The sun won’t stay up forever. The star that powers our solar system can be predicted by scientists. We won’t be around to see it, though.

By finding stars with similar mass and composition and predicting how our Sun will change in the future, the ESA’s Star Mapping GAIA project now offers a view into the Sun’s future. Let’s look at what will occur in the future even if the Earth has less time than the Sun.

We already know that “nuclear fusion” powers the Sun. The Sun will continue to heat up over the next few billion years, eventually exhausting its hydrogen supply. The hydrogen would then come together to form the nucleus as the core would then begin to contract.

The Sun’s outer atmosphere starts to rapidly expand as its core contracts, enveloping Mars and Earth and turning the Sun into a red giant.

The Sun’s core will expel all of its outer material and transform into a planetary nebula when it runs out of hydrogen and helium, while the core will collapse into a white dwarf.

While this is based on how other stars have grown over time, it is crucial for Earth dwellers to have an idea about our planet’s and the Sun’s destiny.

Figure 1 is a sky map of stellar age from Gaia Data Release 3 that displays the average age of the stars in our galaxy, with blue stars being younger and red stars being older. Outside of the galactic disk, most of the oldest stars are to be found. Using the Final Luminosity Age Mass Estimator, the age was calculated (FLAME). An arbitrary sample of 10 million stars from Gaia DR3 are displayed in this map. ESA/Gaia/DPAC – CC BY-SA 3.0 IGO are the sources. acknowledgements: produced by the Gaia team at MPIA, M. Fouesneau, and O. Creevey

The third and most recent data release (DR3) from ESA’s GAIA mission sheds light on the Sun’s life cycle. “One of the key results of this release was a database of millions of stars’ intrinsic attributes. These factors include their temperature, mass, and the amount of mass they contain.”

Figure 2 shows a Hertzsprung-Russell diagram with samples of young, massive stars (OBA), intermediate-mass stars (FGKM), ultra-cool, low-mass dwarf stars (UCD), and solar analogs. Credits: ESA/Gaia/DPAC – CC BY-SA 3.0 IGO based on Creevey et al. 2022 and the Gaia Collaboration.

The Hertzsprung-Russell (H-R) diagram is used by the GAIA mission to plot precise readings of the star’s apparent brightness and color taken from Earth.

The effective surface temperature of a star is shown versus its intrinsic brightness on an HR diagram. It demonstrates how stars transform throughout the course of their extensive lives.

While a star’s mass doesn’t change much over its lifetime, as it ages, different nuclear fusion events cause the star’s temperature and size to change in the core.

Our Sun is at its middle age and stationary condition at 4.57 billion years old. However, as the Sun ages, this stability will change. That’s where the most recent GAIA mission data (DR3) comes in.

Orlagh Creevey of the Observatoire de la Côte d’Azur in France and colleagues from Gaia’s Coordination Unit 8 analysed the data for the most precise stellar observations that the satellite could provide.

Figure 3: The Gaia DR3 RVS spectra of 1046 solar analogues. Outer grey contour includes 90% of the sample. Inner grey contour contains 68% of the sample. The most prominent absorption lines are marked with vertical dashed lines. Credits: ESA/Gaia/DPAC – CC BY-SA 3.0 IGO. The image is adapted from the one presented in Gaia Collaboration, Creevey et al. 2022. Acknowledgements: Rene Andrae, Andreas Korn, Orlagh Creevey, Georges Kordopatis, Rosanna Sordo.

They concentrated their attention on stars with surface temperatures ranging from 3000K to 10000K since they are similar to the Sun, which has a surface temperature of 6000K.

Furthermore, because these are the longest-living stars in the Milky Way, they can tell the Milky Way’s history. They are also promising candidates for the discovery of exoplanets.

Once the findings were filtered, only stars with masses and chemical compositions comparable to the Sun were shown. Because they let ages to fluctuate, the stars they selected traced a line in the H-R diagram that depicts our Sun’s history from its past to its future. This suggests that as humans become older, the Sun’s brightness and temperature vary.

The research shows that our Sun will reach its peak warmth at around 8 billion years old, then cool and grow larger until it reaches its red giant stage at around 10–11 billion years old.

Following this phase, the Sun will near the end of its life and change into a weak white dwarf.

How long will Earth stay in our proximity?

Although Earth is 8 billion years ahead of the Sun, it has a far shorter time scale of 1 billion years. This is because the Sun’s brightness and temperature are increasing by 10% per billion years. While this increase in brightness and temperature may seem small, it would sufficiently warm Earth to support all life.

Orlag and his colleagues looked for stars that were similar to the Sun in terms of temperature, surface gravity, composition, mass, and radius. He was awarded 5863 stars that met his requirements.

It also brings a glimmer of hope to our way of life because there is always a chance that we will find Earth-like planets among the 5863 stars like our Sun.

Right now, we are unsure whether there is a planet that could host life right now, but we’re looking.

Soucre: news.sci-nature.com