cut into wedges for particle extractionAerogel is cut into wedges for particle extraction Particles visible to the naked eyeParticles visible to the naked eye Cratering analysis of the very small dust in the foilsCratering analysis of the very small dust in the foils

Analysis goes through 7/15/06Analysis goes through 7/15/06

Mineralogy & PetrologyMineralogy & Petrology Crystalline amorphous silicates are Crystalline amorphous silicates are

abundantabundant Some very large particles ~40 mmSome very large particles ~40 mm Many grains are chondritic in Many grains are chondritic in

composition for most elementscomposition for most elements C is heterogeneously distributed in C is heterogeneously distributed in

particlesparticles Particles are very primitive Particles are very primitive

compared to IDPs compared to IDPs Large 1-10 micron grains of Large 1-10 micron grains of

forsterite, enstatite, pyrrhotite, and forsterite, enstatite, pyrrhotite, and perhaps CaI like minerals are perhaps CaI like minerals are commoncommon

ChemistryChemistry

Above: forsterite Above: forsterite graingrain Layer of melted Layer of melted

aerogel on outside aerogel on outside with NiFeS grainswith NiFeS grains

CaO > 0.5 wt %CaO > 0.5 wt % FeO < 1 wt %FeO < 1 wt % High Cr, low Fe High Cr, low Fe

olivinesolivines

Possible contaminantsPossible contaminants Many control studiesMany control studies Aerogel ahs aromatic & aliphatic Aerogel ahs aromatic & aliphatic

functional groupsfunctional groups C is heterogeneously C is heterogeneously

distributed in grainsdistributed in grains Weak organic signalsWeak organic signals

Organics rich in oxygen (alco-Organics rich in oxygen (alco-hols and ethers) and N (amines hols and ethers) and N (amines and pyrols) – similar to IDPsand pyrols) – similar to IDPs

Isotopic signatures (raman)Isotopic signatures (raman) Higher D/H, Higher D/H, 1515N/N/1414N: N: D = 850 D = 850

+/- 340 per mil+/- 340 per mil No evidence of carbonates or No evidence of carbonates or

clay mineralsclay minerals

Impact CratersImpact Craters

Seen in the Al foilsSeen in the Al foils Many crater 0.5-1.0 Many crater 0.5-1.0 m acrossm across Cumulative size distributionCumulative size distribution

Slope see in Al shallower than the dust flux monitor Slope see in Al shallower than the dust flux monitor from flybyfrom flyby

Mass index of 0.2 vs. 0.7 for DFMMass index of 0.2 vs. 0.7 for DFM ConclusionsConclusions

~ 200 particles > 10 ~ 200 particles > 10 mm Craters show aggregates of particlesCraters show aggregates of particles Impact residues have a variety of compositionsImpact residues have a variety of compositions

ConclusionsConclusions

Crystalline & amorphous silicates are Crystalline & amorphous silicates are abundant: uncertain how much is abundant: uncertain how much is preserved from ISMpreserved from ISM

Many high temperature minerals are seenMany high temperature minerals are seenClearly the cometary material has seen Clearly the cometary material has seen

high Temperatureshigh TemperaturesHot regions of solar nebula?Hot regions of solar nebula?X-wind heating in the disk?X-wind heating in the disk?

Documents

Astrobiology 740 Stardust Highlights from LPSC March 17, 2006 Dr. Karen J. Meech, Astronomer Institute for Astronomy, Univ. Hawaii [email protected]@ifa.hawaii.edu;