Close-up of the Orion Nebula captured by the Webb Space Telescope First detection of ‘methyl cation’ | sorae space portal site

This is part of the Great Orion Nebula (M42), which is about 1,350 light-years away. It was created based on data obtained by “NIRCam” of the “James Webb Space Telescope” (using a total of 13 types of near-infrared filters). Since the Webb Space Telescope mainly observes wavelengths in the invisible infrared, To the human eye, the colors in the published images are color-coded according to the filters used during the acquisition.（※1）。

*1 … In this photo, 1.4 µm and 1.62 µm magenta, 1.64 µm and 1.82 µm blue, 1.87 µm and 2.1 µm cyan, 2.12 µm and 2.77 µm green, 3.0 µm yellow, 3.23 µm and 3.35 µm orange, 4.7 μm and 4.8 μm in red.

The ridge-like structure extending from top right to bottom left is called “Orion Bar”. Orion’s bar is thought to have been formed by ultraviolet light from the trapezoidal open cluster stars in the upper left of the image.

The intense ultraviolet light from massive stars erodes the nebula’s gas and dust, forming impressive filaments and cavities in a process called photoevaporation. In addition, atoms such as hydrogen, ionized by ultraviolet light, emit light, giving the nebula its faint, brilliant colour.

If you zoom in on the upper right of this image, you can see a small object buried in a vast nebula. According to the Space Telescope Science Institute (STScI), which operates the Webb Space Telescope, this is one of the protoplanetary objects (a proplyd, a photo-evaporated protoplanetary disk) called d203-506. At its center is a red dwarf star with a mass of about 10% that of the Sun, and the protoplanetary disk surrounding it is said to have been warped by exposure to ultraviolet radiation from massive stars.

[▲ جزء من سديم الجبار العظيم تم التقاطه بواسطة تلسكوب جيمس ويب الفضائي (يسار) ، صورة مكبرة (أعلى اليمين) ، وصورة مكبرة أخرى لجسم الكوكب الأولي d203-506 (أسفل اليمين). تم إنشاء الصورة على اليسار باستخدام كاميرا الأشعة تحت الحمراء القريبة (NIRCam) ، والصورة في أعلى اليمين بواسطة مرصد منتصف الأشعة تحت الحمراء (MIRI) ، والصورة في أسفل اليمين باستخدام بيانات المراقبة من NIRCam و MIRI (Credit: ESA / Webb و NASA و CSA) و M. Zamani (ESA / Webb) وفريق PDRs4All ERS)]

A research team led by Dr Olivier Bernier of the University of Toulouse found that d203-506 is a methyl cation (CH3⁺) “As a result of a search the molecular ion was detected.

According to STScI, this is the first time that methyl cations have been detected in a protoplanetary disk, where planets that could support life in the future could have formed. Methyl cations do not easily interact with hydrogen, which is abundant in space, but they do interact easily with other molecules, a substance that has been considered since the 1970s. However, unlike many other molecules detected in protoplanetary disks to date, methyl cations cannot be detected by radio telescopes. Although it could theoretically have been detected by infrared observations, the Earth’s atmosphere would prevent this, so it was possible to detect it for the first time only with the advent of the highly sensitive Webb Space Telescope, which specializes in infrared observations. time.

Not only do data from the Webb Space Telescope indicate that ultraviolet light may be involved in the production of methyl cations, but also that the length of time that the protoplanetary disk is exposed to ultraviolet light may affect the chemistry of the disk. For example, no water molecules were detected in disk d203-506 where methyl cations were detected, but a significant amount of water molecules were detected in another protoplanetary disk that was not exposed to ultraviolet light.

This result, which once again proves the performance of the Webb Space Telescope, shows that methyl cations are interstellar chemistry.（※2）It is attracting attention as evidence that it plays a central role in it. Images of the Orion Nebula and d203-506 taken with the Webb Space Telescope by STScI and the European Space Agency (ESA) were released on June 26, 2023.

* 2 … Chemistry describing important interstellar chemical reactions and evolution of interstellar molecules in interstellar space (Adapted from the “Astronomical Dictionary” of the Astronomical Society of Japan)

source

• Image credit: ESA/Webb, NASA, CSA, M. Zamani (ESA/Webb), PDRs4All ERS Team
• STScI Webb makes the first discovery of the crucial carbon molecule
• ESA/web Webb makes the first detection of an important carbon molecule in a planet-forming disk

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