Probing the use of spectroscopy to determine the meteoritic analogues of meteors

A Drouard,J Gattacceca,C Marmo,R Oefele,B Zanda,A Meindl,S Bouley,M Birlan,T Hermann,P Vernazza,J Vaubaillon,M Eberhart,F Zamkotsian,S Loehle,F Zander,F Colas,L Jorda

doi:10.1051/0004-6361/201732225

Abstract

Context. Determining the source regions of meteorites is one of the major goals of current research in planetary science. Whereas asteroid observations are currently unable to pinpoint the source regions of most meteorite classes, observations of meteors with camera networks and the subsequent recovery of the meteorite may help make progress on this question. The main caveat of such an approach, however, is that the recovery rate of meteorite falls is low (<20%), implying that the meteoritic analogues of at least 80% of the observed falls remain unknown. Aims. Spectroscopic observations of incoming bolides may have the potential to mitigate this problem by classifying the incoming meteoritic material. Methods. To probe the use of spectroscopy to determine the meteoritic analogues of incoming bolides, we collected emission spectra in the visible range (320–880 nm) of five meteorite types (H, L, LL, CM, and eucrite) acquired in atmospheric entry-like conditions in a plasma wind tunnel at the Institute of Space Systems (IRS) at the University of Stuttgart (Germany). A detailed spectral analysis including a systematic line identification and mass ratio determinations (Mg/Fe, Na/Fe) was subsequently performed on all spectra. Results. It appears that spectroscopy, via a simple line identification, allows us to distinguish the three main meteorite classes (chondrites, achondrites and irons) but it does not have the potential to distinguish for example an H chondrite from a CM chondrite. Conclusions. The source location within the main belt of the different meteorite classes (H, L, LL, CM, CI, etc.) should continue to be investigated via fireball observation networks. Spectroscopy of incoming bolides only marginally helps precisely classify the incoming material (iron meteorites only). To reach a statistically significant sample of recovered meteorites along with accurate orbits (>100) within a reasonable time frame (10–20 years), the optimal solution may be the spatial extension of existing fireball observation networks.

Highlights

Meteorites are a major source of material to contribute to the understanding of how the solar system formed and evolved (Hutchison et al 2001)
Spectroscopic observations of incoming bolides may have the potential to mitigate this problem by classifying the incoming meteoritic material
To probe the use of spectroscopy to determine the meteoritic analogues of incoming bolides, we collected emission spectra in the visible range (320–880 nm) of five meteorite types (H, L, LL, CM, and eucrite) acquired in atmospheric entry-like conditions in a plasma wind tunnel at the Institute of Space Systems (IRS) at the University of Stuttgart (Germany)

Summary

Introduction

Meteorites are a major source of material to contribute to the understanding of how the solar system formed and evolved (Hutchison et al 2001). They are rocks of extraterrestrial origin, mostly fragments of small planetary bodies such as asteroids or comets, some of which may have orbits that cross that of the Earth. It is very difficult to conclusively identify the parent bodies of most meteorite groups using ground-based observations and/or spacecraft data alone. This stems from the fact that most asteroids are not spectrally unique. There are plenty of plausible parent bodies for a given meteorite class (Vernazza et al 2014, 2016); the obvious

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Discussion

Conclusion