Astronomers Found a Rare Form of Alcohol in Space. There’s Far More Than Expected

A strange molecule around a young star reveals a missing piece of interstellar chemistry.

19 Oct 2026, 18:39 by Tibi Puiu · ZME Science

The Perseus molecular cloud is located about 1,000 light-years from Earth. A rare form of the organic alcohol methanol is present around at least one of the very young stars still embedded within it. The molecule has been detected in space for the first time ever in the current study. Credit: Ekaterina Moerova / MPIfR; Background: NASA, CXC, SSC, NOAO, DSS.

In a stellar nursery about 1,000 light-years from Earth, astronomers have found a form of alcohol in which all four hydrogen atoms have been replaced by heavier versions of themselves.

Scientists had actually searched for this peculiar molecule for years. Now they have found it beyond doubt. So, you’d think this would be cause to celebrate.

But there’s a problem. The molecule is far more abundant than existing theories can explain.

The substance in question is fully deuterated methanol, a rare relative of wood alcohol (methanol used to come by this name because it was historically produced through the destructive distillation of wood by heating wood chips or boxwood in the absence of air).

The discovery of wood alcohol in a far-off world beyond the Sun is a rare opportunity to study the chemistry that unfolds in the frigid clouds where stars and planets take shape. The findings, published in Astronomy & Astrophysics, suggest that scientists are missing something fundamental about how complex organic molecules form in space. Otherwise, the computer models would have agreed fully with the actual observations.

Methanol is a relatively simple molecule with an outsized role in cosmic chemistry. It helps produce more elaborate carbon-containing compounds, including some relevant to the chemistry of life. Much of it forms before a star is born, when carbon monoxide and hydrogen react on the icy surfaces of microscopic dust grains.

As a young star warms its surroundings, molecules trapped in ice escape into the gas, where powerful radio telescopes can detect them.

Ordinary methanol (CH₃OH) contains four hydrogen atoms. Deuterium, sometimes called heavy hydrogen, has an extra neutron in its nucleus. Replace one hydrogen atom with deuterium and the molecule becomes slightly heavier. Replace all four, and you get CD₃OD, the molecule astronomers have now conclusively identified in interstellar space for the first time.

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Ten Chemical Fingerprints

Illustration showing the chemical structures of complex organic molecules discovered in a planet-forming disk. Credit: ESO/L. Calçada/T. Müller (MPIA/HdA).

The research team, led by Arnaud Belloche of the Max Planck Institute for Radio Astronomy in Germany, used the Atacama Large Millimeter/submillimeter Array (ALMA), a network of radio antennas in Chile.

Through a survey called COMPASS, the astronomers examined 11 young stellar systems known to contain complex organic molecules.

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One stood out: IRAS4A2, part of a developing double-star system in the Perseus molecular cloud, located some 1,000 light-years away.

Different molecules emit radio waves at characteristic frequencies, creating signatures that astronomers can recognize like fingerprints. The researchers identified 10 convincing spectral lines matching fully deuterated methanol, enough to distinguish it from the crowded background of other molecular signals.

There had been tantalizing hints that this form of methanol is found on distant worlds. A 2023 study found possible signatures of the same molecule around another young stellar system, IRAS 16293-2422, but lacked sufficient evidence to confirm it.

The new observations finally settle the question.

“Deuteration enables us to trace the chemical evolution of molecules during the formation of stars and planets,” said Silvia Spezzano, a co-author at the Max Planck Institute for Extraterrestrial Physics.

The reason is that when temperatures plunge in the gas and dust clouds where stars form, deuterium becomes much more likely to replace ordinary hydrogen in certain molecules. This makes it a useful chemical clue. By measuring how much deuterium a molecule contains, scientists can learn about the cold conditions in which it formed, long before a newborn star began heating its surroundings.

A Hundred Times Too Much, or Even More

The real surprise came when the researchers measured how much of each methanol variety existed around IRAS4A2.

They estimated that there were roughly four fully deuterated methanol molecules for every 10,000 ordinary methanol molecules.

Measuring the difference wasn’t straightforward. Ordinary methanol produces such strong radio signals that astronomers can underestimate how much is actually there. The team accounted for this by using rarer forms of methanol as a guide.

Even after that correction, the numbers refused to add up.

Some chemical models predicted roughly 100 times less heavily deuterated methanol than the astronomers observed. One model missed the mark by a staggering 100,000-fold for the fully deuterated form.

The message was clear: something important is missing from our understanding of how these molecules form in space. And the more deuterium atoms a methanol molecule contains, the harder it becomes for existing models to explain its abundance.

Lab experiments performed by the researchers luckily offered some clues. Certain chemical reactions replace hydrogen with deuterium, and once deuterium becomes incorporated into methanol, some reactions remove it less readily. Yet even models incorporating such processes fail to account for all facets of the observations.

“A key process driving the formation of multiply deuterated methanol therefore seems to be missing from all of them,” Belloche explained.

The ALMA data may hold more surprises. The researchers identified several unexplained radio signals that could belong to two other forms of multiply deuterated methanol. Laboratory measurements must establish their precise spectral fingerprints before astronomers can confirm them.

The discovery joins a growing inventory of organic chemistry in space. In 2012, astronomers detected glycolaldehyde, a simple sugar-related molecule, around a young Sun-like star. In 2025, samples returned from asteroid Bennu revealed amino acids and other ingredients relevant to life.

None of these findings constitutes evidence of extraterrestrial life. But they show how chemically rich the environments that eventually produce planets can become.