stardust in laboratory evolution offys sy early solar system · planetary sciences stardust in...

Planetary Sciences

Stardust in Laboratory &&Evolution of Early Solar Systemf y S Sy

Kuljeet K. Marhas13th September 2008

Physical Research Laboratory

K j K

Th

Elements Surrounding Us!

Solar AbundancesCosmic Abundances

=

The interstellar medium is

=Mix from many Stellar Sources

‘ecologically’ speaking a disaster areadisaster area where a large number of

llstellar sources pollute their penvironment with their garbagegarbage

Presolar Grains &Evolution of Early Solar System Kuljeet K. Marhas 13th September 2008


Arrival of the Solar System!We are quite literally stardust!



Picture book of presolar grains!

Graphite grainsSilicon carbide Corundum

500nm500nm

Spinel grainsSilicate grainSilicon Nitride Spinel grainsSilicate grainSilicon Nitride



Work Horse for micron sized particle!SIMS: Secondary Ion Mass Spectrometer



Big Brother!!NanoSIMS: Nano Secondary Ion Mass Spectrometer



Mainstream ~93% Y grains ~1%

Star and Starbits!

Grains are identified as presolar from 1E+4

A+B grains 4-5%Mainstream ~93%

Nova grainsZ grains ~1%Y grains 1%

X grains ~1%

presolar from their completely anomalous 1E+3

1E+4AGBs

C stars

isotopic compositions.

1E+214N

/15N

Solar

The carbon and nitrogen isotopic ratios of presolar

1E+1

olar

ratios of presolar silicon carbide grains span a 1E+0

1E+0 1E+1 1E+2 1E+3 1E+4So Supernovae

huge range. 12C/13C



Stellar Identity!!

SiC Grain

Red Giant



No Pain… No Gain….

Probe wide range of astrophysical processes:g p y p

• Stellar Evolution

• Nucleosynthesis

• Galactic Chemical Evolution

• Stellar dust formation



Arrival of the Solar System!

Molecular CloudCloud

CAI

Proto Sun

CAIs

Solar SystemSolar System



FAQs!

Is it possible to identify the stellar sources contributing to the initial mix ?g

Was it a triggered the collapse?

What was the time scale of collapse ?

What processes and time scales are involved in formation of grains and formation & differentiation of planetesimals and planets?



Calcium AluminumAllende

White Amoeba!

Calcium Aluminum Inclusion

Allende

As seen under aAs seen under a stereo-microscope



Cosmic Clocks!

Now-extinct short-lived nuclides in the Early Solar System serve as cosmic CLOCKS.cosmic CLOCKS.

Solar System ~ 4.5 billion years EXCESS

so any short-lived nuclides with half life <100Ma present in early solar system have become extinct.

If a now-extinct nuclide was incorporated “live” into the first forming solids its fossil records canforming solids, its fossil records can be used to record the time of formation.

24Mg 25Mg 26Mg26Al 27Al



Short-lived Now-extinct Nuclides Present in the Early Solar Systemin the Early Solar System

Radio- Half-life Daughter Reference Nuclide (Ma) Nuclide Nuclide

41Ca 0.10 41K 40Ca26Al 0.74 26Mg 27Al10Be 1.5 10B 9Be60Fe 1.5 60Ni 56Fe53M 3 7 53C 55M53Mn 3.7 53Cr 55Mn107Pd 6.5 107Ag 108Pd182Hf 9 182W 180Hf129I 16 129Xe 127I244Pu 81 Fission Xe 238U146Sm 103 142 Nd 144Sm



No Pain… No Gain….

Probe wide range of early solar system processes:

• Time scale of formation of first solids formation time ofTime scale of formation of first solids, formation time of different planetary objects

• Stellar sourcesStellar sources

• Activity of early Sun



Catching the star-------stardust: Stardust Mission

NASA’s Stardust mission NASA s Stardust mission launched in 1999 to collect dust from comet Wild 2 and return the samples to Earth.

The first ever comet sample return mission.

Science objective: to understand the materials and conditions that went into the f ti f th S l S tformation of the Solar System.



230 km from nucleus

Travel, travail of descent, cross examination!

230 km from nucleusΔV= 6.1 km/s

January 2, 2004



Interstellar dust impacted the

Caught and the catcher : Dust in the Aerogel!

Interstellar dust impacted the aerogel collector grid with a relative speed of about 20 km/s (45,000 mph)

With masses in the picogram regime, the particles should only penetrate about 100 microns into the surface of microns into the surface of the 3cm thick aerogel tiles, leaving behind tracks in the aerogel.

The particles are sub-micron in size and are few in number, approximately 45 in the entire collector.

The collector itself is about 1,000 cm2 in area.



Creeks and cracks!



Standing alone: presolar grain!



spinel, Al-diopside, anorthite, melilite

Unexpected truth: CAI-like particle!

Fe-sulfidesin glass

perovskite void

compressedaerogel“cap”cap



Greenberg modelaggregate of submicron

h i t t ll i

some key questions:some key questions:Match - Mismatch!

amorphous interstellar grains with core-mantle structure

are comets mechanical are comets mechanical agglomerations of agglomerations of unprocessedunprocessed presolarpresolarunprocessed unprocessed presolarpresolar(interstellar) materials? (interstellar) materials? what are the what are the relationships to isotoperelationships to isotope

IDP modelaggregate of submicron grains withrelationships to isotope relationships to isotope

reservoirs in reservoirs in asteroidalasteroidalsamples? to IDPs?samples? to IDPs?do comets provide an do comets provide an

aggregate of submicron grains with few large xtals.chondritic w/ high C, high D/H

ppenhanced reservoir of enhanced reservoir of circumstellarcircumstellar grains with grains with distinct distinct nucleosyntheticnucleosynthetichistories? (i e arehistories? (i e arehistories? (i.e., are histories? (i.e., are grains really “stardust”?)grains really “stardust”?)



Search…Research….Search….. !!!!

there is stardust in STARDUSTbut not primarily isotopically distinctive presolar

grainslimited O isotope analyses of refractory minerals (fo, CAI-minerals) consistent with other similar ( , )primitive solar system materials (CC, IDPs)

Inti isotopically like other CAIs; derives from inner solar system reservoirinner solar system reservoir

implies large scale radial transport in nebulaWild-2 not enhanced reservoir of presolar matter

capture effects severe but not prohibitive



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