When the core of the former red giant has exhausted all of its fuel and shed all the gas it can, the remaining dense stellar cinder is called a white dwarf. The white dwarf is considered “dead” because atoms inside of it no longer fuse to give the star energy.
Their cores get hot enough to burn carbon, which our sun never will, and they eventually die in powerful supernova explosions. When it's all said and done, these massive stars leave behind either a neutron star or a black hole.
After a low- or medium-mass star has become a red giant, the outer parts grow bigger and drift into space, forming a cloud of gas called a planetary nebula. The core of the star that is left behind cools and becomes a white dwarf. The white dwarf eventually runs out of fuel and dies as a black dwarf.
All red supergiants will exhaust the helium in their cores within one or two million years and then start to burn carbon. This continues with fusion of heavier elements until an iron core builds up, which then inevitably collapses to produce a supernova.
Earth may just outrun the swelling red giant but its proximity, and the resulting rise in temperature, will probably destroy all life on Earth, and possibly the planet itself.
In a few billion years, the sun will become a red giant so large that it will engulf our planet. But the Earth will become uninhabitable much sooner than that. After about a billion years the sun will become hot enough to boil our oceans. The sun is currently classified as a “main sequence” star.
After a massive red giant star ejects its outer layers, its hot inner core is exposed, and it becomes a blue giant star. An object with a mass less than about 8% of the mass of the Sun, but about 10 times greater than that of Jupiter.
"Given that this system is an analog to our own solar system, it suggests that Jupiter and Saturn might survive the sun's red giant phase, when it runs out of nuclear fuel and self-destructs." Our sun is expected to move through a few phases when it dies.
“Given that this system is an analog to our own solar system, it suggests that Jupiter and Saturn might survive the Sun's red giant phase, when it runs out of nuclear fuel and self-destructs.”
Red Giant with LARGE MASS (>8ms) produces Type II Supernova, leaving behind: Neutron star, or Black Hole.
White dwarf
These faint stars are what remain after a red giant star loses its outer layers. They are about the size of the Earth and will eventually lose their heat to become a cold, dark black dwarf. The sun will eventually turn into a white dwarf and then a black dwarf.
It has entered its second red giant phase. What happens next depends on the mass of the star. Low-mass, Sun-like stars enter the planetary nebula phase. Stars which contain more than 8 times the mass of the Sun are likely to explode as a supernova.