“Mountains” on neutron stars can create ripples in space-time

Scientists have found that mountains on the surface of neutron stars can create gravitational waves. Their study can provide unique information about the internal structure of these objects.

A neutron star in an artist’s impression. Source: ESA

Neutron stars are the remnants of collapsed luminaries. They are among the densest objects in the Universe, a trillion times denser than lead. With a diameter of a few tens of kilometers, the mass of a neutron star can be comparable to that of the Sun.

Previous studies have shown that the surface of a neutron star can have irregularities. Although the height of these “mountains” is measured in millimeters, they must have enormous mass.

In a new study, scientists from Indiana University and the Max Planck Society’s Institute for Gravitational Physics have concluded that neutron stars may have similarities to moons of giant planets such as Europa and Enceladus, whose icy surfaces hide vast oceans of liquid water beneath their icy surfaces. In the case of neutron stars, its role is played by superfluid neutron liquid.

Given this similarity, scientists hypothesize the presence of deformations on the surface of neutron stars, similar to the “tiger stripes” observed at the south pole of Enceladus. They must have enough mass to warp space-time, generating gravitational waves.

The gravity of mountains on rapidly rotating neutron stars causes ripples in space-time known as gravitational waves. The Laser Interferometer Gravitational-Wave Observatory (LIGO) is searching for such waves. Source: Charles Horowitz

According to the researchers, these waves are extremely weak, but they can be registered by LIGO. If discovered, they will provide unique information about the structure of neutron stars.

Previously, we described how axions could form clouds around neutron stars.

According to Phys.org

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