A dead star turns on herself at a crazy speed … and hides a secret that scientists have just pierced. Thanks to a space telescope, NASA has observed a phenomenon never seen before.
Dead stars have been fascinating astronomers for a long time. In 2024, an ultra-magnetic star had issued a powerful radio start, a rare phenomenon that helps scientists explore the universe and even detect dark matter. These stars, called neutron stars, are real cosmic laboratories. Today, a new observation sheds light on another type of star of this kind: a pulsar, and more precisely a “pulsar millisecond”, which turns hundreds of times per second.
In a study published in The Astrophysical Journal Letters, researchers describe a pulsar named PSR J1023+0038. This star is part of a binary system where it regularly absorbs material from a small neighboring star. It alternates between an “active” phase and a “calm” phase, a rare behavior which makes it a precious object of study. To analyze it, the team has combined the data from several instruments: the NASA X IXPE X-IXPE telescope, an optical telescope in Chile (VLT), and a network of radio stakes in the United States (VLA).
Pulsar J1023 reveals a polarization record which reveals the real origin of its radiation
During observations, The researchers noticed that the radiation of this star did not really come from the suckled matter. In reality, it is caused by a very rapid particle wind, projected by the pulsar. The latter strikes the material around the star, which creates intense radiation. Thanks to IXPE, the researchers discovered that 12 % of the X -rated X -rays are polarized, a figure never observed in a system of this type. To put it simply: it is as if the light emitted had a precise orientation, a bit like through polarized glasses.
The researchers also measured the polarization of radio waves and visible light emitted by the pulsar. Even if these two signals have a lower polarization (2 % for radio waves, 1 % for visible light), their orientation is exactly the same as that observed for X -rays. This indicates that These different forms of radiation have a common origin: the wind of highly energetic particles expelled by the pulsar.
These results confirm a major hypothesis according to which this wind hits the material in orbit around the star (the accretion disc), thus creating polarized radiation. This phenomenon allows scientists to better understand how energy spreads around active pulsars, and gives new tools to study their complex environment. This advance also offers a concrete way to test the theoretical models linked to the extreme physics of these dead stars.
