Presolar Grains - Types of Presolar Material

Types of Presolar Material

Presolar grains consisting of the following minerals have so far been identified:

  • diamond (C) nanometer-sized grains (~ 2.6 nm diameter) possibly formed by vapor deposition
  • graphite (C) particles and onions, some with unlayered graphene cores
  • silicon carbide (SiC) submicrometer to micrometer sized grains. Presolar SiC occurs as single-polytype grains or polytype intergrowths. The atomic structures observed contain the two lowest order polytypes: hexagonal 2H and cubic 3C (with varying degrees of stacking fault disorder) as well as 1-dimensionally disordered SiC grains. In comparison, terrestrial laboratory synthesized SiC is known to form over a hundred different polytypes.
  • titanium carbide (TiC) and other carbides within C and SiC grains
  • silicon nitride (Si3N4)
  • corundum (Al2O3)
  • spinel (MgAl2O4)
  • hibonite ((Ca,Ce)(Al,Ti,Mg)12O19)
  • titanium oxide (TiO2)
  • silicate minerals (olivine and pyroxene)

Read more about this topic:  Presolar Grains

Famous quotes containing the words types of, types and/or material:

    “... there are two types of happiness and I have chosen that of the murderers. For I am happy. There was a time when I thought I had reached the limit of distress. Beyond that limit, there is a sterile and magnificent happiness.”
    —Albert Camus (1913–1960)

    “Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
    —Talcott Parsons (1902–1979)

    “It may be possible to do without dancing entirely. Instances have been known of young people passing many, many months successively, without being at any ball of any description, and no material injury accrue either to body or mind; Mbut when a beginning is made—when felicities of rapid motion have once been, though slightly, felt—it must be a very heavy set that does not ask for more.”
    —Jane Austen (1775–1817)