Follow-up spectroscopy of comet C/2020 F3 (NEOWISE)

Abstract

We present spectroscopy of the coma center of comet C/2020 F3 (NEOWISE), carried out at the end of July 2020 with the \'Echelle spectrograph FLECHAS at the University Observatory Jena. The comet was observed in 5 nights and many prominent emission features were detected between 4685\r{A} and 7376\r{A}. Beside the C$_2$ Swan emission bands also several emission features of the amidogen radical, as well as two forbidden lines of oxygen were identified in the FLECHAS spectra of the comet in all observing epochs. In contrast, strong sodium emission was detected only in the spectra of the comet, taken on 21 and 23 July 2020, which significantly faded between these two nights, and was no longer present in the spectra as of 29 July 2020. In this paper we present and characterize the most prominent emission features, detected in the FLECHAS spectra of the comet, discuss their variability throughout our spectroscopic monitoring campaign, and use them to derive the radial velocity of the comet in all observing nights.