amotornenko / tovsolver

Python package for solving TOV equation and calculating tidal properties

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Python for TOV solver

About

Python package to solve Tolman-Oppenheimer-Volkoff equation. Allows to study properties of static neutron stars with given equation of state. Additionally is able to calculate tidal properties of neutron stars. The package can become quite handy by using from jupyter noebook.

Documentation

To install use:

pip3 install .

Or if you do not have root access, then to install locally:

pip3 install . --user

See an example jupyter notebook in the example folder.

Functionality

Solves TOV equation, calculates mass and radius of static neutron star at given central density. Calculates tidal properties of neutron star.

Literature

• R. C. Tolman, Phys. Rev. 55, 364 (1939) Static Solutions of Einstein's Field Equations for Spheres of Fluid
• J. R. Oppenheimer and G. M. Volkoff, Phys. Rev. 55, 374 (1939) On Massive Neutron Cores
• G. Baym, C. Pethick, and P. Sutherland, Astrophys. J. 170, 299 (1971) The Ground State of Matter at High Densities: Equation of State and Stellar Models
• T. Hinderer, B. D. Lackey, R. N. Lang, and J. S. Read, Phys. Rev. D81, 123016 (2010) Tidal deformability of neutron stars with realistic equations of state and their gravitational wave signatures in binary inspiral

License

Copyright 2019-2022 Anton Motornenko (FIAS)

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

tovsolver's Issues

Run tov.py code

Hello,
I have installed the TOVsolver code as instructed.

Now I want to use my EoS to solve the TOV equation and calculate Mass, radius, etc.
Where do I need to save my EoS and how do I then run tov.py

Please respond back.
I will be waiting

Not a code problem, why are some images blank on the left side of the line.

For example, why can't the left side of the neutron star mass-radius relation curve continue to be drawn?

about the central density

Hello,
When I used my own EOS for calculation, I found that there was an exception in it, as shown in the figure, but I did not quite understand this exception and was not clear about its impact on the calculation results. I hope I can get your help.
Thank you.

Issue with the code

Hi ,
Can u tell me why this issue is coming

Gettting more mass if the central density is fixed either for maximum mass star or canonical star profiles

1. I have compiled your codes using these lines

m_arr = []
R_arr = []

for dens_c in np.logspace(-0,3.7,350):
R, M, prof = tov_s.solve(dens_c, rmax=50e5, dr=100)
m_arr.append(M)
R_arr.append(R)
print(R, M, dens_c) # extra I have written to check which central density gives the maximum mass of the neutron star.

I found that the radius and central density corresponded to the maximum mass 2.1498973233892715 M_sun are

12.004 km 1076.692506643068 MeV/fm^3

2. Now, I have fixed only this central density to check whether i am getting the same or not. But it gives me wrong values.

R, M, prof = tov_s.solve(1076.692506643068, rmax=50e5, dr=100) # 2.1498973233892715 M_sun, 12.004 km

12.004 km 4.274931084233547 M_sun

If you compare the masses there is huge differences 4.274931084233547-2.1498973233892715 = 2.125033761 M_sun. But the radius is same.

3. For arbitrary star say mass 1.3820322317287081 M_sun, the radius and central density are 13.144 km and 386.20641587213856 Mev/fm^3

R, M, prof = tov_s.solve(386.20641587213856, rmax=50e5, dr=100) # 1.3820322317287081, 13.144

print(max(prof[0]/1e5), max(prof[3]/1e33)) gives

13.144 km 2.748081260697474 M_sun

Please help me in this regard.