This artist’s impression shows the planet-forming disc around the star V883 Orionis. In the outermost part of the disc, volatile gases are frozen out as ice, which contains complex organic molecules. An outburst of energy from the star heats the inner disc to a temperature that evaporates the ice and releases the complex molecules, enabling astronomers to detect it. The inset image shows the chemical structure of complex organic molecules detected and presumed in the protoplanetary disc (from left to right): propionitrile (ethyl cyanide), glycolonitrile, alanine, glycine, ethylene glycol, and acetonitrile (methyl cyanide). Credit: ESO/L. Calçada/T. Müller (MPIA/HdA)
Astronomers have discovered signs of complex organic molecules, considered precursors to sugars and amino acids, within a planet-forming disc.
Using the powerful Atacama Large Millimeter/submillimeter Array (ALMA), a research team led by Abubakar Fadul from the Max Planck Institute for Astronomy (MPIA) has identified a variety of complex organic molecules within the protoplanetary disc surrounding the outbursting protostar V883 Orionis. Among the 17 compounds detected were ethylene glycol and glycolonitrile, both seen for the first time in this type of environment. These molecules are thought to be early chemical ingredients that contribute to the formation of life.
The discovery adds to a growing body of evidence that suggests life’s building blocks originate in space. By comparing different regions across the cosmos, researchers have observed that the concentration and diversity of complex molecules increase as systems evolve from early star-forming clouds into mature planetary systems. This pattern supports the idea that the raw materials needed for life may be commonly produced in space and distributed widely across the universe. The team’s findings have been published in the Astrophysical Journal Letters.
Astronomers have previously found complex organic molecules (COMs) in areas linked to star and planet formation. These molecules contain more than five atoms, including at least one carbon atom, and often represent early forms of life-supporting chemicals like amino acids and nucleic acids. The new detection of 17 COMs in V883 Orionis offers an important insight into how these compounds evolve between the early stages of star formation and the development of planets. Among them, glycolonitrile is especially significant because it serves as a chemical precursor to glycine and alanine (both amino acids), as well as adenine, a nucleobase found in DNA.
The assembly of prebiotic molecules begins in interstellar space
“Our finding points to a straight line of chemical enrichment and increasing complexity between interstellar clouds and fully evolved planetary systems,” says Abubakar Fadul, MPIA
The transition from a cold protostar to a young star surrounded by a disc of dust and gas is accompanied by a violent phase of shocked gas, intense radiation, and rapid gas ejection.
Such energetic processes might destroy most of the complex chemistry assembled during the previous stages. Therefore, scientists had laid out a so-called ‘reset’ scenario, in which most of the chemical compounds required to evolve into life would have to be reproduced in circumstellar discs while forming comets, asteroids, and planets.
“Now it appears the opposite is true,” MPIA scientist and co-author Kamber Schwarz points out. “Our results suggest that protoplanetary discs inherit complex molecules from earlier stages, and the formation of complex molecules can continue during the protoplanetary disc stage.” Indeed, the period between the energetic protostellar phase and the establishment of a protoplanetary disk would, on its own, be too short for COMs to form in detectable amounts.
As a result, the conditions that predefine biological processes may be widespread rather than being restricted to individual planetary systems.
Astronomers have found the simplest organic molecules, such as methanol, in dense regions of dust and gas that predate the formation of stars. Under favourable conditions, they may even contain complex compounds comprising ethylene glycol, one of the species now discovered in V883 Orionis. “We recently found ethylene glycol could form by UV irradiation of ethanolamine, a molecule that was recently discovered in space,” adds Tushar Suhasaria, a co-author and the head of MPIA’s Origins of Life Lab. “This finding supports the idea that ethylene glycol could form in those environments but also in later stages of molecular evolution, where UV irradiation is dominant.”
More evolved agents crucial to biology, such as amino acids, sugars, and nucleobases that make up DNA and RNA, are present in asteroids, meteorites, and comets within the Solar System.
Buried in ice – resurfaced by stars
The chemical reactions that synthesize those COMs occur under cold conditions, preferably on icy dust grains that later coagulate to form larger objects. Hidden in those mixtures of rock, dust, and ice, they usually remain undetected. Accessing those molecules is only possible either by digging for them with space probes or by external heating, which evaporates the ice.
In the Solar System, the Sun heats comets, resulting in impressive tails of gas and dust, or comas, essentially gaseous envelopes that surround the cometary nuclei. This way, spectroscopy – the rainbow-like dissection of light – may pick up the emissions of freed molecules. Those spectral fingerprints help astronomers to identify the molecules previously buried in ice.
A similar heating process is occurring in the V883 Orionis system. The central star is still growing by accumulating gas from the surrounding disc until it eventually ignites the fusion fire in its core. During those growth periods, the infalling gas heats up and produces intense outbursts of radiation. “These outbursts are strong enough to heat the surrounding disc as far as otherwise icy environments, releasing the chemicals we have detected,” explains Fadul.
“Complex molecules, including ethylene glycol and glycolonitrile, radiate at radio frequencies. ALMA is perfectly suited to detect those signals,” says Schwarz. The MPIA astronomers were awarded access to this radio interferometer through the European Southern Observatory (ESO), which operates it in the Chilean Atacama Desert at an altitude of 5,000 metres. ALMA enabled the astronomers to pinpoint the V883 Orionis system and search for faint spectral signatures, which ultimately led to the detections.
Further challenges ahead
“While this result is exciting, we still haven’t disentangled all the signatures we found in our spectra,” says Schwarz. “Higher resolution data will confirm the detections of ethylene glycol and glycolonitril and maybe even reveal more complex chemicals we simply haven’t identified yet.”
“Perhaps we also need to look at other regions of the electromagnetic spectrum to find even more evolved molecules,” Fadul points out. “Who knows what else we might discover?”
Reference: “A Deep Search for Ethylene Glycol and Glycolonitrile in the V883 Ori Protoplanetary Disk” by Abubakar M. A. Fadul, Kamber R. Schwarz, Tushar Suhasaria, Jenny K. Calahan, Jane Huang and Merel L. R. van ’t Hoff, 24 July 2025, The Astrophysical Journal Letters.
