White dwarfs continue to amaze astronomers and teach us all that there is so much more to learn about these objects. Astronomy is an incredibly vast field, and when it comes to white dwarfs, dozens of books can be written.
White dwarfs are incredible mainly for their tremendous gravity. The gravity of these cosmic objects is 350,000 times that of Earth. You can easily guess that going anywhere near a white dwarf would be a terrible idea – you would be instantly crushed if you are too close.
Stable thermonuclear activity affects white dwarfs
According to Phys.org, scientists finally found evidence that white dwarfs are capable of slowing down their own rate of aging by the method of burning hydrogen at the surface.
For the new study, the scientists compared cooling white dwarfs in two collections of stars, meaning the globular clusters known as M3 and M13. Astronomers used the Hubble observations to obtain an accurate contrast for how stars can evolve in M3 and M13. Taking advantage of the Wide Field Camera 3 of the Hubble Telescope, the team of astronomers was able to observe M3 and M13 at almost ultraviolet wavelengths. This allowed them to compare over 700 white dwarfs in the two clusters.
The conclusion was that M13 contains two populations of white dwarfs, and one of them managed to keep an outer envelope of hydrogen, thus assuring them a longer period of burning.
Jianxing Chen, leader of the new research who works at the Alma Mater Studiorum Università di Bologna and also at the Italian National Institute for Astrophysics, declared as cited by Phys.org:
We have found the first observational evidence that white dwarfs can still undergo stable thermonuclear activity,
This was quite a surprise, as it is at odds with what is commonly believed.
It’s also known about white dwarfs that many of them will become black dwarfs, and they can even go supernova.
The new study was published in Nature Astronomy.