Anna Hartz
Astronomy often moves forward in small steps. Then, from time to time, something appears in the sky that simply does not fit the rules.
These moments force scientists to rethink what they thought they knew about how stars behave. A recent discovery involving a distant stellar system is one of those moments.
Should Not Exist
The object at the center of the discovery is called RXJ0528+2838, writes WP. It sits about 730 light-years away from Earth. The system contains a white dwarf, which is the dense remains of a star similar to our Sun, and a companion star that closely resembles the Sun itself.
Astronomers studying this pair noticed something unexpected. A large shockwave surrounds the system, forming a clear arc in space. According to existing theories, this structure should not exist there.
The surprise did not stop there. The shockwave is linked to an outflow, meaning material is being pushed away from the system. In most binary systems like this one, gas flows from the companion star into a spinning accretion disk around the white dwarf. That disk usually drives any outflow. In this case, no such disk was found.
Simone Scaringi from Durham University said the finding caught the team completely off guard. Krystian Iłkiewicz from the Copernicus Astronomical Centre in Warsaw agreed. He explained that, based on current understanding, this type of outflow should not happen without an accretion disk.
A Strong Magnetic Field
The size and shape of the shockwave suggest that material has been escaping from the system for at least a thousand years. Data from the MUSE instrument on the Very Large Telescope showed that the glowing gas comes from the binary system itself and not from a nearby cloud of gas. A crucial detail emerged during the analysis. The white dwarf has an extremely strong magnetic field.
Researchers now believe this magnetic field is the key. Instead of forming a disk, material pulled from the companion star is guided directly onto the surface of the white dwarf. From there, part of it is pushed back into space. This proves that accretion disks are not always needed for matter to escape from such systems.
The magnetic field does not explain everything. It may not be strong enough to account for how long the shockwave has existed. Scientists plan to study similar systems and use more powerful telescopes in the future. Their goal is to understand how many other stars are breaking the rules in the same way.
Sources: WP
