A second discovery of an elusive type of white dwarf pulsar system has been made by a research team, signifying a substantial leap in our understanding of star development. The pulsar, tagged as J1912-4410, rotates at high speed, projecting strong beams of electric particles and radiation consistently due to its robust magnetic fields. Scientists speculate that these fields could stem from an internal dynamo, similar but far superior to Earth’s. Credit: Dr. Mark Garlick//University of Warwick.
A group of researchers from the University of Warwick has unearthed a scarce white dwarf pulsar for the second time, shedding light on stellar evolution. The pulsar’s notable magnetic fields, swift rotation, and lower temperature are supportive of the dynamo model theory and imply the star’s maturity, further affirming the existence of similar systems.
This discovery of a unique white dwarf star system provides fresh insights into stellar evolution.
White dwarfs, often referred to as “stellar fossils,” are small, dense stars about the size of a planet. These are the remnants of low mass stars that have exhausted their fuel supply and lost their external layers, offering valuable information on star formation and evolution.
A rare white dwarf pulsar has been unearthed for just the second time by the University of Warwick-led research. White dwarf pulsars are a type of star system that includes a rapidly spinning white dwarf that bombards its neighboring red dwarf with potent beams of electric particles and radiation. This process causes the system to repeatedly brighten and fade significantly, attributed to strong magnetic fields. However, the origins of these fields remain a mystery to scientists.
The “dynamo model” is a prevalent theory to elucidate the strong magnetic fields – it proposes that white dwarfs contain electrical generators (dynamos) in their core, much like Earth, but exponentially more potent. However, to confirm this theory, scientists need to find other white dwarf pulsars to corroborate their predictions.
Illustration of a white dwarf, a solid crystalline-core remnant of a star akin to our Sun. Credit: University of Warwick/Mark Garlick.
In the Nature Astronomy publication dated June 15, UK Science and Technology Facilities Council (STFC)-funded scientists detail the newly discovered white dwarf pulsar, J191213.72-441045.1 (J1912-4410). It is the second time such a star system has been discovered since AR Scorpii (AR Sco) in 2016.
Positioned 773 light years from Earth and spinning 300 times faster than our planet, the white dwarf pulsar is about the size of Earth, but its mass equals or surpasses the Sun’s. Consequently, a teaspoon of white dwarf material would weigh around 15 tons. White dwarfs initially have extremely high temperatures that cool over billions of years, and the low temperature of J1912−4410 indicates a significant age.
Dr. Ingrid Pelisoli from the University of Warwick’s Physics Department said, “The origin of magnetic fields is a major unresolved question in many astronomy fields, particularly for white dwarf stars. The magnetic fields in white dwarfs can exceed the magnetic field of the Sun by over a million times, and the dynamo model assists in explaining why. The discovery of J1912−4410 represents a vital progression in this field.
We sourced data from several surveys for potential candidates, concentrating on systems with characteristics similar to AR Sco. Candidates were followed up with ULTRACAM, which detects the rapid light variations typical of white dwarf pulsars. After examining a couple of dozen candidates, we found one that exhibited light variations analogous to AR Sco. Our additional observation campaign with other telescopes unveiled that this
Frequently Asked Questions (FAQs) about white dwarf pulsar
What is a white dwarf pulsar?
A white dwarf pulsar is a type of star system consisting of a rapidly spinning white dwarf star that emits powerful beams of electrical particles and radiation, causing the system to periodically brighten and fade.
How does the discovery of a white dwarf pulsar contribute to our understanding of stellar evolution?
The discovery of a white dwarf pulsar provides valuable insights into stellar evolution. By studying these systems, scientists can investigate the mechanisms behind magnetic fields, the aging process of white dwarfs, and the dynamics of stellar companions.
What is the dynamo model in relation to white dwarf pulsars?
The dynamo model is a theory that suggests white dwarfs possess electrical generators (dynamos) in their core, similar to Earth but much more powerful. This model helps explain the strong magnetic fields observed in white dwarf pulsars.
Why are white dwarfs referred to as “stellar fossils”?
White dwarfs are often called “stellar fossils” because they are the remnants of low mass stars that have depleted their fuel and shed their outer layers. They provide valuable insights into different aspects of star formation, evolution, and the eventual fate of stars like our Sun.
How does the discovery of J1912-4410 contribute to the dynamo model theory?
The discovery of J1912-4410, a white dwarf pulsar, supports the predictions of the dynamo model. The system’s advanced age, cool temperature, and fast rotation align with the expectations of the model, confirming its validity to explain magnetic fields in white dwarfs.
What are the implications of finding more white dwarf pulsars?
The discovery of additional white dwarf pulsars confirms the existence of these systems, further validating the dynamo model and expanding our understanding of magnetic fields in white dwarfs. It allows scientists to test and refine their theories about stellar evolution and magnetic processes in these compact stellar remnants.
More about white dwarf pulsar
- Nature Astronomy: A 5.3-min-period pulsing white dwarf in a binary detected from radio to X-rays
- University of Warwick: New White Dwarf Pulsar Discovery: “Stellar Fossils” Unveil Cosmic Secrets
- Science and Technology Facilities Council (STFC)
- Astronomy and Astrophysics: Complementary study on the white dwarf pulsar
- Leibniz Institute for Astrophysics Potsdam (AIP)