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Published online by Cambridge University Press: 06 October 2025
We present new high-spectral resolution échelle spectra of IC 4997 obtained in 2023 June to study the evolution of its recently reported variable Hα emission line profile. Compared with similar spectra from 2020 September, the new ones also show a single-peaked profile but the full velocity width of the Hα wings has increased by a factor of; 1.2. Besides, we use our high-resolution échelle spectra to investigate the internal kinematics of the nebula. Preliminary analysis suggests that the two shells of IC 4997 are kinematically resolved: the outer shell expands at; 10–14 km s-1 and the inner shell at; 25 km s-1.