On the problem of constraining the temperature of the circumsolar disc based on olivine components of carbonaceous chondrites
Meteorites of carbonaceous chondrites provide constrains on physical conditions of Solar system formation. Olivines and other minerals composed of Mg–Fe–Si-O are main components of carbonaceous chondrites. Experimental measurements of olivine formation temperature is necessary to constrain the temperature of the circumsolar disc as a source of olivines. We have conducted synthesis of forsterite under mild conditions of temperature and pressure. Calcination was carried out sequentially at 450, 550, 600, 650, 700, 750, 1000 and 1250 ° C for 6 hours. The samples were characterized by XRD and other techniques. Forsterite Mg2SiO4 forms at temperatures of 550 ° C and above. Note that under equilibrium conditions during the melting of a mixture of coarse crystalline oxides MgO and SiO2 we need 1890 ° C to form forsterite. Therefore, the area of the sircumsolar disc where meteorites were formed probably had mild temperature conditions, less than 550 ° C. The report discusses some dynamical processes in massive discs of young stellar objects which may provide the conditions of formation of carbonaceous chondrites.