High-resolution optical spectroscopic observations of comet 21P/Giacobini-Zinner in Its 2018 apparition

Abstract

Comet 21P/Giacobini-Zinner is a peculiar comet from the viewpoints of the chemical and physical properties of its dust grains. We conduct optical high-resolution spectroscopic observations of the comet. The intensity ratios of forbidden oxygen lines (at 557.7, 630.0, and 636.4 nm) and ortho-to-para abundance ratios (OPRs) of water cations (H${}_2$O${}^{+}$) and amidogen radicals (NH${}_2$) are obtained while only the upper limit for ${}^{14}$N/${}^{15}$N in the amidogen radical is restricted. The OPRs of H${}_2$O${}^{+}$ and NH${}_2$ are similar to those of other comets, although the real meaning of these OPRs is still debated. Based on the observation of the forbidden emission lines of oxygen atoms, it can be concluded that the comet is depleted in CO${}_2$. In consideration with the depletion in other highly volatile species found in the near-infrared region and the presence of complex organics in comet 21P/Giacobini-Zinner, this comet might form in a warmer region in the solar nebula compared with other comets.

12 pages, 6 figures, author final submission version, published to Astronomical Journal on April 13, 2020

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Cited by in corpus (4)

• The similarity of the interstellar comet 2I/Borisov to solar system comets from high resolution optical spectroscopy
• Photometry and high-resolution spectroscopy of comet 21P/Giacobini-Zinner during its 2018 apparition
• Comet 21P/Giacobini-Zinner: Water Production Activity over 20 Years with SOHO/SWAN
• Optical spectroscopy of comets using Hanle Echelle Spectrograph (HESP)