Astronomers have captured an image of what our sun will look like at the ‘very end’.
Using the European Southern Observatory’s (ESO) Very Large Telescope, astronomers caught a glimpse of what the future holds for our very own solar system.
Looking more than 500 light years into deep space they’ve looked in great detail at the end of a star – and it’s one just like our own Sun.
The image is of the ageing red giant π1 Gruis and is known to be similar to the Earth’s Sun.
The ESO website says:
This remarkable new image from the PIONIER [Precision Integrated-Optics Near-infrared Imaging ExpeRiment] instrument reveals the convective cells that make up the surface of this huge star, which has 350 times the diameter of the Sun.
Each cell covers more than a quarter of the star’s diameter and measures about 120 million kilometres across. These new results are being published this week in the journal Nature.
Located 530 light-years from Earth in the constellation of Grus (The Crane), π1 Gruis is a cool red giant. It has about the same mass as our Sun, but is 350 times larger and several thousand times as bright. Our Sun will swell to become a similar red giant star in about five billion years.
ESO says the international team of astronomers were able to view Gruis in greater detail than ‘ever before’.
They found the surface of the red giant had just a ‘few convective cells’, which were each about 120 million kilometres across — about a quarter of the star’s diameter.
Just one of these granules would extend from the Sun to beyond Venus. What?
The surfaces, known as photospheres, of many giant stars are ‘obscured by dust’ and these can mean observations are often difficult.
π1 Gruis has dust ‘far from the star’ but according to ESO, it does ‘not have a significant effect on the new infrared observations’.
The ESO website adds:
When π1 Gruis ran out of hydrogen to burn long ago, this ancient star ceased the first stage of its nuclear fusion programme.
It shrank as it ran out of energy, causing it to heat up to over 100 million degrees. These extreme temperatures fueled the star’s next phase as it began to fuse helium into heavier atoms such as carbon and oxygen.
This intensely hot core then expelled the star’s outer layers, causing it to balloon to hundreds of times larger than its original size. The star we see today is a variable red giant. Until now, the surface of one of these stars has never before been imaged in detail.
In comparison, the Sun’s photosphere contains ‘about two million convective cells’, with diameters of around 1,500 kilometres, typically.
The vast size differences in the cells of the two stars can be explained in part by their ‘varying surface gravities’.
π1 Gruis is only 1.5 times the mass of the Sun but it is ‘much larger’. This results in a ‘much lower’ surface gravity and just a few extremely large granules.
Previous studies of π1 Gruis found a ‘shell of material 0.9 light-years away’ thought to have been ejected around 20,000 years ago.
This period in a star’s life lasts ‘just a few tens of thousands of years’, in comparison to the overall lifetime of several billion.
Isn’t space fascinating?