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Dust from collisions: A way to probe the composition of exo-planets?

Morlok, Andreas; Mason, Andrew B.; Anand, Mahesh; Lisse, Carey M.; Bullock, Emma S. and Grady, Monica M. (2014). Dust from collisions: A way to probe the composition of exo-planets? Icarus, 239 pp. 1–14.

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In order to link infrared observations of dust formed during planet formation in debris disks to mid-infrared spectroscopic data of planetary materials from differentiated terrestrial and asteroidal bodies, we obtained absorption spectra of a representative suite of terrestrial crustal and mantle materials, and of typical martian meteorites.

A series of debris disk spectra characterized by a strong feature in the 9.0–9.5 µm range (HD23514, HD15407a, HD172555 and HD165014), is comparable to materials that underwent shock, collision or high temperature events. These are amorphous materials such as tektites, SiO2-glass, obsidian, and highly shocked shergottites as well as inclusions from mesosiderites (group A).

A second group (BD+20307, Beta Pictoris, HD145263, ID8, HD113766, HD69830, P1121, and Eta Corvi) have strong pyroxene and olivine bands in the 9–12 µm range and is very similar to ultramafic rocks (e.g. harzburgite, dunite) (group B).

This could indicate the occurrence of differentiated materials similar to those in our Solar System in these other systems.

However, mixing of projectile and target material, as well as that of crustal and mantle material has to be taken into account in large scale events like hit-and-run and giant collisions or even large-scale planetary impacts. This could explain the olivine-dominated dust of group B.

The crustal-type material of group A would possibly require the stripping of upper layers by grazingstyle hit-and run encounters or high energy events like evaporation/condensation in giant collisions. In tidal disruptions or the involvement of predominantly icy/water bodies the resulting mineral dust would originate mainly in one of the involved planetesimals. This could allow attributing the observed composition to a specific body (such as e.g. Eta Corvi).

Item Type: Journal Item
Copyright Holders: 2014 Elsevier Inc.
ISSN: 0019-1035
Project Funding Details:
Funded Project NameProject IDFunding Body
Academic Fellowships: Open UniversityEP/E500226/1EPSRC (Engineering and Physical Sciences Research Council)
Astronomy Research at the Open University 2006 - 2011PP/D000963/1STFC (Science & Technology Facilities Council)
Keywords: debris disks; extra-solar planets; infrared observations; Earth; Mars; planetary formation
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Research Group: Space
Item ID: 45069
Depositing User: Mahesh Anand
Date Deposited: 07 Jan 2016 11:01
Last Modified: 31 May 2019 09:15
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