Notice: A session had already been started - ignoring session_start() in /var/www/html/events/TVS/config.php on line 26
TVS 2025
The Variable Sun
Past, Present, and Future Perspectives
13th - 17th October, 2025
Organizers: IIST, ANRF, IIA, ARIES, IISER Kolkata & University College, Thiruvananthapuram, India
Registration
Poster
Scientific Program
Image Credit: NASA/ESA/SOHO
Abstract Details
Name:
Dr. Prithvi Raj Singh
Affiliation:
Department of Physics, University of Allahabad, Prayagraj
Conference ID:
TVS202510116
Title:
Solar Rotational Variation of Solar Activity Parameters during the Period (2009 to 2012 and 2020 to 2023)
Authors and Co-Authors:
C. M. Tiwari
Abstract Type:
Contributory Presentation
Abstract:
We study the chromospheric activity proxies of Lyman alpha, Mg II, and Ca II (H & K) lines of intensity profiles during solar cycle 24 (January 2009 to December 2012) and for solar cycle 25 (January 2020 to December 2023). The Ca II (H & K) lines, with their wavelength representing the visible solar spectrum, the H line at 3968.469 Å, and the K line at 3933.663 Å. The composite solar Lyman alpha includes the wavelength of 121.56 nm, and Mg II index with wavelength 280 nm. We observed a solar rotational period of ~25 days of SSN, Lyman alpha, Mg II, and Ca II (H & K) lines, and their distinct spectrum profiles were produced by wavelet methods. We found that the above chromospheric proxies are a good indicator of solar activity, and it is strongly correlated with the photosphere (sunspot number). Keywords: Composite Solar Lyman alpha index and Mg II index, Mg II and Ca II (H & K) lines, Sunspot Number