Scientists at the University of Warwick have made an exciting discovery that provides new insights into the evolution of stars.
They have found a rare type of white dwarf star system, offering a unique glimpse into the life cycle of these fascinating celestial objects.
White dwarfs are compact stars, typically about the size of a planet, which form when low-mass stars exhaust their fuel and shed their outer layers.
These “stellar fossils” hold valuable information about star formation and evolution.
In this recent study published in Nature Astronomy, researchers describe a white dwarf pulsar called J1912-4410. It is only the second star system of its kind ever found, following the discovery of AR Scorpii in 2016.
Located approximately 773 light years away from Earth, J1912-4410 spins at an incredible rate—300 times faster than our planet.
Although it has a size similar to Earth, its mass is at least as large as the Sun. To put this into perspective, just a teaspoon of material from this white dwarf would weigh around 15 tons. J1912-4410’s relatively low temperature suggests it is quite old.
The magnetic fields of white dwarfs, including pulsars, are extremely strong—more than a million times stronger than the Sun’s magnetic field.
However, scientists have been uncertain about what causes these intense magnetic fields.
One theory, known as the “dynamo model,” suggests that white dwarfs have powerful electrical generators called dynamos in their cores, similar to Earth but much stronger.
To test this theory, scientists needed to find more white dwarf pulsars. By analyzing data from various surveys and using a specialized instrument called ULTRACAM, researchers identified J1912-4410 as a promising candidate.
Further observations with other telescopes confirmed that this system emits radio and X-ray signals towards Earth approximately every five minutes.
The discovery of J1912-4410 validated several predictions made by the dynamo model.
Its old age and cool temperature align with expectations, as do the fast spinning of the companion star and the strong gravitational interaction between the white dwarf and its companion.
Dr. Ingrid Pelisoli from the University of Warwick emphasized the importance of this discovery in understanding the origins of magnetic fields. By confirming the existence of more white dwarf pulsars, scientists can make and test predictions, advancing our knowledge of this fascinating field.
Another research team led by Axel Schwope from the Leibniz Institute for Astrophysics Potsdam conducted a complementary study using X-ray surveys. They independently detected J1912-4410, confirming its unusual nature and establishing white dwarf pulsars as a new class of celestial objects.
This groundbreaking research not only provides valuable insights into the magnetic fields of white dwarfs but also demonstrates the power of scientific discovery.
By making predictions and putting them to the test, scientists push the boundaries of knowledge and drive the progress of science as a whole.
The study was published in Nature Astronomy.
