Astronomers have compared the sun to hundreds of similar stars to understand how “normal” the sun really is,media reported. It turns out that it is actually far less active than its companions. In many ways, the sun is completely ordinary. This is a G-shaped star in the middle of life. Its energy output and brightness can reliably track an 11-year sunspot cycle.
But because this is a sample size this doesn’t tell people if this is a normal star. So astronomers from Max Planck, the University of New South Wales and the Korea Institute of Space Research compared the sun to other similar stars.
Using data from the Kepler and Gaia space telescopes, the team screened the sun-like stars from 150,000 primary stars. Since the rotation cycle is the main criterion — the sun rotates every 24.5 days — the researchers are looking at stars with a rotation period of 20 to 30 days. They then further narrowed the list by looking for the stars closest to the sun’s surface temperature, age and element almost ratio. Finally, they identified 369 solar-like stars.
To the team’s surprise, the sun seems to be much quieter than most other stars. Solar radiation fluctuates only 0.07 percent between active and inactive periods, while other stars typically fluctuate five times more.
And it’s not short-term. Thanks to early and enthusiastic astronomers, reliable sunspot records date back to around 1610, when solar activity could be estimated by isotopes in tree wheels and ice cores, dating back 9,000 years. During this time, the researchers found that the changes in the sun were in a fairly stable range. So does this mean that the sun is a naturally quiet star or is it just going through a phase?
“9,000 years is like a blink of an eye compared to the sun’s entire lifespan,” said Timo Reinhold, lead author of the study. It is conceivable that the sun has been going through a period of calm for thousands of years, so we have a distorted image of our stars. “
The team says the data suggest that the sun may be much more active than people think.