The Density Profile of a Neutron Star

Area of Science:

• Astrophysics and Nuclear Physics
• Relativistic Astrophysics
• Computational Physics

Background:

• Neutron stars possess extreme densities and strong gravitational fields, necessitating relativistic corrections for accurate modeling.
• Understanding internal density distribution is crucial for constraining neutron star properties and testing fundamental physics.

Purpose of the Study:

• To determine neutron star density distribution using volumetrically averaged density and moment of inertia factor (f).
• To apply the minimum relative entropy (MRE) methodology for calculating effective densities within neutron stars.
• To analyze relativistic effects on density, length, and moment of inertia calculations.

Main Methods:

• Utilized the minimum relative entropy (MRE) methodology for probabilistic density calculations.
• Incorporated relativistic effects to adjust lengths, densities, and moment of inertia.
• Applied the model to data from the neutron star PSR J0737-3039A.

Main Results:

• Density models were generated for PSR J0737-3039A with varying moment of inertia (MOI) values.
• Lower MOI values (e.g., f=0.258) resulted in higher core densities, exceeding 4x10^15 gm/cc.
• Calculated densities showed reasonable agreement with existing neutron star models but high sensitivity to MOI.

Conclusions:

• The MRE methodology provides a probabilistic framework for neutron star density modeling.
• Neutron star core densities are highly sensitive to assumed moment of inertia values.
• Future internal density models must satisfy constraints on averaged density and moment of inertia.