Kodaikanal Solar Observatory AI Study

Researchers used artificial intelligence to analyse more than a century of hand-drawn solar observations from the Kodaikanal Solar Observatory in Tamil Nadu. The study used digitised solar charts from 1904 to 2022 and created a long continuous record of solar magnetic activity.

Kodaikanal Solar Observatory

The Kodaikanal Solar Observatory, also called KoSO, is a solar observatory in Tamil Nadu and is known for its long-running solar records. Its hand-drawn “suncharts” document daily solar observations and form a historical archive used in solar physics.

AI Method and Solar Data

The study applied a U-Net-based supervised machine learning model to digitised suncharts. The model detected and mapped plages, which are bright and magnetically active regions on the Sun, across observations from 1916 to 2007. The extracted data covered nine full solar cycles. Scientists used the data to generate a time-latitude butterfly diagram, a standard solar-physics chart that plots the migration of magnetic activity across latitudes during successive solar cycles.

Institutions and Publication

The research was led by Dibya Kirti Mishra of the Aryabhatta Research Institute of Observational Sciences, an autonomous institute under the Department of Science and Technology. The study involved the Indian Institute of Space Science and Technology, the Southwest Research Institute in the United States, and the Indian Institute of Astrophysics. The findings were published in The Astrophysical Journal, a peer-reviewed journal in astronomy and astrophysics.

Important Facts for Exams

• Plages are bright regions in the Sun’s chromosphere and are associated with strong magnetic fields.
• A butterfly diagram is used in solar physics to track the latitude-wise movement of solar activity over time.
• U-Net is a convolutional neural network architecture widely used for image segmentation tasks.
• The Department of Science and Technology is a ministry-level department of the Government of India.

Solar Cycle Context

The solar cycle is an approximately 11-year cycle of changing solar magnetic activity. Solar observations from long archives such as KoSO are used to study solar cycle evolution and space weather.