Astronomers have detected a variety of complex organic molecules (COMs) in the protoplanetary disk surrounding a young star, offering compelling new clues about the chemical roots of life. Using the Atacama Large Millimeter/submillimeter Array (ALMA), a team led by Abubakar Fadul of the Max Planck Institute for Astronomy (MPIA) identified 17 complex compounds in the disk of V883 Orionis.
Organic Complexity Preserved Through Stellar Evolution
These molecules, considered precursors to life’s building blocks, add a crucial piece to a puzzle that scientists have been trying to complete for decades — the transition of simple compounds formed in interstellar clouds to biologically relevant chemistry on young planets.
Traditionally, scientists proposed a “reset scenario,” assuming that high-energy processes around a forming star — such as shocks, radiation, and gas ejection — destroy most of the complex molecules created earlier in space. However, Fadul’s research points in a different direction. According to the study, “our finding points to a straight line of chemical enrichment and increasing complexity between interstellar clouds and fully evolved planetary systems.”
Co-author Kamber Schwarz adds that “our results suggest that protoplanetary disks inherit complex molecules from earlier stages, and the formation of complex molecules can continue during the protoplanetary disk stage.”
Among the 17 compounds detected in V883 Orionis were glycolonitrile, a known precursor to amino acids like glycine and alanine, as well as the nucleobase adenine. These are molecules vital to RNA and DNA, highlighting the connection between astrochemistry and biological potential. The presence of ethylene glycol, which plays a role in more advanced organic reactions, further strengthens this link.
Violent Stellar Outbursts Reveal Hidden Molecules
The detection of these complex molecules was made possible by a burst of stellar energy in the V883 Orionis system. Normally, such molecules are trapped in icy dust grains in the outer reaches of the disk, beyond the so-called snowline. But when the young star undergoes an outburst phase, gas falls onto it from the disk, generating intense heat. This energy warms the surrounding environment, evaporating ice and releasing complex molecules into the gas phase, where they become detectable.
This mechanism mirrors processes seen in our own solar system. Comets, which also harbor complex compounds, are heated as they approach the Sun, producing gaseous comas that allow their chemical makeup to be studied via spectroscopy. In both cases, external heating unveils hidden organic matter.
“Complex molecules, including ethylene glycol and glycolonitrile, radiate at radio frequencies,” says Schwarz. “ALMA is perfectly suited to detect those signals.” The observatory, operated by the European Southern Observatory (ESO) in the Chilean Atacama Desert at 5,000 meters elevation, enabled researchers to target faint emissions from V883 Orionis with exceptional precision.
Connecting Interstellar Chemistry To Life’s Origins
The presence of COMs such as methanol, acetonitrile, and propionitrile in star-forming regions has been documented before, but this new study fills an important gap. It connects these early-stage molecules to the more mature planetary building blocks found in comets, asteroids, and meteorites.
The continuity of this chemistry from interstellar clouds to planetary systems underscores a long-term pathway for molecular complexity that spans light-years and millions of years. Co-author Tushar Suhasaria, head of the MPIA’s Origins of Life Lab, explains that “we recently found that ethylene glycol could be formed by UV irradiation of ethanolamine, a molecule that was recently discovered in space.”
New Questions On The Horizon
While these discoveries are promising, researchers caution that more work is needed. “We still haven’t disentangled all the signatures we found in our spectra,” says Schwarz. Some signals require higher-resolution data to confirm, and the possibility exists that even more complex molecules remain undetected.
The team also believes that looking at other wavelength ranges in the electromagnetic spectrum might yield further surprises. “Who knows what else we might discover?” Fadul wonders, pointing toward a future where astronomers may map the full extent of cosmic prebiotic chemistry across diverse planetary nurseries.
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