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V. A. Simonenko D. A. Gryaznykh I. A. Litvinenko V. A. Lykov A. N. Shushlebin 《Astronomy Letters》2012,38(4):231-237
Some thermonuclear X-ray bursters exhibit a high-frequency (about 300 Hz or more) brightness modulation at the rising phase
of some bursts. These oscillations are explained by inhomogeneous heating of the surface layer on a rapidly rotating neutron
star due to the finite propagation speed of thermonuclear burning. We suggest and substantiate a mechanism of this propagation
that is consistent with experimental data. Initially, thermonuclear ignition occurs in a small region of the neutron star
surface layer. The burning products rapidly rise and spread in the upper atmospheric layers due to turbulent convection. The
accumulation of additional matter leads to matter compression and ignition at the bottom of the layer. This determines the
propagation of the burning front. To substantiate this mechanism, we use the simplifying assumptions about a helium composition
of the neutron star atmosphere and its initial adiabatic structure with a density of 1.75 × 108 g cm−3 at the bottom. 2D numerical simulations have been performed using a modified particle method in the adiabatic approximation. 相似文献