Astrobiology 740 Stardust Highlights from LPSC March 17, 2006 Dr. Karen J. Meech, Astronomer Institute for Astronomy, Univ. Hawaii (808)

Return To Earth Jan 15, 2006 Jan 15, 2006 Image from DC-8 flying N of the Nevada drop site Image from DC-8 flying N of the Nevada drop site Soft landing at 3:10am MST Soft landing at 3:10am MST Landed in mud, not water Some of the ablation material came off at impact, leaving a “clean” capsule Capsule was intact

Sample Recovery Only Comet samples looked at, no ISM samples Only Comet samples looked at, no ISM samples Each compartment is removed (surrounded by a thin foil) Aerogel is cut into wedges for particle extraction Particles visible to the naked eye Cratering analysis of the very small dust in the foils Analysis goes through 7/15/06 Analysis goes through 7/15/06

Mineralogy & Petrology Crystalline amorphous silicates are abundant Crystalline amorphous silicates are abundant Some very large particles ~40 mm Some very large particles ~40 mm Many grains are chondritic in composition for most elements Many grains are chondritic in composition for most elements C is heterogeneously distributed in particles C is heterogeneously distributed in particles Particles are very primitive compared to IDPs Particles are very primitive compared to IDPs Large 1-10 micron grains of forsterite, enstatite, pyrrhotite, and perhaps CaI like minerals are common Large 1-10 micron grains of forsterite, enstatite, pyrrhotite, and perhaps CaI like minerals are common

Chemistry Above: forsterite grain Above: forsterite grain Layer of melted aerogel on outside with NiFeS grains CaO > 0.5 wt % FeO < 1 wt % High Cr, low Fe olivines Possible contaminants Possible contaminants Many control studies Many control studies Aerogel ahs aromatic & aliphatic functional groups Aerogel ahs aromatic & aliphatic functional groups C is heterogeneously distributed in grains C is heterogeneously distributed in grains Weak organic signals Weak organic signals Organics rich in oxygen (alco- hols and ethers) and N (amines and pyrols) – similar to IDPs Organics rich in oxygen (alco- hols and ethers) and N (amines and pyrols) – similar to IDPs Isotopic signatures (raman) Isotopic signatures (raman) Higher D/H, 15 N/ 14 N:  D = 850 +/- 340 per mil Higher D/H, 15 N/ 14 N:  D = 850 +/- 340 per mil No evidence of carbonates or clay minerals No evidence of carbonates or clay minerals

Impact Craters Seen in the Al foils Seen in the Al foils Many crater  m across Many crater  m across Cumulative size distribution Cumulative size distribution Slope see in Al shallower than the dust flux monitor from flyby Slope see in Al shallower than the dust flux monitor from flyby Mass index of 0.2 vs. 0.7 for DFM Mass index of 0.2 vs. 0.7 for DFM Conclusions Conclusions ~ 200 particles > 10  m ~ 200 particles > 10  m Craters show aggregates of particles Craters show aggregates of particles Impact residues have a variety of compositions Impact residues have a variety of compositions

Conclusions Crystalline & amorphous silicates are abundant: uncertain how much is preserved from ISM Crystalline & amorphous silicates are abundant: uncertain how much is preserved from ISM Many high temperature minerals are seen Many high temperature minerals are seen Clearly the cometary material has seen high Temperatures Clearly the cometary material has seen high Temperatures Hot regions of solar nebula? Hot regions of solar nebula? X-wind heating in the disk? X-wind heating in the disk?