Science

The oldest star in the Milky Way is a white red dwarf.

At 10.7 billion years old, the oldest of our galaxy, the Milky Way. This is a white dwarf, located 90 light years from Earth, which was observed using the Gaia space telescope. It was identified by astronomers at the University of Warwick in England, scientists who seem to have specialized in finding stars with unusual characteristics. Before that, a white dwarf was indeed discovered, engaged in a frenzied rotation on itself, and even earlier – the most massive of the stars of this category.

Two grandmothers of the Milky Way

Moreover, white dwarfs are not stars in the classical sense of the term. They do not glow, but are very hot and cool very slowly over billions of years. They represent the last phase of the evolution of stars, the mass of which does not exceed the mass of the Sun by 10 times. After using up all their fuel, they over-inflate and eventually explode, forming a planetary nebula. At its center is a white dwarf, the open core of an ancient star. This is now roughly the size of the Earth for a mass similar to that of the Sun. During this process, the possible planetary system around the original star is largely destroyed, and then planetary debris accumulates on the surface of the white dwarf.

In fact, these are two stars of this type, which are reported in a publication published in the Monthly Notices of the Royal Astronomical Society. One is exceptionally blue, while the other is the coldest and most reddish one found to date in our galactic neighborhood. The last one, WDJ2147-4035, is the oldest at 10.7 billion years old and became a white dwarf 10.2 billion years ago. Since then, it has cooled very slowly given its initial heat and small surface area, which severely limits the amount of heat it can remove through heat transfer. Another star, WDJ1922+0233, is slightly younger. To determine their age, astronomers used spectroscopic and photometric data from GAIA, dark energy research, and the European Southern Observatory’s X-Shooter instrument.

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