moon_sleep150.gif
Cococubed.com


Proton-rich NSE

Home

Astronomy research
  Software Infrastructure:
     MESA
     FLASH-X
     STARLIB
     MESA-Web
     starkiller-astro
     My instruments
  White dwarf pulsations:
     12C(α,γ) & overshooting
     Probe of 12C(α,γ)16O
     Impact of 22Ne
     Impact of ν cooling
     Variable white dwarfs
     MC reaction rates
     Micronovae
     Novae
  White dwarf supernova:
     Stable nickel production
     Remnant metallicities
     Colliding white dwarfs
     Merging white dwarfs
     Ignition conditions
     Metallicity effects
     Central density effects
     Detonation density
     Tracer particle burning
     Subsonic burning fronts
     Supersonic fronts
     W7 profiles
  Massive stars:
     Pop III with HST/JWST
     Rotating progenitors
     3D evolution to collapse
     MC reaction rates
     Pre-SN variations
  Massive star supernova:
     Yields of radionuclides
     26Al & 60Fe
     44Ti, 60Co & 56Ni
     SN 1987A light curve
     Constraints on Ni/Fe
     An r-process
     Effects of 12C +12C
  Neutron Stars and Black Holes:
     Black Hole spectrum
     Mass Gap with LVK
     Compact object IMF
     He burn neutron stars
  Neutrino Emission:
     Neutrino emission from stars
     Identifying the Pre-SN
     Neutrino HR diagram
     Pre-SN Beta Processes
     Pre-SN neutrinos
  Stars:
     Hypatia catalog
     SAGB stars
     Nugrid Yields I
     He shell convection
     BBFH at 40 years
     γ-rays within 100 Mpc
     Iron Pseudocarbynes
  Pre-Solar Grains:
     C-rich presolar grains
     SiC Type U/C grains
     Grains from massive stars
     Placing the Sun
     SiC Presolar grains
  Chemical Evolution:
     Radionuclides in 2020s
     Zone models H to Zn
     Mixing ejecta
  Thermodynamics, Opacities & Networks
     Radiative Opacity
     Skye EOS
     Helm EOS
     Five EOSs
     Equations of State
     12C(α,γ)16O Rate
     Proton-rich NSE
     Reaction networks
     Bayesian reaction rates
  Verification Problems:
     Validating an astro code
     Su-Olson
     Cog8
     Mader
     RMTV
     Sedov
     Noh
Software Instruments
AAS Journals
   2024 AAS YouTube
   2024 AAS Peer Review Workshops

2024 ASU Energy in Everyday Life
2024 MESA Classroom
Outreach and Education Materials

Other Stuff:
   Bicycle Adventures
   Illustrations
   Presentations



Contact: F.X.Timmes
my one page vitae,
full vitae,
research statement, and
teaching statement.
Proton-rich Nuclear Statistical Equilibrium (2008)

Proton-rich material in a state of nuclear statistical equilibrium (NSE) is one of the least studied regimes of nucleosynthesis. One reason for this is that after hydrogen burning, stellar evolution proceeds at conditions of an equal number of neutrons and protons or at a slight degree of neutron-richness. Proton-rich nucleosynthesis in stars tends to occur only when hydrogen-rich material that accretes onto a white dwarf or a neutron star explodes, or when neutrino interactions in the winds from a nascent proto-neutron star or collapsar disk drive the matter proton-rich prior to or during the nucleosynthesis.

In this letter we solve the NSE equations for a range of proton-rich thermodynamic conditions. We show that cold proton-rich NSE is qualitatively different from neutron-rich NSE. Instead of being dominated by the Fe-peak nuclei with the largest binding energy per nucleon that have a proton-to-nucleon ratio close to the prescribed electron fraction, NSE for proton-rich material near freezeout temperature is mainly composed of 56Ni and free protons. We show how the differences and especially the large fraction of free protons arises from the minimization of the free energy as a result of a competition between the entropy and nuclear binding energy.

image
ρ=107 g/cc, T=9×109 K
image
ρ=107 g/cc, T=3.5×109 K.
image
Helmholtz free energy



NSE Software Instrument

Open source software for NSE are avaliable here.