Name: Megha Anand
Affiliation: Inter-University Centre for Astronomy and Astrophysics
Conference ID : ASI2022_325
Title : Mg II core-to-wing ratio and its center to limb variation in sunspots from IRIS
Authors : Authors: Megha Anand (1), Durgesh Tripathi (1), and Pradeep Kayshap (2) Affiliations: (1) Inter-University Centre for Astronomy & Astrophysics, Post Bag - 4, Ganeshkhind, Pune 411007, India (2) Vellore Institute of Technology (VIT) Bhopal, VIT Bhopal University, Kothri Kalan, Sehore-466114, M.P., India
Abstract Type: Oral
Abstract Category : Sun and the Solar System
Abstract : The Mg II core-to-wing ratio, also known as the Mg II index, is an important tracer for solar irradiance studies due to its strong correlation with the temporal variation of solar UV flux. It is widely used for Sun climate studies because of its long-term precision and insensitivity to instrumental artifacts. Earlier results have shown that the Mg II index's sensitivity to both rotational modulation and long-term solar cycle variation can be increased with a higher spectral resolution. To date, the Mg II index has been studied, assuming Sun as a star using low (11 Å) and medium spectral resolution (1Å) data. Our aim is to study the Mg II index for different solar features using high spectral and spatial resolution data provided by the Interface Region Imaging Spectrometer (IRIS). Using the spatially resolved data, we present the preliminary results on the center to limb variation of the Mg II index in the case of both sunspot umbra and penumbra. This would provide us an opportunity to understand the importance of spatially resolved Mg-II index on total solar irradiance (TSI) and solar spectral irradiance (SSI), which can be a foundation stone for understanding the Sun-climate relationship using the Solar Ultraviolet Imaging Telescope (SUIT) onboard the Aditya-L1 mission.