Investigating Raman variation across large cluster interplanetary dust particles

Starkey, Natalie A. and Franchi, Ian A. (2011). Investigating Raman variation across large cluster interplanetary dust particles. In: 42nd Lunar and Planetary Science Conference, 7-11 Mar 2011, Houston, TX, USA.



Interplanetary dust particles (IDPs) collected in the stratosphere are dust from comets and asteroids that have arrived in the Earth’s stratosphere via Poynting-Robertson effect after being ejected from their parent body. Chondritic porous IDPs display a range of features indicative of a very primitive nature and are generally believed to originate from comets. While our knowledge is somewhat limited about the internal and near-surface processes affecting non-ice materials within a cometary body, those processes that have occurred will have been different, and probably less pervasive compared to those occurring on the asteroidal meteorite parent bodies.

The abundant organic material present in primitive IDPs may be the result of formation processes that occurred across a large volume of the protoplanetary disk. However, the study of organic material in particles only a few to a few tens of microns across is challenging. Laser Raman microscopy offers a rapid and potentially non-destructive approach for determining some important general characteristics of the organic matter in IDPs. While a number of studies have been conducted to date, the number of IDPs analysed remains relatively small (a few dozen) – particularly when the number of potential parent bodies is considered or the huge volume of the protoplanetary disk that may have contributed to the formation of comets.

Nine IDPs were selected at the Cosmic Dust Laboratory at Johnson Space Center from five large cluster particles on collectors L2005 and L2006. Cluster particles represent large IDPs that broke into smaller pieces on impact with the collector. These particles can be >100 μm across but the individual particles within them are typically 5-15 μm in size. This offers the opportunity to investigate the variability of the Raman signature of the organic matter on a number of scales.

This study is the first part of a larger, on-going project integrating the Raman, mineralogy (ASEM) and isotopic signatures (NanoSIMS) of the particles.

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