A new theory suggests how white dwarf stars can avoid collapsing into a black hole.

In a groundbreaking study published in the prestigious journal Nature, researchers from the Institute for Advanced Study, the University of Victoria in Canada, and the University of Warwick in the U.K. have unveiled a new theory that sheds light on the mysterious phenomenon of certain white dwarf stars defying the expected cooling process for billions of years.

Traditionally, white dwarf stars have been regarded as "dead stars" that gradually cool down over time as they exhaust their nuclear heat source. This cooling process leads to the solidification of the dense plasma within the star from the inside out. However, recent observations from the European Space Agency's Gaia satellite, analyzed by Sihao Cheng, challenged this conventional understanding by revealing that some white dwarfs remain unusually hot for extended periods, defying the expected cooling pattern.

The collaborative research team, which included Cheng, Antoine Bédard, and Simon Blouin, proposed a novel explanation for this phenomenon. They suggest that in certain white dwarfs, rather than freezing uniformly from the inside, the solid crystals formed during the cooling process are less dense than the liquid plasma and start to float towards the surface. As these crystals ascend, they displace the heavier liquid downwards, leading to the release of gravitational energy that effectively interrupts the star's cooling process for billions of years.

This intriguing mechanism, resembling the behavior of ice cubes floating in water, highlights the complex interplay of density variations within the white dwarf stars. The researchers speculate that the composition of the star, particularly those formed through the merger of different stars, plays a crucial role in allowing the formation of these floating crystals.

The implications of this discovery are profound, as it challenges existing assumptions about the ages of white dwarf stars and their use as age indicators in astronomical studies. By demonstrating that some white dwarfs exhibit delayed cooling, the research suggests that these stars may be significantly older than previously estimated, prompting a reevaluation of age calculations for stellar populations.

The study, supported by various research grants and fellowships, represents a significant advancement in our understanding of white dwarf stars and their evolution. The findings not only offer new insights into the complex processes governing these celestial bodies but also have implications for broader astronomical studies, including the reconstruction of the formation history of our galaxy.

This groundbreaking research underscores the importance of continued exploration and discovery in the field of astrophysics, pushing the boundaries of our knowledge and challenging established scientific paradigms.

Source: https://www.eurekalert.org/news-releases/1036815