Initial periods and mass transfer

Show how initial periods are different for mass transferring binaries.

Mass transferring binaries generally started with shorter periods.

import cogsworth
import matplotlib.pyplot as plt
import numpy as np



p = cogsworth.pop.Population(5000, processes=1, BSE_settings={"binfrac": 1.0})
p.sample_initial_binaries()
p.perform_stellar_evolution()

fig, ax = plt.subplots()

mt_bin_nums = p.bpp[p.bpp["evol_type"] == 3]["bin_num"].unique()
no_mt_bin_nums = p.bin_nums[~np.isin(p.bin_nums, mt_bin_nums)]
porb_init = np.log10(p.initC["porb"])

bins = np.linspace(0, 5, 20)

ax.hist(porb_init, bins=bins, density=True, label="All binaries")
ax.hist(porb_init.loc[mt_bin_nums], bins=bins, alpha=0.5, density=True, label="Mass transfer binaries")

ax.legend()

ax.set_xlabel("Initial period [log days]")
ax.set_ylabel(r"${\rm d}N/{\rm d}({\rm log} P)$")

plt.show()