Extraction of Solid State Features of Carbon Dust Grains in the ISM, from X-Ray Absorption Studies

Abstract

The subject of dust formation in space is important in diverse environments. The formation of dust proceeds towards the formation of stellar objects and planets. So, it becomes very important for us to know the composition and structure of the dust in order to understand the above mentioned complex systems. Carbon grains are considered for long to be very important candidates for the dust in the interstellar medium (ISM). Existence of carbon in graphite form in the ISM, is an unsolved problem. The present approach will provide a probe, complimentary to the existing ones. It involves extraction of solid state features of carbon dust grains in the ISM, from x-ray absorption studies. A general theory of X-Ray Absorption Fine Structure (XAFS) will be presented. An approximate evaluation of this theory is proposed which allows us to predict the structure of the constituents of the grain. Some case studies are presented for various configurations of graphite and diamond.