Meteorites & Asteroids

Mid-infrared Spectra Of The Shocked Murchison CM Chondrite: Comparison With Astronomical Observations Of Dust In Debris Disks

By Keith Cowing
Press Release
astro-ph.EP
January 2, 2023
Filed under , , , ,
Mid-infrared Spectra Of The Shocked Murchison CM Chondrite: Comparison With Astronomical Observations Of Dust In Debris Disks
[LEFT] Fig. 3: Comparison of astronomical infrared spectra of dust in selected debris disks to laboratory infrared spectra of shocked Murchison matrix samples. Top: Beta Pictoris and BD+20307 vs. Murchison shocked at 34 GPa. The spectrum from Okamoto et al. (2004) was taken from the central part of Beta Pictoris (<3.2 AU). Middle: HD113766 vs. Murchison shocked at 49 GPa. Bottom: HD69830 vs. Murchison shocked at 36 and 49 GPa (a mixture of 2/3 of the 36 GPa spectrum and 1/3 of the 49 GPa spectrum). Vertical broken lines indicate olivine features. The intensities of spectra are presented in linear arbitrary units. [RIGHT] Fig. 4: Comparison of spectra of dust in selected transitional disks to spectra of shocked Murchison matrix samples. Top: GM Aur vs. Murchison shocked at 21−34 GPa (an average of the 21−34 GPa spectra). Bottom: HD100546 vs. Murchison shocked at 36 and 49 GPa (a mixture of 2/3 of the 36 GPa spectrum and 1/3 of the 49 GPa spectrum). Vertical broken lines indicate olivine features. -- astro-ph.EP

We present laboratory mid-infrared transmission/absorption spectra obtained from matrix of the hydrated Murchison CM meteorite experimentally shocked at peak pressures of 10 to 49 GPa, and compare them to astronomical observations of circumstellar dust in different stages of the formation of planetary systems.

The laboratory spectra of the Murchison samples exhibit characteristic changes in the infrared features. A weakly shocked sample (shocked at 10 GPa) shows almost no changes from the unshocked sample dominated by hydrous silicate (serpentine). Moderately shocked samples (21 to 34 GPa) have typical serpentine features gradually replaced by bands of amorphous material and olivine with increasing shock pressure.

A strongly shocked sample (36 GPa) shows major changes due to decomposition of the serpentine and due to devolatilization. A shock melted sample (49 GPa) shows features of olivine recrystallized from melted material. The spectra of highly shocked Murchison samples (36 and 49 GPa) are similar to those of dust in the debris disks of HD113766 and HD69830, and the transitional disk of HD100546. The moderately shocked samples (21 to 34 GPa) exhibit spectra similar to those of dust in the debris disks of Beta Pictoris and BD+20307, and the transitional disk of GM Aur.

An average of the spectra of all Murchison samples (0 to 49 GPa) has a similarity to the spectrum of the older protoplanetary disk of SU Auriga. In the gas-rich transitional and protoplanetary disks, the abundances of amorphous silicates and gases have widely been considered to be a primary property.

However, our study suggests that impact processing may play a significant role in generating secondary amorphous silicates and gases in those disks. Infrared spectra of the shocked Murchison samples are also suggesting that the comets also contain shocked Murchison-like material.

A. Morlok, C. Koike, N. Tomioka, I. Mann, K. Tomoeka

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2212.14248 [astro-ph.EP] (or arXiv:2212.14248v1 [astro-ph.EP] for this version)
Journal reference: Icarus (2010), Volume 207, Issue 1, p. 45-53
Related DOI:
https://doi.org/10.1016/j.icarus.2009.11.018
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Submission history
From: Andreas Morlok
[v1] Thu, 29 Dec 2022 10:07:56 UTC (969 KB)
https://arxiv.org/abs/2212.14248
Astrobiology, Astrochemistry,

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