I.Hatsukade, H.Tsunemi, K.Yamashita, K.Koyama, Y.Asaoka and I.Asaoka

Abstract

Kepler's SNR was observed with the Large Area Counter on board the Ginga satellite in the energy range 1-12 keV. A strong iron K-alpha emission line has been found at 6.48 + or - 0.07 keV. This value is too low if the plasma has reached the collisinal ionization equilibrium condition and, therefore, indicates that the plasma is still in a nonequilibrium ionization (NEI) condition. Using a NEI model, the electron temperature, Te, is determined to be 4.5 + or - 0.3 keV, and the plasma parameter tau (the product of the electron number density and the elapsed time after the shock heating) to be 10 exp (10.24 + or - 0.03)/cu cm sec. The abundances of heavy elements were also determined; it was found that iron is overabundant by a factor of 15 + or - 2 compared to the cosmic value. The iron mass within the remnant was estimated to be about 0.01 solar mass, which is less than one tenth of that predicted by the theory for Type I SN.