Template:ASTR508/Assignment2

Using sample_zams as a starting point, generate a CMD in MV vs B-V for a solar metallicity ZAMS and for the metallicity of 47 Tuc (create_zams). If you assume that stars stay the same colour and luminosity on the MS (not strictly true), what does the CMD look like at an age of 10 Myr, 100 Myr, 1 Gyr and 10 Gyr? Using your solar metallcity ZAMS at 100 Myr figure out the distance to the Pleiades and at 10 Gyr for 47 Tuc. You will have to edit the specification file. Use the value of log(tnuc) to estimate which stars are alive after a given time. That is, for 1 Gyr only plot stars with log(tnuc)>9.

For the 47 Tuc model with (create_zams) you will have to remove the line from run_star_extras.f that gets it to stop (look in the docs directory for a hint) and put a control in run_star.extras.f to get it to stop at the end of H-burning, say when the central hydrogen fraction is less than one percent. You can use the star pointer variable: s % center_h1. Make it like the code that you just deleted. The routines create_zams and sample_zams do not make files in the LOG directory, so you will use the final console output to get the data that you need.

Generate a CMD for a solar mass star through its entire lifetime (here both L vs Teff and MV vs B-V). Divide the star's history into various stages by looking at the external observables as a function of time. What is going on inside the star during each of these stages? Start with the 1M_pre_ms_to_wd inlist.

You will find the table below useful to convert luminosity and effective temperature to colour.

# SpTyp  MV   BC   MBol   B-V   L/Lsun    Teff  Mass
#  1     2    3     4      5      6        7      8 
  M6  16.5   4.3 12.20  1.7  1.0568e-03   2600  0.17
  M4  12.7   2.7 10.00  1.6  8.0168e-03   3200  0.25
  M2  11.2   1.7  9.50  1.5  1.2706e-02   3400  0.3
  M0   8.9   1.2  7.70  1.41 6.6681e-02   3800  0.35
  K7   8.3   1.0  7.30  1.32 9.6383e-02   4000  0.47
  K5   7.5   0.6  6.90  1.08 1.3932e-01   4350  0.69
  K0   5.9   0.4  5.50  0.84 5.0582e-01   5250  0.78
  G5  4.93   0.2  4.73  0.69 1.0280e+00   5700  0.93
 Sun  4.83  0.07  4.76  0.65 1.0000e+00   5780  1
  G0   4.2   0.2  4.00  0.59 2.0137e+00   6000  1.10
  F5   3.3   0.1  3.20  0.41 4.2073e+00   6500  1.3
  F0   2.4   0.1  2.30  0.32 9.6383e+00   7300  1.7
  A5   1.8   0.1  1.70  0.19 1.6749e+01   7800  2.1
  A0   0.8   0.3  0.50  0.0  5.0582e+01   9400  3.2
  B8 -0.25   0.8 -1.05 -0.11 2.1086e+02  11600  4
  B6  -1.0   1.2 -2.20 -0.14 6.0814e+02  14000  5
  B3  -1.4   1.6 -3.00 -0.18 1.2706e+03  18750  11
  B0  -3.7   3.0 -6.70 -0.30 3.8371e+04  30500  18
  O8  -4.3   3.3 -7.60 -0.321 8.7902e+04  35000  20
  O5  -5.2   3.8 -9.00 -0.322 3.1915e+05  41000  35
  O3  -5.8   4.0 -9.80 -0.323 6.6681e+05  44500  40

To log out from your computer but still have your job run, you will need to disown the job. Here is how. Type "jobs" at the prompt. Find the job in question, and type "disown %1" if it is job number 1. If you type "jobs" again you should find that the job is no longer on the list. If you run "top", you will see the job on the top of the list and you can kill it if you want by typing in the job number.

We have developed a more sophisticated tool to convert the MESA output files to the observable fluxes. It is called paintisochrone.py You can download it at

gcwd.tar.gz

with instructions and lots of ancillary files so that you can try it out.