The plots here primarily come from the demo programs I created to give EZ a test drive.  The programs, which can be downloaded as part of the EZ software distribution (available at my home page), illustrate the use of EZ and can provide templates for your own experiments.   They use the standard interfaces and were not (too) difficult to write.   I hope they'll show that the system gives access to some interesting phenomena.

    The links below let you download pdf files, with each file containing several figures on separate pages.   Rather than have a lot of jpegs floating around, I decided just to show some example thumbnails here and provide the pdf files so you can view or print as you desire (the Acrobat pdf reader is available from Adobe at no charge).

    Demo 1 computes the zero age main sequences for Z=0.02, 0.001, 0.004, and 0.0001.   The variation with mass along the ZAMS is shown for luminosity, surface temperature, central temperature, central density, radius, P-P versus CNO nuclear reactions, opacity, nuclear burning time scale, and convection zones.

    Demo 2 begins with plots of the Hertzsprung-Russell diagram tracks and central temperature and density tracks for a sample of Z=0.02 stars over a wide range of initial mass.   The tracks are marked to show the location of break-even for the net power from nuclear reactions beyond hydrogen burning minus the total power lost to neutrino cooling (i.e., the onset of significant helium burning).   The temperature-density plots include lines showing the degeneracy contours for Psi equal 0, 5, and 100.   NOTE: For the massive stars, late stages of evolution depend critically on the details of wind-driven mass loss.   I've made no attempt to address this issue and simply use a Reimers' wind with eta=1 as a zeroth order approximation.

    Demo 2 also also looks in detail at a number of stars with masses from 0.3 Msun up to 100 Msun.   For each one, it traces the evolution of convection zones, burning zones, central abundances, power sources, neutrino cooling, and shows profiles taken at key moments along the way.   These are all simulated with convective overshooting and a Reimers' wind (eta=1).   The tests start at the Z=0.02 ZAMS and are terminated when either the core becomes highly degenerate or something such as a helium flash requires a timestep smaller than the dynamic timescale.

    In addition to the usual HR diagram and central temperature-density tracks, the figures include histories of the later values for radius, neutino losses, power from triple-alpha, power from alpha-capture, power from carbon burning, center degeneracy, and total metal fraction.   There are plots that trace the evolution of convection zones, burning zones, central abundances (of helium, carbon, oxygen, nitrogen, and neon), nuclear power sources, and neutrino cooling.   The burning zones are subdivided into regions producing at least 1 erg/g/sec.   The power is subdivided into sources: PP+CNO, triple-alpha, alpha-capture, other nuclear burning, and total neutrino cooling. The neutrino cooling is subdivided into its various sources: plasmon decay, bremsstrahlung, photoneutrinos, and pair production.   Finally, there are figures showing sets of profiles by mass coordinate taken at key moments along the entire evolution.   These have profiles for abundances, power sources, temperature, and density.

    Plots combining various Z's ­ It can also be instructive to look at a single plot combining the tracks for several metallicities at a given initial masss.   The following files show such combined H-R and T-Rho tracks for a selection of masses.

     The results are illustrated here by the H-R and T-Rho tracks for stars of 1 Msun and 6 Msun.

    Different Z's   ­   The initial ZAMS metallicity has a big effect on the evolution.   Here is a selection of several cases for comparison.

     For example, the following images show the H-R and T-Rho tracks for a 6 Msun star with Z's of 0.0001 and 0.03. The files have the complete sets of plots.

    Individual Stars ­  The wide range of initial masses provide illustrations of white dwarf formation (up to 0.7 Msun), helium core flash (up to 2 Msun), and helium core burning occurring under a hydrogen burning shell.   For the more massive stars (over 2 Msun), the period of helium burning in the core is followed by a stage of two burning shells, one consuming helium and the other hydrogen, over a growing carbon/oxygen core.   NOTE: As mentioned above, for the massive stars, late stages of evolution depend critically on the details of wind-driven mass loss.   I've made no attempt to address this issue and simply use a Reimers' wind with eta=1 as a zeroth order approximation.