New type of star may explain the origin of magnetars


The universe presents an innumerable number of extremely interesting events and phenomena. From incredible visual displays such as images of galaxies and nebulae, to curious objects such as black holes. While these are the ultimate expression of the power of having an enormous amount of mass, the so-called magnetars have magnetic fields millions of times more powerful than any artificial magnet produced in laboratories. A new type of star discovered offers new light on the process or conditions that give rise to this strange object.

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Artist's impression of the star HD 45166, in which a strong magnetic field was recently discovered that may generate a magnetar in the future.

Stellar death

Stars require constant fusion of light elements in their core to maintain a balance between radiation pressure and gravity. Once it has consumed a large part of its fuel, it will have a mass-dependent end. In the case of being low, it will expel the outer layers, leaving a white dwarf in its core, if it were very large it would detonate as a supernova and form a black hole. However, in between these two scenarios is the possibility of leaving a remnant known as a neutron star.

Neutron stars are astrophysical objects of very high density and with enormous spin velocities. Some of them can emit jets of particles or beams of light and become pulsars. But in 10 % of the cases the conditions, still unknown, are given to give way to magnets. Which are the most powerful magnets that have been detected, reaching in the order of one hundred trillion Gauss.

A dying star

Using numerous observatories across the globe, a team of researchers studied the enigmatic star HD 45166. It belongs to a binary system and so far it was not possible to explain its behavior with conventional models.. More than one hundred years of observation have allowed us to estimate its mass at approximately twice that of the Sun and it has an abundance of helium, after having expelled its outer layers of hydrogen.. It is believed to have been formed by the merger of two other helium-rich stars.

 Using different instruments they were able to determine the existence of a magnetic field produced by the star and it was estimated at about four thousand three hundred Gauss. This makes HD 45166 the most magnetic object of its kind found to date. For reference, that of the Earth at its surface is only half a Gauss.

This is also the first discovery of a helium-rich magnetic star.. And it promises to provide new key information about the formation of magnetars. Which may appear when a star similar to HD 45166 dies and leaves in its place a neutron star with about a billion times its magnetic field after collapsing under its own gravity.

Understanding the universe

HD 45166 is a candidate for a future magnetar, however, when compared to the others already formed there is a clear difference. All are isolated, so the star is expected to lose its orbital companion. As well as going from a rotation period of one hundred and twenty-five days to forty milliseconds or less. It is necessary to find other similar objects to reinforce the proposed model.

Francisco Andrés Forero Daza