An international team has detected five complex organic molecules trapped in the ice around a protostar identified as ST6, located in Grande Nuvem of Magalhães about 160,000 light-years away. The discovery, made by Telescópio Espacial James Webb, marks the first time that compounds of this nature have been identified in a solid state outside of Via Láctea. The findings open new perspectives on prebiotic chemistry in the universe’s most austere chemical environments.
Cinco compounds discovered in frozen ice sheets
Molecules identified in the infrared spectrum include methanol, ethanol, acetaldehyde, methyl formate and acetic acid, all of which coat interstellar dust grains. James Webb’s MIRI instrument (Infrared Medium Range Imaging) provided the sensitivity needed to separate overlapping signals that previous telescopes were unable to discriminate. The region’s extreme temperatures, around 20 Kelvin, equivalent to approximately −250 °C, created ideal conditions for the preservation of these ices.
Acetic acid emerged as a special highlight of the discovery. Trata is the first detection of this molecule in solid form in space, in any environment observed to date. The simultaneous presence of multiple organic compounds indicates that efficient chemical reactions occur on grain surfaces even under extremely adverse conditions.
Spectral Análise reveals molecular fingerprints
Mid-infrared spectra capture the specific vibrations of chemical bonds in each molecule. Quando these atoms vibrate, absorbing light at particular wavelengths, creating unique patterns similar to fingerprints. The resolution of the James Webb allowed us to transform a single spectrum into a detailed chemical inventory.
The team also detected spectral clues consistent with glycolaldehyde, a chemically related precursor to ribose, although this identification still requires confirmation with more specific data. If verified, the discovery would reinforce scenarios in which molecular components linked to sugars can be generated in ice sheets even before the formation of planets.
- Metanol (CH3OH): fundamental starting point for larger organic structures
- Etanol (C2H5OH): evidence of efficient reactions between carbon and oxygen
- Acetaldeído (CH3CHO): intermediate in sugar synthesis pathways
- Methyl Formiato (HCOOCH3): associated with reactions during heating
- Acetic Ácido (CH3COOH): first solid-state detection
Hostile Ambientes still produce complex chemistry
Grande Nuvem of Magalhães exhibits features that have historically challenged traditional astrochemical models. Metal-poor Sendo, that is, containing fewer heavy elements such as carbon, nitrogen and oxygen than Via Láctea, its chemical complexity was expected to be limited. Além Furthermore, the ST6 protostar is located within an energetic superbubble called N158, a region of intense ultraviolet radiation capable of destroying fragile molecules.
The discovery of sophisticated organic compounds in this hostile environment demonstrates that the surfaces of dust grains function simultaneously as a shelter and a chemical factory. Ice sheets protect fragile molecules from destructive radiation while providing surfaces that make reactions more efficient. Cosmic Raios, weak heating, and ultraviolet photons, in gradual combination, initiate a radical chemistry that builds up over time.
Two-phase organic synthesis Ciclo
Astrochemistry traditionally describes how chemistry occurs in two sequential steps. Primeiro, simple species—water, carbon monoxide, and methanol, are deposited and form successive layers of ice. Then, moderate energy sources activate the mobility of atoms and radicals within these layers, allowing carbon, oxygen and hydrogen to rearrange into larger structures.
Conforme the protostar shines and heats the surrounding region, part of the ice mantle is released into the gaseous phase, seeding the environment with complex organic compounds. Esse process has been extensively documented in Via Láctea in multiple protostars during heating phases. The observation in ST6 extends this mechanism to a more chemically austere environment, suggesting that similar processes may be universal in the early stages of star formation.
Trajetória of Prebiotic Ingredients from Starbirth
The strategic importance of this discovery lies in its timing. The molecules were detected during the protostar’s infancy, long before the formation of planetary disks. If such organic ices were abundant and common in protostars, drifting ice-rich solids could transport preexisting organic matter to planet-forming regions. Cometas and planetesimals would later redistribute this material to developing worlds.
Esse scenario corroborates evidence obtained from comets in the solar system. Amostras and cometary coma spectra show robust families of complex organic compounds. The link between ices around distant protostars and the chemical inventory of nearby comets reinforces the idea of a continuous chemical supply chain, starting at stellar birth and ending at planetary surfaces.
Próximas observations will expand astrochemical mapping
The team intends to expand the study to other protostars in Nuvens and Magalhães. A larger sample will reveal how often these ices appear, how their abundances vary between objects, and which specific environments favor particular molecules. Observações using radio interferometers will connect solid-state stores with gas-phase releases as regions warm.
The study was published on October 20, 2025 in the journal Astrophysical Journal Letters. The methodology used mid-infrared spectroscopy from the MIRI instrument to separate overlapping spectral features. The distance to Grande Nuvem from Magalhães and the presence of highly active star-forming nuclei made this region an ideal testing ground for understanding chemistry under low-metallicity conditions.