Rare White Dwarf Pulsar System Discovered by University of Warwick Research Group

A research team from the University of Warwick has made a groundbreaking discovery, finding a rare type of white dwarf pulsar system for only the second time ever. This discovery provides significant advancements in our understanding of stellar evolution and sheds light on the mysterious nature of these celestial objects.

White dwarfs are small, dense stars that form when a low-mass star has burned all its fuel and lost its outer layers. They are often referred to as “stellar fossils” because they offer valuable insights into the formation and evolution of stars.

The newly discovered white dwarf pulsar, named J1912-4410, is a burnt-out stellar remnant that spins rapidly, emitting intense beams of electrical particles and radiation at regular intervals. These powerful emissions are caused by the pulsar’s potent magnetic fields, which scientists theorize may originate from an internal dynamo, similar to Earth’s but much more powerful.

The existence of white dwarf pulsars and their strong magnetic fields have long puzzled scientists. To test the theory of the dynamo model, which suggests that white dwarfs have electrical generators in their core, researchers needed to find more examples of these systems.

Published in Nature Astronomy on June 15, the research team describes their discovery of J1912-4410, which is only the second known white dwarf pulsar system. The first one, called AR Scorpii (AR Sco), was discovered in 2016.

Located 773 light years away from Earth and spinning 300 times faster than our planet, J1912-4410 has a size similar to Earth but a mass at least as large as the Sun. This means that a teaspoon of white dwarf material would weigh around 15 tons. The low temperature of J1912-4410 indicates that it is an advanced-age star, as white dwarfs cool down over billions of years.

Dr. Ingrid Pelisoli from the University of Warwick’s Department of Physics explains that the discovery of J1912-4410 is a critical step forward in understanding the origin of magnetic fields in white dwarfs. The dynamo model, which suggests that these magnetic fields are more than a million times stronger than the Sun’s, helps explain their existence. The discovery of J1912-4410 confirms the predictions made by this model.

The research team used data from various surveys to identify potential candidates for white dwarf pulsars, focusing on systems with similar characteristics to AR Sco. They then used ULTRACAM, a tool that detects fast light variations, to observe these candidates. After observing several candidates, they found one that exhibited similar light variations to AR Sco. Further observations with other telescopes confirmed that this system emitted radio and X-ray signals in our direction every five minutes, confirming its status as a white dwarf pulsar.

Dr. Pelisoli’s research is supported by a £3.5 million private philanthropic donation from a Warwick alumnus, which is one of the largest gifts towards the study of astronomy and astrophysics in the UK. This donation is enabling the next generation of astronomers to explore the farthest reaches of our universe.

Axel Schwope from the Leibniz Institute for Astrophysics Potsdam (AIP), who is leading a complementary study published in Astronomy and Astrophysics, expressed excitement about independently finding the object in the X-ray all-sky survey. The follow-up investigation confirmed the pulsations in the high-energy X-ray regime, firmly establishing white dwarf pulsars as a new class of celestial objects.

This groundbreaking research not only provides valuable insights into stellar evolution but also demonstrates the power of scientific predictions and testing. The discovery of J1912-4410 and its confirmation of the dynamo model theory pave the way for further exploration and understanding of white dwarf pulsar systems.

Reference:
“A 5.3-min-period pulsing white dwarf in a binary detected from radio to X-rays” by Ingrid Pelisoli, T. R. Marsh, David A. H. Buckley, I. Heywood, Stephen. B. Potter, Axel Schwope, Jaco Brink, Annie Standke, P. A. Woudt, S. G. Parsons, M. J. Green, S. O. Kepler, James Munday, A. D. Romero, E. Breedt, A. J. Brown, V. S. Dhillon, M. J. Dyer, P. Kerry, S. P. Littlefair, D. I. Sahman, and J. F. Wild, 15 June 2023, Nature Astronomy.
DOI: 10.1038/s41550-023-01995-x

What are the implications of the confirmation of periodic pulsations in the white dwarf pulsar system J1912-4410 for the dynamo model and our understanding of stellar evolution

, a high-speed camera system, to observe and analyze the light emitted by these candidates. This allowed them to confirm the presence of periodic pulsations, indicating the presence of a white dwarf pulsar system.

The discovery of J1912-4410 and its confirmation of the dynamo model is a significant breakthrough in the field of astrophysics. It provides further evidence for the existence and nature of white dwarf pulsars and expands our understanding of stellar evolution. This discovery opens up new avenues of research into the magnetic fields of white dwarfs and their role in the evolution of these celestial objects.

Moving forward, the research team plans to continue studying white dwarf pulsars in order to gain a better understanding of their properties and to further test the dynamo model. By studying these rare systems, scientists hope to unravel the mysteries of stellar evolution and gain insights into the formation and behavior of stars.

In conclusion, the discovery of J1912-4410, a rare white dwarf pulsar system, by the research team from the University of Warwick is a groundbreaking achievement in the field of astrophysics. This discovery provides significant advancements in our understanding of stellar evolution and sheds light on the mysterious nature of these celestial objects. Further research and study of white dwarf pulsars will undoubtedly reveal more about the magnetic fields and properties of these fascinating systems.