The Largest Alcohol Molecule Found in Space Yet Could Be The Key to Star Formation

The Largest Alcohol Molecule Found in Space Yet Could Be The Key to Star Formation ...

There's alcohol up in space. It's not bottles of wine that are discarded by uninformed astronauts; it's in microscopic molecular form. Researchers now believe they've discovered the largest alcohol molecule in space yet, in the form of propanol.

Propanol molecules are present in two forms, or isomers, both of which have been identified in observations for the first time: normal-propanol, which has been identified in a star-forming region, and iso-propanol, the key ingredient in hand sanitizer, which has never been seen in interstellar form previously.

These findings should shed light on the formation of celestial bodies such as comets and stars.

"Because they are so similar, they behave physically in very similar ways," says University of Virginia astrochemist Rob Garrod.

"The only open question is the exact quantities that are present." This allows their interstellar ratios to be much more precise than would be the case for other molecules. It also means that the chemical network can be tuned much more attentively to determine the mechanisms by which they form.

These alcohol molecules were discovered in what's known as a'delivery room' of stars, Sagittarius B2 (Sgr B2), which forms near the Milky Way's center and close to Sagittarius A*, the huge black hole that our galaxy is built around.

Although this kind of deep space research has been ongoing for more than 15 years, the arrival of the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile ten years ago has increased the degree of detail that astronomers may access.

ALMA has a higher resolution and greater sensitivity, enabling researchers to detect molecules that were previously invisible. It's crucial to be able to discern what's out there in a busy area like Sgr B2.

"The larger the molecule, the more spectral lines it produces," says physicist Holger Muller of the University of Cologne in Germany. "In a source such as Sgr B2, there are so many molecules contributing to the observed radiation that their spectra overlap, and it is difficult to distinguish them individually."

The discovery was made due to ALMA's ability to detect very small spectral lines, as well as research that detailed the signatures that propanol isomers would be giving off in space.

Scientists may look into the chemical reactions that have resulted in molecules that are closely linked, such as normal-propanol and iso-propanol.

ALMA continues to investigate more interstellar molecules in Sgr B2, and to understand the mechanism that leads to star formation. The organic molecules iso-propyl cyanide, N-methylformamide, and urea have also been discovered.

"In the ALMA spectrum of Sgr B2, there are still many unidentified spectral lines," says astronomer Karl Menten of the Max Planck Institute for Radio Astronomy in Germany.

"In the near future, the reduction of the ALMA instrumentation down to lower frequencies will likely help us to reduce the spectral confusion even further and possibly allow the identification of additional organic molecules in this spectacular source."

The research has been published in Astronomy & Astrophysics here and here.

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