While the solar system’s moons such as Europa and Enceladus have thin crusts over deep oceans, Mercury has a thin crust over a large metallic core. Thin sheets are generally likely to wrinkle. Europa has linear features, Enceladus has “tiger stripes” and Mercury has foliated cliffs. Neutron stars may have similar characteristics. These neutron star mountains can generate detectable oscillations in space and time known as gravitational waves, according to a new study.
Artist’s impression of a neutron star. Image credit: Sci.News.
Neutron stars are a trillion times denser than lead, and their surface features are largely unknown.
Nuclear theorists investigated the mountain-building mechanisms active on the moons and planets of the solar system.
Some of these mechanisms suggest that neutron stars likely have mountains.
A mountain in a neutron star would be much more massive than any mountain on Earth. They are so huge that the gravitational pull from these mountains alone can generate gravitational waves.
of Laser interferometer Gravitational wave observatory (LIGO) is currently looking for these signals.
“These waves are so weak that they require highly detailed and sensitive techniques carefully tuned to the expected frequencies and other signal characteristics,” said nuclear astrophysicist Jorge Morales and professor Charles Horowitz at Indiana University. It can only be discovered through search.”
“The first detection of continuous gravitational waves opens a new window on the universe and will provide unique information about neutron stars, the densest objects after black holes.”
“These signals may also provide sensitive tests of fundamental laws of nature.”
The authors investigated the similarities between neutron star mountains and surface features of solar system objects.
“While both neutron stars and certain moons, such as Jupiter’s moon Europa and Saturn’s moon Enceladus, have a thin crust over a deep ocean, Mercury has a thin crust over a large metallic core. The thin sheet Wrinkles are universally possible,” they said.
“Europa has linear features, Enceladus has tiger-like stripes, and Mercury has curved, step-like structures.”
“Mountained neutron stars may have similar types of surface features that can be discovered by observing continuous gravitational wave signals.”
“Earth’s innermost core is anisotropic, and its shear modulus is direction-dependent.”
“If the material in the neutron star’s crust is also anisotropic, a mountain-like deformation will occur, and its height will increase as the star rotates faster.”
“Such surface features could explain the maximum spin observed in neutron stars and the minimum possible deformation of radio-emitting neutron stars known as millisecond pulsars.”
team’s paper Published in a magazine Physical Review D.
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JA Morales and CJ Horowitz. 2024. The anisotropic neutron star crust, the mountains of the solar system, and gravitational waves. Physics. Rev.D 110, 044016; doi: 10.1103/PhysRevD.110.044016
Source: www.sci.news
