Received ; accepted – 2 – ABSTRACT Since the classical work by Purcell (1979) it has been generally accepted that most interstellar grains rotate suprathermally. Suprathermally rotating grains would be nearly perfectly aligned with the magnetic field by paramagnetic dissipation if not for " crossovers " , intervals of low angular velocity resulting from reversals of the torques responsible for ...

Introduction: Most presolar SiC grains (~93%) have Si isotopic ratios that fall along the so-called mainstream correlation line of 1.37 on a Si three isotope plot [1]. Z grains, which constitute only ~1% of the total presolar SiC population, plot on the 30 Si-rich side of this line and typically have negative δ 29 Si/ 28 Si values, suggesting that they originated in asymptotic giant branch star...

Presolar grains are considered to have traces in their birth before the solar system formation in their isotopic and elemental features. Most of silicon carbide type X (SiC X) and low density graphite grains show the excesses of 12C and 28Si. These isotopic features suggest that SiC X and low density graphite are originating from supernovae. On the other hand, elemental signatures of the grains...

A search was conducted for grains of the potential core-collapse supernova (SN) condensate minerals corundum (Al2O3), hibonite (CaAl12O19), and spinel (MgAl2O4) among grains filtered from the 308.6 m Guliya ice core recovered from the Qinghai-Tibetan plateau in China. Simple models are developed and calculations are presented to estimate the number of Al2O3 grains that would be deposited per cm...

Investigations have been carried out on the distribution of AgBr-grains in unexposed photographic plates (type Q2, 11 f o r d Ltd.) used for ion detection in mass-spectrometers. Electron micrographs show that a large fraction of the grains protrude about halfway out of the gelatine matrix and that these grains are covered by a very thin gelatine layer on the side facing the ions. The mean proje...

The interaction of dust grains originating from the local interstellar cloud with the environment inside the heliosphere is investigated. As a consequence of this interaction the spatial distribution of interstellar dust grains changes with time. Since dust grains are charged in the interplanetary plasma and radiation environment, the interaction of small grains with the heliosphere is dominate...

Motivated by a recent study by Lazarian and Draine, which showed that a high degree of grain alignment of the paramagnetic dust is achievable if the rates of internal relaxation are controlled by the Barnett relaxation process, we undertake a study of an alternative mechanism of internal dissipation, namely, the inelastic dissipation of energy in oblate dust grains. We find that deformations at...

Motivated by a recent study by Lazarian and Draine, which showed that a high degree of grain alignment of the paramagnetic dust is achievable if the rates of internal relaxation are controlled by the Barnett relaxation process, we undertake a study of an alternative mechanism of internal dissipation, namely, the inelastic dissipation of energy in oblate dust grains. We find that deformations at...

Spontaneous stratification in granular mixtures—i.e., the formation of alternating layers of small-rounded and large-faceted grains when one pours a random mixture of the two types of grains into a quasi-twodimensional vertical Hele-Shaw cell—has been recently reported by H. A. Makse et al. @Nature 386, 379 ~1997!#. Here we study experimentally the dynamical processes leading to spontaneous str...

Introduction: Isheyevo is a metal-rich carbonaceous chon-drite with metal-rich and metal-poor lithologies that are most similar to the CBb and CH chondrites, respectively [1]. All consist of similar components – Fe,Ni metal, chondrules, refractory inclusions, amoeboid olivine aggregates and heavily hydrated lithic clasts. We continued our investigation of these components of Isheyevo and found ...