Nothing in the world lasts forever and neither will our life and light-giving star Sun. Currently going through its middle age, the Sun is estimated to be 4.57 billion years, according to data from the European Space Agency’s Gaia spacecraft. The star mapping mission from the space agency has revealed further information about the fate of the Sun and how it will evolve. However, there is no need to worry since we will not be around by that time.
The study tries to predict the future of the Sun by identifying how will the stars of similar mass and composition will evolve. According to the data released, the Sun is currently fusing its hydrogen core to helium, a process known as nuclear fusion, and is generally rather stable.
But the giant star will eventually die. This will happen as it will continue to grow hotter and hotter and then gradually run out of hydrogen. In order to bring in hydrogen, the core will contract and form a hydrogen shell. While the core contracts, the outer atmosphere of the Sun will expand, eating the Earth and even engulfing Mars. This will turn the Sun into a red giant, lowering its surface temperature in the process.
When the core of the Sun will eventually run out of both the gases (hydrogen and helium), it will pour out all of its outer material forming a planetary nebula. The core will meanwhile continue to cool down and collapse into a dim white dwarf.
The star of our solar system is expected to reach its maximum temperature at approximately 8 billion years of age. It will then cool down and continue to increase in size becoming a giant red star. It will reach the end of its life at the age of 10-11 billion years.
Orlagh Creevey from Observatoire de la Côte d’Azur, France, and collaborators from Gaia’s Coordination Unit 8 combed the data looking for the most accurate stellar observations which the spacecraft could offer. They focused on stars that have surface temperatures between 3000K and 10000K since such stars are broadly similar to the Sun which has a surface temperature of 6000K. These are also the longest-lived stars in the galaxy.
“If we don’t understand our own Sun and there are many things we don’t know about it how can we expect to understand all of the other stars that make up our wonderful galaxy,” Orlagh was quoted as saying in a statement.
Gaia is a space observatory of the ESA, designed for astrometry (measuring the positions, distances and motions of stars with unprecedented precision). It was launched in 2013 and is expected to be operational until 2025.