Thousands of stars, including our Sun, will turn into huge crystals
With data collected with the ESA-owned Gaia probe, British scientists have provided the first direct evidence that white dwarfs, the dead remnants of stars similar in size to our Sun, are turning into huge crystals. The researchers’ findings could change the way we calculate the age of some of the oldest objects in the Universe.
Most stars entering the final chapter of their lives tend to shrink, diminish and slowly change color. Astronomers determine these cold, dense objects ktore once powerful stars, they are called white dwarfsow.
These objects are the remnants of medium-sized stars similar to our Sun. When they use up all their fuel in the nucleus and shed their outer layers, the remaining still hot nucleus will begin to cool down. This process can take billions of years.
These extremely dense stellar remnants still emit thermal radiation and are therefore visible to astronomersow. It is estimated that up to 97 percent of stars in the Milky Way will eventually turn into white dwarfs, including our Sun. In contrast, the most massive stars will end their lives as neutron stars or black holes.
When the cooling process brings the star’s remnants to a certain temperature, the originally hot, liquid substance inside the star’s core will begin to crystallize and eventually become a hard solid. Scientists cfownali this process to liquid water turning into lod. With that said, the core solidification temperature in white dwarfs is extremely high, at around 10 millionoin degrees Celsius.
The results of the study by British scientistsoin the pages of the journal „Nature”.
The process of solidification or crystallization of material inside white dwarfsow was predicted 50 years ago, but only the capabilities of the Gaia probe allowed astronomers to observe enough of these objectsow with such accuracy as to see the pattern ofor revealing this entire process.
– Previously, we could only observe a few hundred white dwarfsow. Many of them were in clusters, in which theorych all objects have a similar age – admitted Pier-Emmanuel Tremblay of the University of Warwick, head of theoThe lead author of the publication. – Thanks to the Gaia observatory, we have the ability to observe at a much greater distance. We can see exactly hundreds of thousands of white dwarfsow w rodifferent stages of development – added.
In the study, astronomers analyzed more than 15,000 objectoin classified, as white dwarfs. All at a distance of up to 300 light years from Earth. In the observatory data, crystallizing white dwarfs were clearly visible, as a rather distinct group.
– All white dwarfs crystallize at some point in their evolution, although the more massive ones go through the process earlier. This means that billions of white dwarfsoin our galaxy have already completed this process and are essentially crystal spheres in the sky – explained Tremblay.
Confirmation of this model has some significant implications for determining the age of someor of the most common objectsoin the Milky Way. The heat released during the crystallization process appears to slow down the evolution of white dwarfsow, making them appear much younger than they actually are.
– White dwarfs are traditionally used to determine the age of stellar populations, such as star clusters and galactic halo, Tremblay explained. – We will now need to develop better crystallization models to get more accurate estimates of the age of these systemsow – added.
The researcher marked roAlso that not all white dwarfs crystallize at the same rate. More massive stars cool faster and reach temperatures at whichocruise follows crystallization in about a billion years. White dwarfs with lower masses, such as our Sun, cool more slowly, requiring about six billionoin years to turn into huge, crystalline structures.
Our Sun still has about five billion ahead of itow years before it becomes a white dwarf. Astronomers estimate it will pass another five billionoin years before it eventually cools down and becomes a crystal ball.