What will our Sun look like after we die? Scientists have made predictions about what the end of our solar system will be like and when this will happen. And humans will not be there to see the final act.
Previously, astronomers thought it would become a planetary nebula (a luminous bubble of gas and dust) until tests suggested it should be a little more massive.
An international team of astronomers turned it around again in 2018 and found that a planetary nebula is, in fact, the most likely solar corpse.
The Sun is about 4.6 billion years old, measured by the age of other objects in the Solar System that formed at the same time. Based on observations from other stars, astronomers predict that it will reach the end of its life in about 10 billion more years.
There are other things that will happen along the way, of course. In about 5 billion years, the Sun will become a red giant. The core of the star will shrink, but its outer layers will expand into Mars orbit, engulfing our planet in the process. If it is still there.
One thing is for sure: right now, we’re sure we won’t be around. In fact, humanity has only a few billion years left until we find a way out of this rock. This is because the Sun increases its brightness by about 10 percent every billion years.
That doesn’t sound like much, but this increase in brightness will end life on Earth. Our oceans will evaporate and the surface will heat up too much for water to form. We will be as capable as possible.
It is what comes after the red giant that has proven to be difficult to identify. Several previous studies have found that in order for a bright planetary nebula to form, the initial star must have been up to twice as massive as the Sun.
However, the 2018 study used computer modeling to determine that, like 90 percent of other stars, our Sun is more likely to shrink from a red giant to become a dwarf. white and then end up like a planetary nebula.
“When a star dies, it expels into space a mass of gas and dust, known as its envelope. The envelope can reach half the mass of the star. This reveals the core of the star, which at this time in the star’s life it is running out of fuel, finally shutting down and before finally dying, “explained astrophysicist Albert Zijlstra of the University of Manchester in the United Kingdom, one of the authors of the paper.
“It is only then that the hot core makes the ejected envelope glow brightly for about 10,000 years, a brief period in astronomy. This is what makes the planetary nebula visible. Some are so bright that they can be seen from extremely great distances that they measure tens of millions of light-years, where the star itself would have been too faint to see. “
The data model the team created actually predicts the life cycle of different types of stars, to find out the brightness of the planetary nebula associated with different stellar masses.
Planetary nebulae are relatively common throughout the observable Universe, with celebrities such as the Helix Nebula, the Cat’s Eye Nebula, the Ring Nebula, and the Bubble Nebula.
Cat’s Eye Nebula (NASA / ESA)
They are called planetary nebulae not because they really have anything to do with the planets, but because, when William Herschel first discovered them in the late 18th century, they looked similar to the planets through the telescopes of the time.
Nearly 30 years ago, astronomers noticed something peculiar: the brightest planetary nebulae in other galaxies have about the same level of brightness. This means that, at least theoretically, by observing the planetary nebulae of other galaxies, astronomers can calculate how far apart they are.
The data showed that this was correct, but the models contradicted it, which has bothered scientists since the discovery was made.
“Old, low-mass stars should turn into much weaker planetary nebulae than young, more massive stars. This has become a source of conflict for the past 25 years,” Zijlstra said.
“The data said you could get bright planetary nebulae from low-mass stars like the sun, the models said it wasn’t possible, no less than about twice the mass of the sun would give a planetary nebula too faint to see -the”.
2018 models have solved this problem by showing that the Sun is approximately the lower limit of mass for a star that can produce a visible nebula.
Even a star with a mass less than 1.1 times that of the Sun will not produce visible nebulae. Stars larger up to 3 times more massive than the Sun, on the other hand, will produce the brightest nebulae.
For the other stars in between, the expected brightness is very close to that observed.
“That’s a good result,” Zijlstra said. “Now not only do we have a way to measure the presence of stars millions of years old in distant galaxies, which is a range that is remarkably difficult to measure, we’ve even figured out what the Sun will do when he will die! “
The research has been published in the journal Nature Astronomy.
An earlier version of this article was first published in May 2018.