Experimental constraints on the ordinary chondrite shock darkening caused by asteroid collisions

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F67985831%3A_____%2F20%3A00541398" target="_blank" >RIV/67985831:_____/20:00541398 - isvavai.cz</a>

Result on the web

<a href="https://www.aanda.org/articles/aa/pdf/2020/07/aa37593-20.pdf" target="_blank" >https://www.aanda.org/articles/aa/pdf/2020/07/aa37593-20.pdf</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1051/0004-6361/202037593" target="_blank" >10.1051/0004-6361/202037593</a>

Result language

angličtina

Original language name

Experimental constraints on the ordinary chondrite shock darkening caused by asteroid collisions

Original language description

Context. Shock-induced changes in ordinary chondrite meteorites related to impacts or planetary collisions are known to be capable of altering their optical properties. Thus, one can hypothesize that a significant portion of the ordinary chondrite material may be hidden within the observed dark C/X asteroid population.nAims. The exact pressure-temperature conditions of the shock-induced darkening are not well constrained. Thus, we experimentally investigate the gradual changes in the chondrite material optical properties as a function of the shock pressure.nMethods. A spherical shock experiment with Chelyabinsk LL5 was performed in order to study the changes in its optical properties.The spherical shock experiment geometry allows for a gradual increase of shock pressure from∼15 GPa at a rim toward hundreds of gigapascals in the center.nResults. Four distinct zones were observed with an increasing shock load. The optical changes are minimal up to ∼50 GPa. In the region of ∼50–60 GPa, shock darkening occurs due to the troilite melt infusion into silicates. This process abruptly ceases at pressures of ∼60 GPa due to an onset of silicate melting. At pressures higher than ∼150 GPa, recrystallization occurs and is associated with a second-stage shock darkening due to fine troilite-metal eutectic grains. The shock darkening affects the ultraviolet, visible, and near-infrared region while changes to the MIR spectrum are minimal.nConclusions. Shock darkening is caused by two distinct mechanisms with characteristic pressure regions, which are separated by an interval where the darkening ceases. This implies a reduced amount of shock-darkened material produced during the asteroid collisions.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

—

Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Astronomy & Astrophysics

ISSN

0004-6361

e-ISSN

1432-0746

Volume of the periodical

639

Issue of the periodical within the volume

July 2020

Country of publishing house

FR - FRANCE

Number of pages

13

Pages from-to

A146

UT code for WoS article

000556673800002

EID of the result in the Scopus database

2-s2.0-85089354108