Simulations of stellar winds from X-ray bursts. Characterization of solutions and observable variables

Abstract

Photospheric radius expansion during X-ray bursts can be used to measure neutron star radii and help constrain the equation of state of neutron star matter. Understanding the stellar wind dynamics is important for interpreting observations. Stellar wind models, though studied in past decades, have thus regained interest and need to be revisited with updated data and methods. In this work we study the radiative wind model in the context of XRBs, with modern techniques and physics input. We focus on characterization of the solutions and study of observable magnitudes as a function of free model parameters. We implement a spherically-symmetric non-relativistic wind model in a stationary regime, with updated opacity tables and modern numerical techniques. Total mass and energy outflows $(\dot{M},\dot{E})$ are treated as free parameters. A high resolution parameter space exploration was performed to allow better characterization of observable magnitudes. High correlation was found between different photospheric magnitudes and free parameters. For instance, the photospheric ratio of gravitational energy outflow to radiative luminosity is in direct proportion to the photospheric wind velocity. The correlations found could help determine the physical conditions of the inner layers, where nuclear reactions take place, by means of observable photospheric values. Further studies are needed to determine the range of physical conditions in which the correlations are valid.

arXiv commentAccepted in Astronomy and Astrophysics. New version with corrected typo in eq. (36) and some minor changes after language edition

References in corpus (12)

• Modules for Experiments in Stellar Astrophysics (MESA)
• The Equation of State from Observed Masses and Radii of Neutron Stars
• Thermonuclear (type-I) X-ray bursts observed by the Rossi X-ray Timing Explorer
• The endpoint of the rp process on accreting neutron stars
• Astrophysical Measurement of the Equation of State of Neutron Star Matter
• Models for Type I X-Ray Bursts with Improved Nuclear Physics
• Exposing the Nuclear Burning Ashes of Radius Expansion Type I X-ray Bursts
• Hydrodynamic Models of Type I X-Ray Bursts: Metallicity Effects
• Atomic Spectral Features During Thermonuclear Flashes on Neutron Stars
• Rotational Broadening of Atomic Spectral Features from Neutron Stars
• Formation of Resonant Atomic Lines during Thermonuclear Flashes on Neutron Stars
• Super-Eddington winds from Type I X-ray bursts

Cited by in corpus (4)

• Mass-loss and composition of wind ejecta in type I X-ray bursts
• Expanded atmospheres and winds in Type I X-ray bursts from accreting neutron stars
• Nucleosynthesis in Type Ia Supernovae, Classical Novae, and Type I X-Ray Bursts. A Primer on Stellar Explosions
• Neutron star atmospheres composed of fusion ashes