22-EPN3-068: Vacuum Heating Effects on Spectroscopic Properties of Carbonaceous Chondrite Meteorites

Visit by Edward Cloutis and Cain Kiddell, University of Winnipeg (Canada), to TA2 Facility 5 – DLR Planetary Spectroscopy Laboratory (Germany).
Dates of visit: 10-17 December 2023

Report Summary: This project was designed to investigate how conditions that may have affected dark carbonaceous asteroids affect our ability to detect and characterise them. We specifically investigated how exposure of carbonaceous meteorites (which are presumed to derive from carbonaceous asteroids) to the vacuum of space, as well as to heating, affect their spectral reflectance properties. Heating of carbonaceous asteroids may occur during their accretion and decay of radioactive elements, or from close passes to the Sun. We studied a number of different classes of carbonaceous meteorites of low petrologic grade, and will compare them to similar meteorites that show evidence of heating.

We found that vacuum exposure has its greatest effect on the depth and shape of the 3 micron-region water absorption band, while the 2.7 micron region absorption feature, associated with hydroxyl (OH) was largely unaffected.Heating led to a number of spectral changes which we continue to investigate, however preliminary results indicate that heating can affect absorption bands associated with iron. We have also found that the changes in spectral reflectance properties are a function of heating temperature. This results should enable us to constrain the temperatures to which carbonaceous asteroids have been exposed, and provide insights into conditions that prevailed in the early Solar System.

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