By using Sabaru Telescope, astronomers have detected an unidentified infrared emission band from comet 21P/G-Z.
21P/G-Z is s a periodic comet in the Solar System, called as 21P /Giacobini-Zinner, where thermal emissions from silicate and carbon grains.
In 1920, Michel Giacobin observed the comet in the constellation of Aquarius. It is 1.04 Au far from the Sun near its perihelion.
Along with, researcher publishes their results on November 18, 2019 in Icarus intitle “Unidentified Infrared Emission Features in Mid-infrared Spectrum of Comet 21P/Giacobini-Zinner“, Ootsubo et al.).
Due to Cooled Mid-Infrared Camera and Spectrometer (COMICS) in the Subaru Telescope, Researcher finds unidentified infrared emission band.
These unidentified infrared emissions are likely due to complex organic molecules, both aliphatic and aromatic hydrocarbons, contaminated by N- or O-atoms.
Considering the properties of the dust and organic molecules, comet 21P/G-Z might have originated from the circumplanetary disk of a giant planet like Jupiter or Saturn, where it was warmer than the typical comet-forming regions, Researcher Says.
In addition, Astronomers from the Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (ISAS/JAXA), Kyoto Sangyo University (KSU), National Astronomical Observatory of Japan (NAOJ), and Okayama University of Science (OUS) conducted mid-infrared spectroscopic and imaging observations of comet 21P/G-Z using COMICS since July 5, 2005.
The obtained spectrum of comet 21P/G-Z shows emission peaks of crystalline silicate grains, which are usually also seen in many other comets.
Comet 21P/G-Z is enriched in complex organic molecules. The enrichment of complex organic molecules requires a warm temperature or high energetic particle environment around the comet in the early solar nebula.
This study is financially supported by MEXT Supported Program for the Strategic Research Foundation at Private Universities and JSPS KAKENHI Grants-in-Aid for Scientific Research.
# 21P/G-Z #Comet
