Surprising astronomers, a strange, dead magnetic star has a solid surface

 By Troy Farah

Updated Jan 09, 2023 2:59 PM (EST)

The unusual neutron star 4U 0142+61 is surrounded by a massive ring of matter and has a solid surface.

The most extreme occurrences in the cosmos are neutron stars, and fresh information about these dense stellar corpses continues to astound astronomers. Recently, astronomers reported finding a magnetic neutron star with what seems to be a fully solid surface. Due to their incredible density, neutron stars are typically undulations of supercompressed solid matter (mostly neutrons), with a core that is a type of frictionless fluid known as a superfluid. In contrast, stars are typically made of hot orbs of plasma, an ionised gas. They frequently have atmospheres, just as Earth. It's fairly unusual to think of a neutron star as being entirely solid, similar to a highly dense planet without an atmosphere.

An international group of 50 researchers used information from the Imaging X-ray Polarimetry Explorer (IXPE), a satellite that NASA and the Italian Space Agency launched in December 2021. Their findings were published in the journal Science. The researchers collected data on the neutron star with the oblique designation 4U 0142+61. A magnetar is a particular kind of neutron star that is around 13,000 light years away from Earth in the Cassiopeia constellation.

Essentially, a magnetar is a neutron star with an extraordinarily powerful magnetic field. There are only around 30 that we are aware of, most likely because they are difficult to locate. They are tiny and dim, and are only seen when there is an increase in activity, such as when they emit enough high-energy electromagnetic radiation (think gamma rays or X-rays), which is otherwise difficult to see from Earth.