Unexplained radiation in space may come from Fullerenes

A C60 buckyball and some of its positive ions along with some of the spectral lines thought to be associated with it

The C60 buckyball and some of its highly positively charged cations have been proposed as the Solar System, representing theoretically calculated normal modes of vibrational motions and relative molecular sizes (volumes). Image Credit: SeyedAbdolreza Sadjadi and Quentin Andrew Pa

Most of our knowledge of the composition of the universe stems from the fact that molecules emit and absorb radiation at different wavelengths. However, the molecules associated with certain wavelengths have yet to be identified — despite decades of work, in some cases. New research links some of these mysterious wavelengths to fullerene ions, which were once thought to be purely artificial molecules. More speculative research associates other unexplained spectral lines with fullerene metal complexes. If so, these would be the largest molecules found in space to date.

After spectroscopy (the science of interpreting electromagnetic spectra) was invented, it was natural to apply it to the light from the sun. During the solar eclipse of 1868, several astronomers have independently noted spectral lines at wavelengths not associated with any known element. The search for an explanation led chemists to discover: helium.

We are now familiar with the spectral lines of all elements that can occur in nature, plus quite a few that only occur in laboratories. Nevertheless, molecules can produce spectral lines that differ from the single atoms that make up them. The astrophysics magazine contains a possible explanation for lines that astronomers have not been able to match with a molecule since they were first observed in the 1970s. Particularly puzzling were those at 11.21, 16.40 and 20-21 micrometers, all in the mid-infrared and at the heart of JWST‘s range. Most speculation has associated these rules with unspecified polycyclic aromatic hydrocarbons (PAHs).

Buckminsterfullerene C60 (commonly abbreviated to buckyball or fullerene) is a nearly spherical molecule of 60 carbon atoms, connected in hexagonal rings. When exposed to ultraviolet light, it can repel a remarkable number of electrons, keeping the resulting ions stable.

Theoretical Modeling previously published by means of dr. Seyed Abdolreza Sadjadic and Professor Quentin Parker from the University of Hong Kong suggests that fullerenes should be stable in space up to 26+ (i.e. the loss of 26 electrons), although highly charged versions react with hydrogen where it is abundant. Each ion has slightly different spectral lines, and the new paper by Sadjadi and Parker (and co-authors) predicts those produced by these highly positive fullerene ions.

“This work shows that the infrared emission characteristics of such species are an excellent match for some of the most prominent unidentified infrared emission characteristics known,” Parker said in a statement. pronunciation.

Fullerenen is often said to resemble the shape of a (soccer) football, and Sadjadi compared his earlier work; “Asking how much air you can push out of a soccer ball and the ball will still hold its shape.”

Spectral wavelengths are sometimes explained by an analogy with notes on a piano keyboard. The new newspaper, Sajadi said, searched for; “Determine the molecular vibrational tones of a celestial symphony, that is, the spectral features these ionized buckyballs would play/produce.”

The authors then linked the wavelengths they identified to unexplained spectral lines emanating from planetary nebulae.

The fullerene-associated wavelengths 17.4 and 18.9I have been previously identified in planetary nebulae, so we know they are produced by stars when they die. In the pre-print from an unpublished article dr. Gao-Lei Hou from KU Leuven, Belgium continues.

Hou and co-authors produced complexes of fullerenes and common metals such as lithium, sodium and iron. They measured their spectral lines and matched them with others observed in planetary nebulae that previously did not match known molecules. Unlike fullerenes themselves, these buckyball metal complexes have not been previously known to exist in space. if [C60-metal]+ ions responsible for these lines would be the largest molecules we have ever observed in gas clouds.

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