* Neutron stars are incredibly dense. They are the collapsed cores of massive stars, packing the mass of our sun into a sphere only a few miles across. This extreme density creates a very strong gravitational pull.
* Companion stars are often smaller and less massive. They can be normal stars, white dwarfs, or even other neutron stars.
* The gravitational pull of the neutron star dominates the system. This causes the companion star to orbit the neutron star in a tight spiral.
* The orbit can be very close. Depending on the masses of the stars and the initial conditions of the system, the companion star can be very close to the neutron star, almost touching its surface.
Important Note: The companion star's material is not "wrapping around" the neutron star in a physical sense. The strong gravity pulls material from the companion star onto the neutron star, forming an accretion disk.
Here's how it works:
1. The neutron star's gravity pulls material from the companion star. This material is typically from the companion star's outer layers, where the gravity is weaker.
2. The material forms an accretion disk around the neutron star. This disk is a swirling ring of gas and dust, heated to extremely high temperatures by friction and the neutron star's magnetic field.
3. The material spirals inward towards the neutron star. As it falls towards the neutron star, it gains energy and momentum, eventually crashing onto its surface.
4. This accretion process releases enormous amounts of energy. This energy is emitted as X-rays and gamma rays, making these systems incredibly bright and detectable from Earth.
So, it's not wrapping around, but rather a constant flow of material from the companion star onto the neutron star driven by the intense gravity of the neutron star.
