Why Our Sun Will Become White Dwarf In The Future

Once the mass-temperature threshold is exceeded, the star begins to merge hydrogen into helium and meets one of three different destinies. These fates are determined by the mass of the star, which in turn determines the maximum temperature that can be reached in the nucleus.

Stars with masses below the Chandrasekhar boundary, when they run out of fuel, become white dwarfs no matter when they are born. Whether a star becomes white dwarf depends on how much mass the red giant has lost in the early stages of evolution.

For stars that transform into white dwarfs despite a main sequence mass of more than 6m suns, stars with lower masses did not have time to consume all of their stored nuclear energy. Astronomers continue to look for suitable clusters to perform this test, but evidence suggests that stars with masses under 8m Sun have lost enough mass to end their white dwarf life. A star that turns into a white dwarf will lose 4.6 m of its mass, or less than 1.4 m sun, by the end of nuclear power generation.

White dwarfs are extremely dense, with masses similar to the suns, limited to a volume comparable to Earth (about one cubic centimeter) and weigh an incredible 1,000 kilograms. A star graveyard, a white dwarf nucleus, leaves behind a star that has exhausted its fuel supplies, like a gravestone on which a star lives and dies.

As for stellar evolution, decades of observations, combined with theoretical models, have enabled astronomers to use their classification to infer what is happening to a star. The location of the star furnace where new atoms are forged - the white dwarf nucleus left behind after a star runs out of fuel - has been reallocated by astronomers as a tool to turn our understanding of the evolution of the universe upside down. Artistic impression of star evolution: Depending on the classification, stars can become black holes, neutron stars or white dwarfs.

New observations published in the journal Nature show that most stars, including our sun, are transformed into huge space crystals the size of Earth, which are marked by spots in the solar system. The largest stars, the blue supergiants, pass over to supernova and become neutron stars or black holes while smaller stars, such as our Sun, shed their outer layers and become planetarium nebulae that complete their life cycle as white dwarfs. Our sun, for example, was once a red giant that shed its outer layers 5 billion years ago to shrink to a compact white dwarf.

The results come from the European Space Agency's Gaia space telescope which examined the colors and brightness of 15,000 stars, the remnants of so-called white dwarfs around 300 light years from Earth.

In a billion years, our dead sun could turn into a giant cosmic jewel, according to a new study. At the moment, our own sun is a middle-aged star, but most of the stars around it become white dwarfs. Exploring how stars become white dwarfs helped Denis learn about the history and future of the sun.

As soon as a star begins to collapse, it heats up and begins to merge its last remaining hydrogen nucleus into a burning shell, expanding into a red giant. In its main sequence, the hydrogen-coating phase, our Sun still has about 4.5 billion years to go before entering the next phase of its life and inflating to become a red giant. During this volatile and turbulent phase, massive amounts of stellar material race through space, and the suns "bodies grow to about 100 times their current size before they become a red giant.

For a star with the mass of the Sun, increasing the core temperature is a greater burden because its helium is too hot to merge with carbon. Carbon burned in a red giant star releases about ten times as much energy as in a dwarf star. After about two billion years of its giant red phase, the hot core of stars will be enveloped by the ash from the helium layer that burned it.

A few hundred million years after a carbon-burning red giant star burns its helium, everything collapses. Red giants have only been around for a very short time - about a billion years, compared to the tens of billions that the same star burns up in our own sun.

Red giants are hot enough to transform helium into their nuclei, which is produced by fusing hydrogen with heavier elements such as carbon. Such stars burn hydrogen when they use fuel from nuclear fusion. But most stars are not massive enough to generate the pressure and heat needed to burn heavy elements by fusion, so heat production stops.

Knowing how stars become crystal balls is interesting, but it also has practical implications for astronomers. Professor Denis Sullivan is studying white dwarfs, small, dense stars that are cooler than red giants. His White Dwarf Laboratory studies the evolution of stars and can tell us what will happen to our sun in the future.

In main sequence stars such as our Sun, nuclear fusion converts hydrogen into helium. Most stars run out of hydrogen, so they expand into red giants or shrink into cool white dwarfs. The helium composition is the fate of the red dwarf stars of the M-class, which make up about 40% of the solar mass.

If your star has more than eight times the mass of the Sun, it will not merge hydrogen into helium but helium into helium and carbon, triggering a carbon fusion that leads to oxygen fusion, silicon fusion and the spectacular death of a supernova. When your star is eventually made up of carbon, oxygen and light, the outer layers of hydrogen and helium are blown away. When the star is like the sun by contracting at high temperatures, the nucleus runs out of hydrogen and it begins helium fusion to carbon, and it swells to a red giant.