sep 162012
 

 

A team of researchers from the Institute of Space Astrophysics (IAS / CNRS-Université Paris Sud) examining the meteorite “Paris”,  was able to highlight the presence of organic components similar to those of the interstellar medium.

Fig.2: This photograph shows the Paris meteorite fusion crust (croute de fusion) formed during atmospheric entry partially oxidized (orange) traces (traces d’oxydation) and the interior well preserved meteorite (visible in the center) where you can see small white inclusions called chondrules (chondre). Image Credit: MNHN

The meteorite “Paris” is a carbonaceous chondrite 1 CM type 2 with two lithologies of which one is affected more than the other. This 1.2 kg meteorite was recently acquired by the Laboratory of Mineralogy and Cosmochemistry (LMCM / MNHN-CNRS).

Although the circumstances of the fall of “Paris” are unknown, it appears to have been remarkably preserved in the terrestrial environment and in particular as regards to its original organic matter. Indeed, organic materials similar to those observed in the interstellar medium have been highlighted.

Ten mg were provided by B. Zanda from the MNHN. Some samples of fifty microns were collected and analyzed by the SMIS (Microscopy and Spectroscopy in the Infrared using Synchrotron) of  Synchrotron SOLEIL (CNRS-CEA) which, due to its high brightness coupled with a spatial resolution that can go up to 6 microns, allowed us to detect small inclusions rich in organic matter with spectroscopic signatures in the infrared absolutely similar to those observed in some molecular clouds in the interstellar medium.

Fig.2: Comparison of IR spectra of a fragment of Paris (frag2) than GCS3 sources and SgrA * in the region 3.4μm (upper panel) and the region around 6 microns (lower panel in which the arrows indicate common bands in the spectrum of Paris and in the interstellar medium). Image Credit: CNRS


Figure 2 compares the infrared signatures of a fragment of  “Paris” (named frag2) with those of two infrared sources — protostellar objects that form stars and planetary systems — in the direction of the galactic center, SgrA*, obtained by the Short Wavelength Spectrometer (SWS) satellite ISO (Infrared Space Observatory) in the region of 3.4 microns (top figure) and in the region of around 6 microns (bottom figure).

This new discovery allows reopening the debate on primitive chemicals in certain meteorites and the role of chemical processes in molecular clouds, needed for the production of large quantities of organic material from abiotic origins and the transition into the prebiotic chemistry in the Solar System objects such as the Earth.

Notes:

  1. Carbonaceous chondrites are a class of primitive meteorites from a parent body undifferentiated. They contain chondrules submillimeter particles are generally spherical in microgravity formed by crystallization of silicate melts at their condensation.
  2. Carbonaceous chondrites are classified according to their carbon and water.

Source: Centre National de la Recherche Scientifique (CNRS)

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