Studying a nearby star has given scientists a fascinating insight into how the Sun may have behaved billions of years ago.
A team of international astronomers, including professor Stefan Kraus of the University of Exeter in Britain, used cutting-edge techniques to create the first direct image of surface structures on the star Zeta Andromedae – found 181 light years from Earth.
In order to image the star’s surface during one of its 18-day rotations, the researchers used a method called interferometry where the light of physically separate telescopes is combined in order to create the resolving power of a 330m telescope.
Found in the northern constellation of Andromeda, the star showed signs of “starspots” – the equivalent of sunspots found within our own solar system. The pattern of these spots differs significantly from those found on the Sun.
The researchers suggest these results challenge current understandings of how magnetic fields of stars influence their evolution.
Furthermore, they believe that the findings offer a rare glimpse of how the Sun behaved in its infancy, while the solar system was first forming.
“Most stars behave like giant rotating magnets and ‘starspots’ are the visible manifestation of this magnetic activity. Imaging these structures can help us to decipher the workings that take place deep below the stellar surface,” said Kraus.
“While imaging sunspots was one of the first things that astronomer Galileo Galilei did when he started using the newly-invented telescope, it has taken more than 400 years for us to make a powerful enough telescope that can image spots on stars beyond the Sun,” added John Monnier, professor of astronomy in University of Michigan.
It’s important to understand the Sun’s history because that dictates the Earth’s history — its formation and the development of life.
“The better we can constrain the conditions of the solar environment when life formed, the better we can understand the requirements necessary for the formation of life,” said Rachael Roettenbacher, who conducted this research as part of her doctoral thesis at University of Michigan.
The findings were published in the scientific journal Nature.