A Star in the Lab

There is nothing better than analyzing a sample in the lab if you want to get accurate and comprehensive results. Despite stars being lightyears away it’s possible to get a star (a tiny piece of it to be precise) into our labs in a relative easy way.

The solar system started life as a cloud of gas and dust produced by previous stars. Most of this material underwent some homogenization resulting in a very well mixed starting material but some of those little dust grains survived. They can be found in very primitive meteorites which haven’t undergone any alteration.

These stellar dust grains are usually smaller than a thousandth of a millimetre and have abundances in primitive meteorites of only a few parts per million. They can be recognized by their ‘strange’ isotopic abundances which are the result of stellar nucleosynthesis. Measuring these isotope ratios it’s possible to determine the type of star the grain came from and more importantly test stellar models which should produce just the same material as they simulate a stars life.

Presolar SiC Grain

An SEM-image of a silicon carbide presolar grain which was extracted from the Murchison meteorite.

We are analyzing these so-called presolar grains here in our labs mainly with our TOFSIMS instruments but also using RELAX to analyze the Xenon in individual grains. The TOFSIMS measurements give a comprehensive picture of the grain by measuring as many elements as possible and even getting close to get a 3D-picture of it. Although there are limits to this due to the size of the grains and the lateral resolution of our instruments.

Our findings show that at least some of the grains have matter implanted in their outer layer which probably happened in a shockwave from a supernova explosion. We have also started to extract these grains using a gentle, freeze-thaw method because the standard technique which uses acids to dissolve the rest of the meteorite has an effect on the outer layers of the grain altering it’s composition.

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About Torsten Henkel

I'm a research assistant at the University of Manchester studying mainly presolar grains but also comets and solar wind. I have been heavily involved in building two time-of-flight secondary ion mass spectrometers in our labs which is my main instrument to analyze samples.
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4 Responses to A Star in the Lab

  1. Pingback: How small is small? | Earth & Solar System

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  4. Pingback: C and N isotopes in presolar grains and stars | Earth & Solar System

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