White Dwarfs Reveal New Clues About Nature of Dark Photons

White dwarfs have revealed new clues when it comes to the nature of dark photons, a type of dark matter and energy. Researchers have been able to rule out a multitude of possible parameters for these photons, thanks to the shining of these dying stars.

White dwarfs represent the final life stage of stars with small or medium masses--less than a tenth of the mass of the Sun. Measuring the luminosity of these bodies allows astronomers to follow their cooling and the behavior of their particles in accordance with the standard model used in physics. Any diversion from predicted data should give researchers clues when it comes to dark matter and energy.

"The cooling rate of white dwarfs can be measured, even in real time, if we accept as such observations made over the course of 30 years," said Jordi Isern from the Institute of Space Sciences in a news release. "The presence in their interior of any extra energy source or drain would disrupt this cooling rate, enabling us to discover its presence."

In order to examine dark matter and energy, the researchers turned to white dwarfs and studied their brightness. In particular, they focused on the values between which dark photons can fluctuate. These hypothetical particles, related to the "dark" version of electromagnetism, can only be detected indirectly when they were broken down into electrons and antielectrons (positrons).

"Many of the attempts to expand the standard model are based on introducing new interactions which use dark photons as mediators, which, if they exist, can be created inside white dwarfs and escape freely, behaving as an energy drain which disrupts the development of the star," said Isern in a news release.

What did the researchers find? They discovered that in order to study other hypothetical particles beyond the standard model, such as neutralinos in supersymmetry models, Earth-based laboratories like CERN are still superior. That said, white dwarfs still provide interesting data. They have the capacity to give information about the past history of galaxies in addition to other data.

The findings are published in the journal Physical Review D.