# Research

### Mass-Radius relation of Neutron Star

• I put some labels and titles in my graphs that obtained from Python code yesterday. Python is very intuitive so it’s easy to use.

# Mass vs Central density
plt.title('Mass vs Central density for Polytrope n = 1')
plt.xlabel(r'Central density (\$g/cm^3\$)')
plt.ylabel(r'Mass (\$M_\bigodot\$)')
plt.plot(RHO_C,M_max, 'b.')
plt.show()

• I wrote a code which calculates the Lane-Emden equation of n =1 case. This result has very similar behavior with my previous TOV solver result. I can put legends in the graph thanks to this link.

plt.title('Mass vs Radius for Polytrope n = 1')
plt.ylabel(r'Mass (\$M_{\bigodot}\$)')
plt.plot(r/KM,mass_LE/MSOL, label='Lane-Emden')
plt.plot(soln.t/KM, soln.y[0]/MSOL, label='TOV')
plt.legend()
plt.show()

• I read the paper to understand the basics of the neutron star. I think I need to read Shapiro and Teukolsky’s book first.
• I have been reading the paper to learn about the equation of state (EOS) of neutron stars.
• For future research, I need to learn C and C++ in order to use LORENE and RNS code, either of which will be used for my project.

# Study

### Astronomy & Astrophysics

• I have read two Astrobites articles. I know one of the authors of the second paper. I met him in Taiwan about 4 years ago. He was very kind to students and told his story about his interests in Astrophysics and numerical simulations. During the week I had many opportunities to talk to him, and it was quite a good experience. I wish I would do good research like him in the future.

### English

• I have added 2 new words and studied 14 English words using Anki.
• I went to the ESL class in the evening.
• I listened to the radio for 30 minutes.

• None