Near-sun characteristics of a CME inferred from observations in the 5303 Å coronal emission line

Abstract

Using observations of the solar corona in the 5303 Å (Fe XIV) emission line with the Visible Emission Line Coronagraph (VELC) on board Aditya-L1, we estimated the electron density (Ne), thermal energy (ECME), and mass (MCME) of a coronal mass ejection (CME) very close to the Sun at heliocentric distance r ≈ 1.06R⊙. The corresponding values are Ne ≈ 3.7 × 108 cm−3, ECME ≈ 9.4 × 1028 erg, and MCME ≈ 2.7 × 1014 g, respectively. The procedure adopted suggests a possibility to understand the properties of the CMEs in the visible wavelength range, particularly during the temporal phase close to their onset. The widths and Doppler velocities of the line are nearly constant in the VELC field of view (FoV ≈ 1.06–1.50R⊙). The values are ≈0.85 Å and ≈+2 km s−1, respectively.