Is the neutron star made up of?

A neutron star is not composed solely of neutrons, although neutrons make up the majority of its mass. Here are the key components:

Neutrons

Neutron stars are primarily made up of neutrons, which form the bulk of their mass. This is because the intense gravitational collapse of the star's core causes protons and electrons to combine into neutrons through beta decay25.

Protons and Electrons

In addition to neutrons, neutron stars also contain a smaller percentage of protons and electrons. These charged particles are necessary to maintain charge neutrality and are estimated to be around 10% each of the number of neutrons13.

Surface and Crust

The surface of a neutron star has a thin crust, which may be composed of ordinary atomic nuclei, such as iron, and a sea of free electrons. This crust is solid and can be subject to stresses that lead to starquakes4.

Core

The core of a neutron star is less well understood and could include various forms of dense matter, such as superfluid neutrons, and possibly more exotic particles like those with strange quarks or kaon condensates23.

In summary, while neutrons are the dominant component, neutron stars also contain protons, electrons, and possibly other exotic particles, with a solid crust on the surface.