Goethe University Frankfurt am Main Tamara Koch, Robin Nowok, Yannik - - PowerPoint PPT Presentation

• 10. August 2017

Goethe University Frankfurt am Main Tamara Koch, Robin Nowok, Yannik Schaper

exciss@stud.uni-frankfurt.de

Überflieger Wettbewerb 2017

• 10. August 2017

EXCISS Team

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• Y. Schaper (Physics)
• O. Christ (Mineralogy)
• M. Lindner (Geoscience)
• F. Schmuck (Geoscience)

P.-T. Genzel (Mineralogy)

• S. Rempt (Mineralogy)
• Y. Matschey (Geoscience)
• D. Mederos Leber (Physics)
• R. Nowok (Mineralogy)
• A. Beck (Geochemistry)
• T. Koch (NanoGeoscience)

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Introduction

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Chondrules

• One of the oldest materials in our solar system
• Building blocks for the planetary system

How did the first solid particles of our solar system form?

• Is the answer in the chondrules?

Kerr, Science (2013)

“(…) meteoritics who know chondrules must collaborate with astrophysicists who know what it was like at the beginning of our solar system.”

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What are Chondrules?

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• ldest material in
• ur solar system

Ø mm-sized spherical objects consist of silicates and metal crystallized from a melt (> 2000 K) building blocks for the planetary system

Summarized in Zanda, Earth & Planetary Science Letters (2004) Video: NASA's Goddard Space Flight Center Conceptual Image Lab

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“We all know how chondrules are formed – by chondrule formation processes”

Alan Rubin

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Chondrule Formation Processes

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Impact Plumes Impact Jetting FU Orionis

Hot Inner Nebula

Bipolar Flows Nebular Lightning Magnetic Flares Accretion Shocks Nebular Shocks

Brandon et al., Nature (2017); Marrocchi et al., Science (2016); Johnson et al., Nature (2014); Kerr, Science (2013); Alexander et al., Science (2008); Cuzzi et al., Nature (2006); Desch, Nature (2006); Summary in Boss, Chondrules and the Protoplanetary Disk 1996

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Nebular Lightning Theory

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Fundamentals

• Electrical charging by grain-grain collisions in the nebula
• Rapidly discharge through lightning bolts

Arguments against:

• Unclear if charge separation is possible
• Insufficient energy to melt mm-sized aggregates
• Cooling rate is too fast to form chondrule textures

Whipple, Science (1966); Desch & Cuzzi, Icarus (2000); Desch & Connolly, Icarus (2002)

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Nebular Lightning Theory

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Fundamentals

• Electrical charging by grain-grain collisions in the nebula
• Rapidly discharge through lightning bolts

Arguments for:

• Fast enough for rapid heating
• Different chondrule properties are possible
• Repeating heating events

Whipple, Science (1966); Desch & Cuzzi, Icarus (2000); Desch & Connolly, Icarus (2002)

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Chondrule Formation Experiments

• 1 mm dust aggregates as starting material
• Tmax = 6500 K, electrical charging = 7 – 14 kV
• Most of the aggregates were destroyed

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Güttler et al., Icarus (2008)

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Experiments in Micro-Gravity

• No chondrule formation

experiments in micro-gravity

• Processes after chondrule formation
• Collision dynamics of dust

coated chondrules

• ZARM Drop tower in Bremen

(7 s micro-gravity) Too short for chondrule formation!

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Beitz et. al, Icarus (2012)

5 mm

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Experiments in Micro-Gravity

• NanoRocks in

Nanorack cube

• Low energy collisions of

mm-sized particles

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Brisset et al., EPSC abstract (2015)

1 cm

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EXCISS – Idea

• Chondrule formation

experiment under long-term micro-gravity conditions

• Heating events by electrical

discharges (Nebular lightning) Experimental concept

Modified from Scott, Chondrules and the Protoplanetary Disk (2007)

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EXCISS – Idea

• Combination of heating

and collision experiment

• Collisions of molten and

unmolten particles

• Several heating events

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Advantages of long-term micro gravity

Modified from Scott, Chondrules and the Protoplanetary Disk (2007)

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Experimental Set-up

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EXCISS – Sample Chamber

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• Pt electrodes, d = 3 mm
• 0.005 g of Mg2SiO4

(olivine)

• Particle size = 100 µm
• p = 250 Pa,

Ne atmosphere

• Ubreakdown = 500 V

Properties

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1:1 model

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EXCISS – Circuit Diagram

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sample chamber

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Event Timeline at ISS

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10 min 50 min

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Data Analysis

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Camera Data

• Particle velocities

(absolute/relative)

• Collisions of molten and

solid particles

• Formation and growth of

aggregates Sample

• Size and shape
• Microstructure
• Mineralogical and

chemical properties

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Sample Analysis

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TEM Philips CM 200 SEM Jeol JSM-6490 Renishaw Raman spectrometry

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Implementation Schedule

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Sample Synthesis

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Possible Scenarios Solution Approach vibrations destroy electrical contacts tests on vibrating table data transfer save data on mass storage unexpected power loss additional batteries for raspberry particles precipitate at electrodes and sample chamber walls tiny vibrating motor at the sample chamber, IR coating

Risk Mitigation

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Outreach Projects

Frankfurter Allgemeine Zeitung, 04.04.2017

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Outreach Projects

• Social Media, Newspaper
• Design cooperation with

August-Bebel-Schule for media design

• Scientific paper
• Scientific conferences

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Conclusion

• Chondrule formation experiment in long-term micro-

gravity: combines melting and aggregation induced by electrical discharges

• A straight forward experiment will present crucial new

results to the origin of our solar system

• EXCISS, the first chondrule formation experiment at the

ISS? – definitely not the last!

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This experiment is only possible in micro-gravity!

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Acknowledgement

Unconditional support from the institute of geoscience at the Goethe University

• Prof. Frank E. Brenker
• Prof. B. Winkler
• M. Röder
• D. Merges

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Thank you for your attention!

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