Abstract Details
| Name: Subhamoy Chatterjee Affiliation: Indian Institute of Astrophysics Conference ID: ASI2017_757 Title : Extraction of Features and their Long-term Evolution from Century-long Ca II K data of Kodaikanal Observatory Authors and Co-Authors : Dipankar Banerjee Indian Institute of Astrophysics, Koramangala, Bangalore 560034, India; Center of Excellence in Space Sciences India, IISER Kolkata, Mohanpur 741246, West Bengal, India Abstract Type : Oral Abstract Category : Sun and the Solar System Abstract : Kodaikanal Solar Observatory (KSO) has archived Ca II K spectroheliograms through photographic plates for about a century (1907 - 2007). Digitization and calibration of these plates have been carried out systematically. We have used those calibrated Ca II K images to extract features of different spatial scales. Plages, the bright on-disc features with projected area ≥ 1 arcmin^2, have been segregated in an automated way and parameters like, area and centroid locations have been recorded. Using those extracted parameters, century-long evolution of plages has been studied. To confirm plages as magnetic proxy we correlated their locations with magnetic patches through construction of Carrington maps from both MDI/SoHO line-of-sight magnetograms and Ca II K spectroheliograms from KSO for overlapping rotations. Exploiting the Ca II K data we also tried to estimate the scales and other geometrical parameters of supergranules without manual intervention. We could study the correlation of solar cycle and temporal evolution of supergranule parameters for many cycles because of availability of 100 years’ data at KSO. Moreover, using plage detection we divided full solar disc into active and quite regions. For each of those regions we again recorded the temporal evolution of supergranule parameters as mentioned before. We found in phase and out of phase correspondences between sunspot number cycle and supergranule parameter cycle for aggregate and segregated regions. This study gave a hint about complex solar dynamo operating inside the sun at different spatial scales with influence of magnetic fields. |