They observe, for the first time, a star with a solid surface and no atmosphere

Led by Roberto Taverna of the University of Padua in Italy, an international team of more than 50 researchers has discovered something fascinating: a magnetar with a solid surface and no atmosphere. Magnetars are stellar corpses, compact cores of stars with a powerful magnetic field. The researchers, whose work has been published in Science, made their finding by studying for the first time the polarized X-ray light emitted by a magnetar, something they did with NASA’s X-ray Polarimetry Imaging Explorer (IXPE). ). The IXPE collaboration between NASA and the Italian Space Agency allows scientists to examine X-ray light in space by measuring its polarization, that is, the direction in which the light waves oscillate. Thus, the team studied magnetar 4U 0142+61, located in the constellation Cassiopeia, approximately 13,000 light-years from Earth. Dead stars As is well known, magnetars are a type of neutron star: very dense cores, remnants of massive stars that exploded as supernovae at the end of their lives. But unlike other neutron stars, magnetars have a huge magnetic field, among the most powerful in the Universe. They emit brilliant X-rays and display erratic periods of activity, emitting bursts and flares that can release millions of times more energy in just one second than our Sun emits in an entire year. It is believed that these impressive energetic emissions are fueled precisely by their enormous magnetic fields, between 100 and 1,000 times stronger than those of standard neutron stars. In their study of 4U 0142+61, the researchers found a much lower proportion of polarized light than would be expected if X-rays passed through an atmosphere. Polarized light is light in which the movement occurs all in the same direction, that is, the electric fields vibrate only in one way. An atmosphere acts like a filter, selecting only one state of polarization of light. Taverna and his team also found that for light particles at higher energies, the polarization angle was reversed by exactly 90 degrees compared to light at lower energies, following what theoretical models would show if the star had a solid crust. surrounded by an external magnetosphere filled with electrical currents. An unexpected finding According to Silvia Zane, co-author of the article, “This was something totally unexpected. I was convinced that there would be an atmosphere. But here the star’s gas has reached a tipping point and has turned solid in a similar way that water might turn to ice. This is the result of the star’s incredibly strong magnetic field.” For Taverna, “the most exciting feature we were able to observe was the change in the polarization direction, with the angle of polarization oscillating exactly 90 degrees. This agrees with what theoretical models predict and confirms that magnetars are endowed with ultra-strong magnetic fields.” Quantum theory, in effect, predicts that light propagated in a strongly magnetized environment is polarized in two directions, parallel and perpendicular to the magnetic field. The amount and direction of the observed polarization is imprinted on the structure of the magnetic field and the physical state of matter in the vicinity of the neutron star, providing information that would otherwise be inaccessible. MORE INFORMATION noticia No US and Russia plan how to rescue astronauts trapped in the space station “in case of emergency” noticia No Why bacteria from the past are key to curing genetic diseases of the present Scientists think that the crust The star’s solid is composed of a lattice of ions, held together by the strong magnetic field. The atoms would not be spherical but elongated in the direction of that field. The question of whether or not magnetars and other neutron stars have an atmosphere is still up for debate, but this new work, with the first reliable detection of a solid crust in a magnetar, has tipped the balance.