White dwarfs are fascinating remnants of stars that have burned out. Usually, they sit quietly in space, but some have been spotted racing through our galaxy at incredible speeds—up to 1,240 miles per second! That’s fast enough to travel from New York to Los Angeles in just two seconds.
These speedsters, known as hypervelocity white dwarfs, have puzzled scientists since their discovery in 2018. The extreme speeds hint at explosive events but haven’t been fully explained—until now. A recent study led by Hila Glanz from the Technion-Israel Institute of Technology may provide some answers.
Using advanced simulations, Glanz and her team examined what happens when two white dwarfs merge. Glanz described their approach like piecing together a puzzle, aiming to clarify this cosmic mystery. Their findings, published in *Nature Astronomy*, not only matched the observed high speeds of these stars but also explained their unusual, heated appearances.
The researchers focused on a merger of hybrid white dwarfs—stars with carbon-oxygen cores and shells of helium. In the simulation, the lighter star gets pulled in and torn apart by its heavier partner. The resulting intense heat from friction leads to a powerful explosion that sends the lighter star shooting away at high speeds.
This type of explosion, a thermonuclear supernova, doesn’t leave many remnants behind, which aligns with the observed nature of hypervelocity white dwarfs. The previous D6 theory, which suggested a massive white dwarf exploding with minimal mass transfer, couldn’t explain both the speeds and the puffed-up appearances of these stars.
Glanz’s new model shows that even lighter stars can become hypervelocity objects if the right conditions occur during a merger. The results reveal that a variety of cosmic events might create hypervelocity white dwarfs, rather than only one specific process. This insight could help scientists understand more about Type Ia supernovae, which are bright explosions that help measure cosmic distances and produce essential elements like iron.
The excitement doesn’t stop here. Future sky surveys, such as those from the Vera C. Rubin Observatory, might catch these events live, providing more clues about these stellar phenomena. “We’re still piecing together the puzzle,” Glanz notes, highlighting the ongoing mystery of our universe.
For more on stellar explosions and cosmic discoveries, you can check out this [NASA report](https://www.nasa.gov/) for the latest updates.