[mesa-users] helium main sequence binary

[Ying Qin]

Hi Josiah,

Thank you so much for this reply!

I think I should clarify my aim clearly at first. I want to run mesa with a binary system, A Wolf-Rayet(WR) star and a compact star(NS).

1) WR model is set by using this model:  'zams_z2m2_y98.data’ in inlist1.
Also, I use the WR wind(Detmers et al.  A&A, 484,831-839,2008). I add WR wind by changing ‘run_star_extras.f’ from src folder, and put
use_other_wind = .true. and x_ctrl(1) = 1.0 in the inlist1. Sorry about the inlist1 I sent you in last email, I forgot to uncomment these two command lines before sending you(I also test Dutch wind)

2) About the two mass and separation of both stars, I put the following command lines in inlist_project(&binary_controls). The distance between the two stars is 48 hrs(0.2d0).
   m1 = 10.0d0  ! donor mass in Msun
   m2 = 1.40d0  ! companion mass in Msun
   initial_period_in_days = 0.2d0

After all setting above, I again run mesa, and now check the results from binary_history.data.
    model_number                 age                                                  binary_separation                              star_1_mass                                          lg_mstar_dot_1
          1                                 3.1622776601683819E+002           9.6975446700026726E+000             3.9637246692135668E+000                 -7.1000524704855197E+000
I know WR star lost mass very fast, these results are not what I expect now.
Why does WR star decrease mass from 3.9637246692135668E+000 ? I think the mass of WR should be decreasing from about 10.0.
Why does binary_separation change from 9.6975446700026726E+000 ? Because I initialize this it with 0.2d0.
For these results, I said there were random, Because they are not reasonable.

Also, I want star1 to evolve with zero age and zero model number, and I change these in inlist1:
      set_initial_age = .true.
      initial_age = 0 ! in years

      set_initial_model_number = .true.
      initial_model_number = 0

But from the results, we can clearly find it did not  work.

I use mea r7624, and copy binary/work directory.  I hope my questions are much clearer. The run_star_extra.f and inlist1 are as follows.
I think I missed something important. I am looking forward your reply to refresh my understanding. Thank you in advance!

With my best regards,
Ying



On 12 Sep 2015, at 06:43, Josiah Schwab <jwschwab at berkeley.edu<mailto:jwschwab at berkeley.edu>> wrote:

Hello Ying,

On 11 September 2015 at 13:50 PDT, Ying Qin wrote:

But from the binary_history.data, I find star 1 started to lose mass
from 2.2 at the beginning(about 300 yrs)

And binary_separation is approximately equal to 20 Rsun.

I ran the inlists you sent and didn't see either of these things.
(Though I didn't understand what "from 2.2" meant.)

The first line of binary_history.data had these entries:

                   age        binary_separation            lg_mstar_dot_1
3.1622776601683819E+002  3.2382327687009131E+000  -9.8999999999999986E+001

so the expected separation and no mass loss.

So what I had set in the list did not work.

What version of MESA are you using?  All I did was use the inlists you
sent with a fresh binary/work directory from r7624.

And mesa seems to create a random initial parameter.

I don't know what this means.

Josiah

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