Astrophysics from Italy using the Hubble telescope found evidence that the surfaces of some white dwarfs occur thermonuclear reactions. This process leads to a “slowdown” of their aging. The article of scientists was published in the journal Nature Astronomy.
Usually white dwarfs are gradually cooled compact stars in the last stages of their lives, luminous by the light of thermal radiation. To study their evolution, researchers from the Bologna University with the help of a Hubble wide-angle chamber were observed for 702 white dwarfs in two ball star clusters – M3 and M13, similar to age and metropolitanity (content of elements heavier than helium and hydrogen), but various in fact stars, which become white dwarfs.
284 white dwarfs from M3 turned out to be completely “ordinary”, while in M13 two populations were found: “ordinary” and those that managed to keep the outer layer of hydrogen, thereby slowing down the pace of its cooling. A comparison with the model of the proposed star evolution in M13 showed that about 70 percent of white dwarfs in the cluster on the surface, thermonuclear reactions occur.
Since, due to the predictability of the cooling process, white dwarfs were used as “star clock”, the opening can lead to the revision of the age of stellar clusters. Inaccuracy, according to scientists, may be up to a billion years.