Sensitivity Study of Type-I X-ray Bursts to Nuclear Reaction Rates

Type I X-ray Bursts at Low Accretion Rates

Neutron stars, with their strong surface gravity, have interestingly short timescales for the sedimentation of heavy elements. Recent observations of unstable thermonuclear burning (observed as X-ray bursts) on the surfaces of slowly accreting neutron stars (< 0.01 of the Eddington rate) motivate us to examine how sedimentation of CNO isotopes affects the ignition of these bursts. We further es...

The Affect of Nuclear Reaction Rates in Type-I X-Ray Bursts on the Ignition of Superbursts

Exposing the Nuclear Burning Ashes of Radius Expansion Type I X-ray Bursts

We solve for the evolution of the vertical extent of the convective region of a neutron star atmosphere during a Type I X-ray burst. The convective region is well-mixed with ashes of nuclear burning due to the short turbulent mixing time scale and its extent determines the rise time of the burst light curve. Using a full nuclear reaction network, we show that the maximum vertical extent of the ...

Sedimentation and Type I X-ray Bursts at Low Accretion Rates

Neutron stars, with their strong surface gravity, have interestingly short timescales for the sedimentation of heavy elements. Motivated by observations of Type I X-ray bursts from sources with extremely low persistent accretion luminosities, LX < 10 36 ergs s(≃ 0.01LEdd), we study how sedimentation affects the distribution of isotopes and the ignition of H and He in the envelope of an accretin...

Torsional Magnetic Oscillations in Type I X-ray Bursts

Thermonuclear burning on the surface of a neutron star causes the expansion of a thin outer layer of the star, ∆R(t). The layer rotates slower than the star due to angular momentum conservation. The shear between the star and the layer acts to twist the star’s dipole magnetic field giving at first a trailing spiral field. The twist of the field acts in turn to ‘torque up’ the layer increasing i...