Nucleosynthesis in Baryon-Rich Outflows Associated With Gamma-Ray Bursts

Abstract

Robust generation of gamma-ray bursts (GRBs) implies the formation of outflows with very low baryon loads and highly relativistic velocities, but more baryon-rich, slower outflows are also likely to occur in most GRB central engine scenarios, either as ``circum-jet winds'' or ``failed GRBs''. Here we study the possibility of nucleosynthesis within such baryon-rich outflows by conducting detailed reaction network calculations in the framework of the basic fireball model. It is shown that high baryon load fireballs attaining mildly relativistic velocities can synthesize appreciable quantities of heavy neutron capture elements with masses up to the platinum peak and beyond. Small but interesting amounts of light elements such as deuterium and boron can also be produced. Depending on the neutron excess and baryon load, the combination of high entropy, rapid initial expansion and gradual expansion at later times can cause the reaction flow to reach the fission regime, and its path can be intermediate between those of the $r$- and $s$-processes (``$n$-process''). The nucleosynthetic signature of these outflows may be observable in the companion stars of black hole binary systems and in the most metal-poor stars, potentially offering an important probe of the inner conditions of the GRB source. Contribution to the solar abundances for some heavy elements may also be possible. The prospects for further developments in various directions are discussed.

ApJ, in press; 11 pages, 3 figures

References in corpus (8)

• A stellar relic from the early Milky Way
• Bipolar Supernova Explosions: Nucleosynthesis & Implication on Abundances in Extremely Metal-Poor Stars
• Nuclear Composition of Gamma-Ray Burst Fireballs
• Probing the Neutron-Capture Nucleosynthesis History of Galactic Matter
• The Origin of the Heavy Elements: Recent Progress in the Understanding of the r-Process
• Nucleosynthesis in Gamma Ray Burst Accretion Disks
• Stability analysis of relativistic jets from collapsars and its implications on the short-term variability of gamma-ray bursts
• Supernova Explosions from Accretion Disk Winds

Cited by in corpus (10)

• Sensitivity of r-Process Nucleosynthesis to Light-Element Nuclear Reactions
• Explosive Nucleosynthesis in GRB Jets Accompanied by Hypernovae
• Nucleosynthesis inside Gamma-Ray Burst Accretion Disks
• Electron Positron Capture Rates and the Steady State Equilibrium Condition for Electron-Positron Plasma with Nucleons
• X-ray clusters of galaxies in conformal gravity
• Light-Element Reaction Flow and the Conditions for r-Process Nucleosynthesis
• Neutron-rich gamma-ray burst flows: dynamics and particle creation in neutron - proton collisions
• Nucleosynthesis in the outflows associated with accretion disks of Type II collapsars
• Fireball anti-nucleosynthesis
• Alpha-constrained QSE Nucleosynthesis in High-entropy and Fast-expanding Material