# Fully deuterated methanol CD3OD detected for the first time around protostar IRAS4A2 with ALMA

- Published: 2026-11-07 15:37 UTC
- Section: Sky & Space › Astronomy
- Tags: fully deuterated methanol, CD3OD, IRAS4A2, ALMA COMPASS, Perseus molecular cloud, deuterated molecules, complex organic molecules, protostar chemistry, Max Planck Institute for Radio Astronomy
- URL: https://realtech.media/news/rt-9243a241063e8fbea333739d_fully_deuterated_methanol/

**Astronomers using ALMA found CD3OD around a young star in the Perseus cloud, about 100 times more abundant than models predict.**

![Fully deuterated methanol CD3OD detected for the first time around protostar IRAS4A2 with ALMA](https://realtech.media/media/2026/11/b7d34951201f0f80.jpg)
*mpe.mpg.de*

A team led by Arnaud Belloche at the Max Planck Institute for Radio Astronomy has detected fully deuterated methanol (CD3OD) in space for the first time, according to mpe.mpg.de. In this molecule every hydrogen atom is replaced by deuterium. It was found around the protostar IRAS4A2 in the Perseus molecular cloud, about 1000 light-years from Earth. [1] The study is published in Astronomy & Astrophysics. It is also the first detection of a quadruply deuterated interstellar molecule. [1]

## Observations with ALMA

The data come from the ALMA program COMPASS (Complex Organic Molecules in Protostars with ALMA Spectral Surveys), in which the researchers observed eleven young stellar systems. ALMA is an array of radio telescopes in the Atacama Desert in Chile. In IRAS4A2 the team identified an unambiguous signature of CD3OD. [1]

Methanol (CH3OH), the simplest organic alcohol, is a key building block of more complex molecules. Experiments suggest that such molecules form on the surface of icy dust grains long before the star ignites. When the protostar begins to shine and warms its surroundings, the compounds are released as gas, and their signatures can be observed with telescopes. [1]

Deuterated molecules form only under extremely cold conditions typical of the early stages of star formation. A complete inventory of methanol variants, from the common CH3OH through the singly and multiply deuterated forms to the fully deuterated one, helps determine which chemical pathways dominate. Until now there was a gap in observations in this area. [1]

## Abundance above model predictions

The researchers also determined the abundances of the different methanol variants. The fully deuterated form is about 100 times more abundant than theoretically predicted, and none of the available chemical models currently explains this. According to Belloche, a key process driving the formation of multiply deuterated methanol seems to be missing from all of them. [1]

The IRAS4A2 data also contain unidentified spectral lines. Given the CD3OD detection, the astronomers expect that some of them may originate from the multiply deuterated forms CH2DOD and CHD2OD. The laboratory data needed for confirmation are being prepared at the Center for Astrochemical Studies at MPE, which runs a systematic program on the spectroscopy of deuterated complex organic molecules. [1]

Co-author Silvia Spezzano, a research group leader at the Max Planck Institute for Extraterrestrial Physics, said that deuteration makes it possible to trace the chemical evolution of molecules during the formation of stars and planets, and how molecular complexity is transferred from interstellar clouds to planetary systems. Six other COMPASS studies are being published alongside this one. [1]

## Sources

1. [mpe.mpg.de](https://www.mpe.mpg.de/8208977/news20260701)
2. [t3n](https://t3n.de/news/holzalkohol-weltraum-wissenschaftler-1000-lichtjahre-1768684)

---

Source: RealTech, realtech.media — https://realtech.media/news/rt-9243a241063e8fbea333739d_fully_deuterated_methanol/