Our Sun will not explode into a supernova when, eventually, it runs out of fuel, but this does not mean that there will be no fireworks.
When our Sun has exhausted hydrogen fuel in its core, the star will swell into a huge red giant and under the action of the most powerful stellar winds forms a planetary nebula with small, but dense white dwarfs in the center.
This transition from a dying star to a nebula is not considered slow, but is a rather “soft” process compared to a supernova explosion.
"After a few thousand million years, the Sun will exhaust nuclear fuel and become a red giant, dropping most of its mass," said lead researcher Jose Francisco Gomez from the Institute of Astrophysics of Andalusia (IAA-CSIC) in Granada, Spain. "The end result will be a white dwarf surrounded by a luminous planetary nebula. Despite the fact that every star with a mass below ten solar masses passes through this short but important process, many details of this process are still not clear."
The research team Gomez focused on IRAS 15103-5754 - an object that is currently moving from a red giant to a planetary nebula. Objects such as IRAS 15103-5754 generate powerful emissions that form water vapor molecules. That is why such a jet of discarded material can be detected by scientists. As part of a wider study of 16 dying stars, IRAS 15103-5754 was distinguished by the fact that the speed of its jets increased with distance. This may be the key to understanding the dynamics of planetary nebulae and dying stars like our Sun.
"Water molecules are usually destroyed shortly after a planetary nebula is formed. In these cases, the speed of the jets is always very low," said employee Louis F. Miranda of the University of Vigo, Spain. "In IRAS 15103-5754, we see that the emission rate reaches hundreds of kilometers (miles) per second. We are witnessing the transition of a star into a planetary nebula in real time."
“High speed can only be explained by an explosion,” said Gomez.
When we look deep into our galaxy, we see a huge variety of planetary nebulae, a fact that is not so easily explained by modern theories. Now that astronomers have determined that the formation of this type of nebulae is accompanied by an explosion, we will have a better idea of what happens soon after the death of a star like our Sun.