Follows the thermal evolution of the outer layers of a neutron star after a thermonuclear flash. Based on the code used in Cumming & Macbeth (2004) and Cumming et al. (2006) ApJ papers.

To compile, first install

• GNU Scientific Library GSL
• condegin13.f fortran routine by A. Potekhin to calculate thermal conductivity (put in directory c, you may need to remove deprecated 'pause' and 'stop' statements)

then

mkdir o
mkdir out
make burstcool

should compile the code burstcool (you may need to change the compiler specified in the makefile to whatever compiler you are using).

Parameters are given in the file init.dat:

• E18: energy per gram in 10^18 erg/g (roughly 1 MeV/nuc = 10^18 erg/g)
• yb: base column depth (can be the actual number, or base 10 log, e.g. 1e12 or 12.0 will work)
• yt: column depth at the top of the grid
• burn: a flag to indicate the initial temperature profile - 0=instantaneous burn (local deposition of energy), 1=adiabatic slope if the parameter is <0, or sets del= if is >0
• time_to_run: seconds to run for (neutron star surface time)
• mass and radius: optional parameters to specify the mass and radius (you should give either both or none, default is 1.4 solar masses, 12 km)
• distance:
• output: Boolean for output to files (default 1)
• icool: Index of the grid cell for the cooling source (default 32)
• L34: Luminosity of the cooling source (default 0)
• ydeep_factor: default 100, y heating/base (heating at 1e12,base at 1e14 if ydeepfactor=100) (target column depth, but based on grid construction its not exactly right)
• deep_composition :
• shallow_composition :
• envelope_file : If a specific envelope file (envelope_models/file) should be read to obtain the base F-T relation. Default is to decide based on composition ("none")
• env_g : Value of g used in envelope calculations. burstcool will scale the F-T relation to match gravity. Default is 2.45e14

The code produces three output files in the directory out:

• out/prof - one line per timestep giving luminosity etc., e.g. use this to plot the lightcurve
• out/out - full details of the layer structure as a function of time
• a line is added to out/summary with information such as the total energy radiated from the surface or in neutrinos etc.
• info.txt - full description of output files, variables and units
• More detailed information on all outputs is given in the info.txt file

plot.pro has IDL routines to make plots. To make a movie (uses ffmpeg):

make cleanpng

idl
.com plot
prof2, /png

make movie      # not functionnal on current ffmpeg (?)

plot.py has python3 functions to make plots. To make a movie:

  make cleanpng
  python plot.py prof2
  make movie2

Published lightcurves from this code

• Cumming & Macbeth (2004) The Thermal Evolution following a Superburst on an Accreting Neutron Star
• Cumming et al. (2006) Long Type I X-ray Bursts and Neutron Star Interior Physics
• in 't Zand et al. (2014) The Cooling Rate of Neutron Stars after Thermonuclear Shell Flashes