Interplanetary material as a guide to the composition of interstellar grains

Open Access
Publisher Website
Google Scholar
Abstract
A compositional model for interstellar magnesium-iron silicate and iron-containing grains is derived under the constraint of elemental depletions, and using the composition of primitive Solar System material as a paradigm of the interstellar particles. The Solar System material invoked includes both chondritic porous aggregate interplanetary dust particles and unequilibriated ordinary chondritic meteorites. It is shown that the interstellar silicate grains are olivine rich (olivine-to-pyroxene grain mass ratio >0.8) and are iron rich (magnesium-to-iron atomic ratio > 0.65). Iron not incorporated into silicates is assumed to be depleted into the iron sulphide pyrrhotite which makes up <6 per cent of the refractory grain mass. The inclusion of grains of this magnetic sulphide into aggregate interstellar grains can explain the alignment of the grains responsible for the polarization in the visual.

This publication has 0 references indexed in Scilit: