High-resolution TNG/HARPS-N spectroscopy of comet C/2022 E3 (ZTF)

Comet C/2022 E3 (ZTF) is a long-period, hyperbolic comet that became bright around its 2023 perihelion passage. We present a high-resolution spectroscopic analysis aimed at identifying the main molecular emissions in the coma and deriving the production rates of the detected species. We obtained a high-resolution spectrum of C/2022 E3 on 2 February 2023 with the HARPS-N échelle spectrograph at the 3.6-m Telescopio Nazionale Galileo, covering the 3830–6930 Å wavelength range at R ≈ 115 000. We identify emission lines of C 2 , C 3 , CH, CN, NH 2 , and [OI] in the coma of C/2022 E3. The ratio between the oxygen green and red lines yields G/R = 0.15 ± 0.02, indicating H 2 O as the dominant parent molecule producing atomic oxygen. Production rates were derived for the detected species, and the resulting C 2 /CN ratio places C/2022 E3 among typical carbon-chain composition comets. Comparison with literature surveys further confirms that its abundance ratios relative to H 2 O are consistent with the bulk of long-period comets.