By Ana Margarita Gómez, Mariel Romero Muñoz, and Javier Eugenio Icaza | CIENCIA AMATEUR
Reviewing authors: Edgar André Ramírez Alonso and Alejandro Parra Córdova.
A molecule can have a kind of “right hand” and “left hand”: two forms that are mirror images of each other but cannot be superimposed. These forms, known as chiral, are of particular interest to astrobiology because life on Earth shows a strong preference for one of these two forms.
This phenomenon, known as homochirality, raises a fundamental question about the origin of life: How did nature come to favor one of these two molecular forms, and what connection might this have to the emergence of the first organisms? [1]
The projects *“Simultaneous search of five chiral molecules in Orion KL (OMC-1)” and “Exploración de cinco moléculas quirales de interés astrobiológico en la nube molecular de Orión KL (OMC-1)” investigated five chiral compounds of astrobiological interest—propylene oxide, α-aminoethanol, glyceraldehyde, 2-aminopropionitrile, and cyanooxirane—in Orion Kleinmann–Low (Orion KL), a star-forming region within the OMC-1 molecular cloud known for its extraordinary chemical richness [2].
These compounds cannot be observed directly. Instead, astronomers identify them through the spectral fingerprints they leave in radiation. Each can emit or absorb radiation at specific frequencies as its bonds and structure rotate and vibrate. Together, these frequencies form a spectral pattern that acts, in a way, like a molecular fingerprint.
Astrobiological molecules: How do we find them?
Looking for life in space is a long way from looking for living organisms. It means searching for molecules that could have been part of the chemistry that preceded life. In this case, the goal was to determine whether any of the five chiral molecules could be identified in Orion KL from the signals they leave in radiation.
The researchers compared theoretical fingerprints with real archival observations collected by the Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope in Chile. To generate the expected fingerprints for each compound, they produced synthetic spectra under Local Thermodynamic Equilibrium (LTE) conditions using CASSIS software and spectroscopic data from the Cologne Database for Molecular Spectroscopy (CDMS) and the Jet Propulsion Laboratory (JPL).
The theoretical spectra were then compared with signals detected by ALMA. CARTA, a software tool for analyzing and visualizing radio astronomy data, allowed the team to examine the observations and zoom in on regions where the compounds were expected to produce detectable signals.
The basic idea sounds simple: if a molecule is expected to produce a spectral line at a particular frequency and the telescope detects a peak there, the molecule could be present. But Orion KL turns that task into a genuine puzzle. The region contains an enormous number of molecular species, so many spectral lines overlap.
That means a single peak may be produced by more than one molecule, and an isolated match is not enough to establish that a particular species is present.
The findings
Propylene oxide showed the strongest evidence. Several of its spectral transitions matched signals detected by ALMA, making it the most promising candidate for further analysis. The researchers also found signals consistent with some transitions from α-aminoethanol and glyceraldehyde, but the matches were less conclusive and could also be explained by other molecular species.
By contrast, cyanooxirane and 2-aminopropionitrile did not produce signals clear enough to be considered candidates. This does not mean that these compounds are absent from Orion KL or that they do not exist elsewhere in space. It simply means the data analyzed do not provide enough evidence to identify them.
(a) Region 145.08–145.105 GHz, showing limited alignment with the predicted transitions, including those of glyceraldehyde and aminoethanol, with no conclusive assignment due to the weak agreement and possible overlap.
(b) Region 145.11–145.14 GHz, where several predicted transitions show better alignment with the observed spectral peaks, particularly for glyceraldehyde and propylene oxide. (Prepared by Ana Margarita Gómez, Mariel Romero Muñoz, and Javier Eugenio Icaza.)
New observations
This distinction is crucial in molecular astronomy: a match is not enough to confirm a molecule is present, but its absence from the data does not mean the molecule does not exist.
The search for the “molecule of life” is still far from a definitive answer. At this stage, it has led to a better question: Which molecules can survive, form, or transform within the clouds where stars and planets are born?
Answering that question will require new observations, better models, and many more spectral lines. But every match, every ambiguous signal, and every unidentified peak may be another piece of the same puzzle: understanding how cosmic chemistry may have prepared the stage for life.
References
- McGuire, B. A., Carroll, P. B., Loomis, R. A., Finneran, I. A., Jewell, P. R., Remijan, A. J., & Blake, G. A. (2016). Discovery of the interstellar chiral molecule propylene oxide (CH₃CHCH₂O). Science, 352(6292), 1449–145
- Cunningham, M. R., Jones, P. A., Godfrey, P. D., Cragg, D. M., Bains, I., Burton, M. G., … & Shobbrook, R. (2007). A search for propylene oxide and glycine in Sagittarius B2 (LMH) and Orion KL. Monthly Notices of the Royal Astronomical Society, 376(3), 1201–1210.
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Scientific Forums
Los resultados del proyecto para rastrear estas moléculas astrobiológicas se presentaron en dos foros científicos: el TecScience Summit 2026, en el marco de Next-Gen Scientist, y la reunión de la American Chemical Society en Atlanta.
- Romero-Muñoz, M., Icaza-Ojeda, J. E., Gómez-Romo, A. M., Ramírez-Alonso, E. A., & Parra-Córdova, A. «Exploración de cinco moléculas quirales de interés astrobiológico en la nube molecular de Orión KL (OMC-1)». Tecnológico de Monterrey, NextGen Scientist Program. TecScience Summit 2026.
- Gómez-Romo, A. M., Romero-Muñoz, M., Icaza-Ojeda, J. E., Parra-Córdova, A. & Ramírez-Alonso, E. A. «Simultaneous search of five chiral molecules in Orion KL (OMC-1)», American Chemical Society Meeting.
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Authors
Ana Margarita Gómez. Chemical engineer from Tecnológico de Monterrey and a Chemistry undergraduate at the University of Guadalajara.
Mariel Romero Muñoz. Biotechnology engineer from Tecnológico de Monterrey, with honors and recipient of the Ceneval National Award.
Javier Eugenio Icaza Ojeda. Chemical engineer from Tecnológico de Monterrey.
Article supervised by Edgar André Ramírez Alonso and Alejandro Parra Córdova, faculty members in the Department of Sciences (School of Engineering and Sciences at Tecnológico de Monterrey, Guadalajara Campus).
