Kodaikanal: To understand the future of the Sun is crucial for our existence in the times that lie ahead. The Sun is the driver for space weather conditions hence understanding the fate of the Sun will also shape plans for space exploration.
In this sense, observations of the Sun corresponding to the last century allow scientists to peek into the past. The digitised record of solar observations over more than 100 years taken on photographic plates/films can help scientists around the world strengthen their studies of solar variability and its impact on climate, spanning it over a longer time scale.
In this context, the longest continuous observations of the Sun taken from Kodaikanal Solar Observatory (KoSO)–one of the oldest astronomical observatories have been digitised and made available for community use. These historical observations can enable scientists to understand the behaviour of Earth’s nearest star in its earlier phase, and based on that, they can predict its future.
Crucial sunspot data from KoSO, a field station of the Indian Institute of Astrophysics (IIA), Bengaluru, was usable for scientific analysis for the period of 1921-2011 due to some significant issues in the data. Researchers from two autonomous institutes under the Department of Science and Technology, Ministry of Science and Technology (DST), Government of India, namely Aryabhatta Research Institute of Observational Sciences, Nainital, and Indian Institute of Astrophysics, Bangalore, led by Bibhuti Kumar Jha, have solved these issues in the data and made one of the most homogeneous and extended sunspot data series for around 115 years (1904-2017). The new results have been published in a recent article in the journal Frontiers in Astronomy and Space Sciences.
The data is available as open data that can benefit students and scientists across the world. This data will be a vital asset for the solar community for understanding the behaviour of the Sun in the past, over more than a century, and predicting the future of our life-giving star.
“Apart from pictures of the Sun taken in white light from the same telescope and also those of Ca-K spectra from the chromosphere plasma, we are also digitising daily hand-drawn pictures of sunspots over a period of 100 years which have been preserved at the KoSO. Artificial Intelligence will be used to extract data from hand-drawn pictures and photographs. This will form a set of one of the oldest, rare, continuous solar data that will be useful to researchers from different corners of the world,” said Dr Dipankar Banerjee, Director of Aries and one of the authors of the paper.
