Production rates of comet C2020/F3 (NEOWISE) from high resolution spectroscopy
- 1INAF-Osservatorio Astronomico di Padova, Padova, Italy (giovanni.munaretto@inaf.it)
- 2INAF Astronomical Observatory of Trieste, Via Tiepolo 11, 38121 Trieste, Italy
- 3Fundación Galileo Galilei-INAF, Rambla José Ana Fernandez Pérez 7, 38712 Breña Baja, TF, Spain
- 4Instituto de Astrofisica de Canarias, C/Via Lactea s/n, 38205 La Laguna, Tenerife, Spain
- 5Departamento de Astrofisica, Univ. de La Laguna, Av. del Astrofisico Francisco Sánchez s/n, 38205 La Laguna, Tenerife, Spain
- 6INAF Astronomical Observatory of Arcetri, Largo Enrico Fermi 5, I-40125, Firenze, Italy
Introduction
Comets are the leftovers from the formation of the Solar System. Understanding their composition allow us to investigate the physical and chemical processes occurring at the early stages of its formation. In this contribution we analyze high resolution spectra of comet C/2020 F3 (NEOWISE) obtained with the High Accuracy Radial Velocity Planet Searcher (HARPS-N) echelle spectrograph at the 3.6 m Telescopio Nazionale Galileo (TNG). C/2020 F3 was discovered on 27 March 2020 as a long-period comet, the brightest one observed in the northern hemisphere since the Hale-Bopp in 1997. Its remarkable brightness offered a unique opportunity to investigate its composition through high-resolution spectroscopy, which is otherwise challenging on these targets due to their usual faintness. Our observations already allowed the identification of 4488 cometary emission lines belonging to C2, C3, CN, CH, NH2, Na I and [OI] [1]. We here follow up the molecular identifications by characterizing the gaseous environment of C2020/F3 through the analysis of the molecules’ production rates.
Dataset and Methods
We analyze one HARPS-N spectra of C/2020 F3 obtained on 26 July, at a heliocentric distance of 0.72 AU, covering the wavelengths between 383-693 nm at a spectral resolving power of 115000. We reduced the spectrum by performing absolute calibration, sky subtraction and dust-continuum normalization using IRAF routines and observations of the spectrophotometric standard HR5501 and the solar analog Land 107-684. The calibrated spectra were used in combination with the identified line identification [1] to measure the fluxes of given bands of molecules CN (388.3 nm band), C2 (516.5 nm band), C3 (405.0 nm band), NH2 (577.4 nm band) and OI (630.0 nm line). For each emission line or band, the flux was measured in IRAF through a fit of multiple gaussian profiles, centered at the catalog wavelengths. Cometary production rates are then estimated using a Haser model [2] which parameters were derived from literature studies (e.g., [3])
Results
We estimate production rates of Q[CN]=2.2*1026 , Q[C2]=2.28*1026 , Q[C3]=2.15*1027 and finally Q[NH2]=1.08*1027 . We estimate a H2O production rate of Q[H2O]=2.89*1029 , using the OI emission line at 630 nm, therefore assuming that all the flux of this line comes from dissociation of water. Our estimate is in agreement with independent estimates from the SOHO/SWAN instrument[4]. A detailed analysis of the production rate and their comparison with other comets will be presented at the conference.
References
[1] P.Cambianica, et al., 2021, A&A, 656, A160.
[2] Haser, L. 1957Bull. Soc. R. Sci. Liege, 43 (1957), pp. 740-750
[3] Langland-Shula, L., Smith, G. H.,2011, Icarus, Volume 213, Issue 1, 2011, 280-322, 0019-1035
[4] M. R. Combi et al 2021 ApJL 907 L38
How to cite: Munaretto, G., Cambianica, P., Cremonese, G., Fulle, M., Boschin, W., Di Fabrizio, L., Harutyunyan, A., Podio, L., and Codella, C.: Production rates of comet C2020/F3 (NEOWISE) from high resolution spectroscopy , Europlanet Science Congress 2022, Granada, Spain, 18–23 Sep 2022, EPSC2022-360, https://doi.org/10.5194/epsc2022-360, 2022.
