A team of international solar researchers, led by Bibhuti Kumar Jha, a PhD scholar from the Aryabhatta Research Institute of Visual Sciences (ARIES) in Nainital, has designed a rotating image of the Sun after studying the various behaviors of solar spots observed over 100 years.
Sunspots are small and dark but there are colder places on the surface of the sun with strong magnetic forces.
The image of the sun’s orbit is based on the fact that the largest solar spots orbit at a slower rate compared to the smallest ones.
“The presence of strong magnetic fields around larger sunspots prevents them from gaining faster circulation speeds. This is in contrast to smaller sunspots which have a less intense magnetic field allowing it to orbit faster, ”said Jha.
Researchers at ARIES, in collaboration with their peers at the Max Planck Institute for Solar System Research, Germany and the Southwestern Research Institute, USA, studied several thousand digital images of recovered sunspot images from photographs and old films. The images were created by the Kodaikanal Solar Observatory (KoSO) between 1923 and 2011.
Run by the Indian Institute of Astrophysics, Bengaluru, KoSO has a repository of about 4 lakh images of the Sun recorded since 1904. They have all been digitized in recent years.
Unlike Earth – a solid body mass with uniform orbit, the Sun has varying degrees of rotation. This means, the solar equator rotates faster than its poles. The scientists have tried to find solar spots at different latitudes of the Sun to understand the rotational behaviors at different latitudes.
In addition, sunspots and solar eclipses have helped scientists understand the behavior of the sun from the past. These will still be visible characters to predict the future of the sun.
However, what makes challenging sunspots challenging is the timing and position of the sun’s surface. In general, they begin to appear at higher latitudes and move further toward the equator as the solar cycle (lasting 11 years) progresses.
“We don’t always see sunspots across all latitudes. As sunspots do not appear beyond 45 degrees latitude, sunspots are not formed around the poles, ”said Dipankar Banerjee, director, ARIES, and colleague of the study An Indian Express.
Due to limited camera resolution at the time of capturing images during telescope observation, results from several previous studies were based solely on larger solar spots. But in the KoSO image data set solar spot images were captured of all sizes. “Even using the dynamo models, the degree of variability is still unpredictable,” Banerjee said.
Contrary to popular belief, no change in circulation rates was observed between solar activity levels, i.e., between solar supply and minima, the researchers confirmed.
If he can understand solar dinamo, he can get a better view of the solar cycle and that will help predict how the sun will behave in the future, Jha said.