Basic building block for organic chemistry discovered for the first time in forming planets

The James Webb space telescope has discovered an important basic building block for organic chemistry in a protoplanetary disk for the first time and has thus probably solved a mystery. The Space Telescope Science Institute, which is responsible for research, has now made this public. In the protoplanetary disc d203-506, 1350 light-years away, the trace of the molecule CH₃⁺ proven. This “methyl cation” reacts comparatively inefficiently with hydrogen and much better with other molecules. It thus stimulates the growth of carbon-based molecules and, according to our current understanding, stands at the beginning of organic chemistry, which includes all the building blocks of life.

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Helpful UV radiation

Carbon compounds are of particular interest in the search for extraterrestrial life because all life forms known to us are based on them. That with CH₃⁺ Now that a basic building block has been discovered in a star system in which planets are still being formed is particularly exciting. At the same time, however, the space telescope also determined that the molecule is present there, even though the system is being bombarded with ultraviolet radiation from nearby hot young stars. Until now it was assumed that such radiation destroys all complex organic molecules. However, the find now suggests that the radiation is responsible for the formation of CH₃⁺ on the contrary, it is even needed, because it probably supplies the necessary energy.

While a wide variety of substances and molecules have already been detected in so-called protoplanetary disks, for CH₃⁺ so far not possible explains the research team. This is because its trace can only be found in the infrared spectrum. But that is swallowed up by the Earth’s atmosphere, so ground-based observatories are blind to it. The find was only possible with the new space telescope. Thanks to the great precision of the new instrument, extensive preparatory work and the cooperation of different research directions, the proof even then only took a few weeks. It is now being presented in the science magazine Nature.

The discovery that ultraviolet radiation can so alter conditions in a star system has far-reaching implications for our understanding of the history of our own homeland and for the search for extraterrestrial life. Analyzes of meteorites have therefore already suggested that the solar system was also exposed to such massive UV radiation at the beginning of its formation. This could have been responsible for the formation of the simplest carbon compounds. At the same time, however, the James Webb Space Telescope (JWST) found that protoplanetary disks without such radiation are rich in water. No trace at all of this was found in d203-506.

Operated by space agencies NASA, ESA and CSA, JWST was launched on December 25, 2021. After unfolding itself in a complex procedure, it arrived at its place of use a month later. Here it looks away from the sun, earth and moon into space so that their thermal radiation does not disturb the infrared telescope. A huge protective screen blocks them. For months, researchers have been impressed by the data collected with it, and new finds are presented regularly. In just a few days it will be the anniversary of the start of scientific operations.

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(mho)