Reaction Rate and Composition Dependence of the Stability of Thermonuclear Burning on Accreting Neutron Stars

Abstract

The stability of thermonuclear burning of hydrogen and helium accreted onto neutron stars is strongly dependent on the mass accretion rate. The burning behavior is observed to change from Type I X-ray bursts to stable burning, with oscillatory burning occurring at the transition. Simulations predict the transition at a ten times higher mass accretion rate than observed. Using numerical models we investigate how the transition depends on the hydrogen, helium, and CNO mass fractions of the accreted material, as well as on the nuclear reaction rates of triple alpha and the hot-CNO breakout reactions 15O(a,g)19Ne and 18Ne(a,p)21Na. For a lower hydrogen content the transition is at higher accretion rates. Furthermore, most experimentally allowed reaction rate variations change the transition accretion rate by at most 10%. A factor ten decrease of the 15O(a,g)19Ne rate, however, produces an increase of the transition accretion rate of 35%. None of our models reproduce the transition at the observed rate, and depending on the true 15O(a,g)19Ne reaction rate, the actual discrepancy may be substantially larger. We find that the width of the interval of accretion rates with marginally stable burning depends strongly on both composition and reaction rates. Furthermore, close to the stability transition, our models predict that X-ray bursts have extended tails where freshly accreted fuel prolongs nuclear burning.

arXiv comment12 pages, 14 figures. Submitted for publication in ApJ

References in corpus (32)

• Modelling the behaviour of accretion flows in X-ray binaries
• Astrophysical Reaction Rates From Statistical Model Calculations
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• Models for Type I X-Ray Bursts with Improved Nuclear Physics
• Heating in the Accreted Neutron Star Ocean: Implications for Superburst Ignition
• Nuclear composition and heating in accreting neutron-star crusts
• The Effects of Variations in Nuclear Processes on Type I X-Ray Burst Nucleosynthesis
• Six years of BeppoSAX Wide Field Cameras observations of nine galactic type-I X-ray bursters
• Strong neutrino cooling by cycles of electron capture and ${\beta }^{-}$ decay in neutron star crusts
• Models of Type I X-ray Bursts from GS 1826-24: A Probe of rp-Process Hydrogen Burning
• Hydrodynamic Models of Type I X-Ray Bursts: Metallicity Effects
• New class of low frequency QPOs: signature of nuclear burning or accretion disk instabilities?
• Millihertz Quasi-Periodic Oscillations from Marginally Stable Nuclear Burning on an Accreting Neutron Star
• Thermonuclear Stability of Material Accreting onto a Neutron Star
• Millihertz quasi-periodic oscillations and thermonuclear bursts from Terzan 5: A showcase of burning regimes
• Thermonuclear Burning on the Accreting X-Ray Pulsar GRO J1744-28
• First superburst from a classical low-mass X-ray binary transient
• Superburst Models for Neutron Stars with Hydrogen and Helium-Rich Atmospheres
• The importance of 15O(a,g)19Ne to X-ray bursts and superbursts
• Millihertz Oscillation Frequency Drift Predicts the Occurrence of Type I X-ray Bursts
• The ${}^{15}$O($\alpha$,$\gamma$)${}^{19}$Ne Breakout Reaction and Impact on X-Ray Bursts
• The effect of rotation on the stability of nuclear burning in accreting neutron stars
• Turbulent Mixing in the Surface Layers of Accreting Neutron Stars
• Multi-Zone Models of Superbursts from Accreting Neutron Stars
• The Influence of Uncertainties in the 15O(alpha,gamma)19Ne Reaction Rate on Models of Type I X-Ray Bursts
• The 18Ne(a,p)21Na breakout reaction in x-ray bursts: experimental determination of spin-parities for alpha resonances in 22Mg via resonant elastic scattering of 21Na+p
• Two-phase X-ray burst from GX 3+1 observed by INTEGRAL
• A Two-Zone Model for Type I X-ray Bursts on Accreting Neutron Stars
• Metallicity-Dependent Galactic Isotopic Decomposition for Nucleosynthesis
• On the Physics of Type I X-ray Bursts on Accreting Neutron Stars at High Accretion Rates
• Making Carbon in Stars
• The superburst recurrence time in luminous persistent LMXBs

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