What type of study is this?

This is a Observational study (also classified as: In Vitro Study).

August 17, 2025

Ionic emission from and activity evolution in comet C/2020 F3 (NEOWISE): Insights from long-slit spectroscopy and photometry

Puntos clave

Ionic emission was detected at distances between 4x10^4 km and 1x10^5 km from the comet, revealing significant chemical activity.
Production rates of key molecules like OH and CN were measured during the observation period, indicating compositional evolution.
Analysis used low-resolution spectroscopy alongside narrow-band photometry to assess changes in emission and activity over weeks post-perihelion.
The comet's formation conditions are suggested by the derived gas ratios, indicating it likely originated in the cold mid-outer nebula.

Resumen

The long-period comet C/2020 F3 (NEOWISE) was the brightest comet in the northern hemisphere since C/1995 O1 (Hale-Bopp). These comets offer a unique opportunity to study their composition and the spatial variation in the different emission in detail. We conducted long-slit low-resolution spectroscopy and narrow-band photometry to track the evolution of its activity and composition during several weeks after perihelion. The images were used to compute the production rates of neutral molecular species and dust, and the spectrum was used to analyse the variation in the emission along the spatial axis in the sunward and anti-sunward directions to detect ionic emission. Narrow-band (OH 3090 Å NH 3362 Å CN 3870 Å C₂ 5140 Å C₃ 4062 Å BC 4450 Å GC 5260 Å and RC 7128 Å) and broad-band (Johnson-Cousins B, V, Rc, Ic) images of comet C/2020 F3 were taken with TRAPPIST-North from 22 July to 10 September 2022 to track the production rates, the evolution of the chemical mixing ratios with solar distance, and the proxy to the dust production (A (0) f̊ho). A long-slit low-resolution spectrum was obtained on 24 July 2020 using HFOSC on the 2 m HCT at IAO, Hanle. Spectra extracted along the spatial axis in the sunward and anti-sunward directions enabled a comparative analysis of the emission in both directions. We report production rates and mixing ratios of OH, NH, CN, C₂, C₃, and NH₂ and used the flux density of the forbidden oxygen line to derive the water-production rate. Ionic emission from N₂^+, CO^+, CO₂^+, and H₂O^+ was detected at 4times10⁴ km to 1times10⁵ km from the photocentre in the tail direction. The average N₂^+/CO^+ ratio for the CO^+ (3-0) and (2-0) bands measured from the spectrum was (3. 0±1. 0) which we further refined to (4. 8±2. 4) using fluorescence modelling techniques. We measured the CO₂^+/CO^+ ratio to be 1. 34±0. 21. Combining the N₂^+/CO^+ and CO₂^+/CO^+ ratios, we suggest the comet to have formed in the cold mid-outer nebula (∼50 K-70 K). Furthermore, the average rotation period of the comet was calculated to be 7. 28±0. 79 hours with a CN gas outflow velocity of 2. 40±0. 25 km/s.

Me gusta

Guardar

Cite This Study

Aravind et al. (Wed,) studied this question.

synapsesocial.com/papers/68a36a360a429f797332e34e https://doi.org/https://doi.org/10.1051/0004-6361/202554842

Also Consider

Synapse has enriched 3 closely related papers on similar clinical questions. Consider them for comparative context:

Me gusta

Guardar