We calculate the thermal and dynamical evolution of the surface layers of an accreting neutron star during the rise of a superburst. For the first few hours following unstable C ignition, the nuclear energy release is transported by convection. However, as the base temperature rises, the heating time becomes shorter than the eddy turnover time and convection becomes inefficient. This results in...

We present a comprehensive study of the thermonuclear bursts and millihertz quasi-periodic oscillations (mHz QPOs) from the neutron star (NS) transient and 11 Hz X-ray pulsar IGR J17480–2446, located in the globular cluster Terzan 5. The increase in burst rate that we find during its 2010 outburst, when persistent luminosity rises from 0.1 to 0.5 times the Eddington limit, is in qualitative agr...

Type Ia Supernovae (SNe Ia) may originate from a wide variety of explosion scenarios and progenitor channels. They exhibit factor about 10 difference in brightness and, thus, differentiation the mass 56Ni->56Co->56 Fe. We present study on fate positrons within SNe order to evaluate their escape fractions energy spectra. Our detailed Monte Carlo transport simulations for gamma-rays include both ...