Researchers detect a new molecule in space

New research from MIT professor Brett McGuire’s team reveals the existence of a previously unknown molecule in space. The team’s open access paper “Rotation spectroscopy and first interstellar detection of 2-methoxyethanol using ALMA observations of NGC 6334I” was published in the April 12 issue of ” Astrophysical Journal Communications.

Zachary TP Fried, a graduate student in McGuire’s group and lead author of the publication, worked to assemble a puzzle composed of pieces collected from around the world, stretching from MIT to France, Florida, Virginia and Copenhagen to achieve this exciting target discovery.

“Our group is trying to understand what molecules are present in the regions of space where stars and solar systems eventually form,” Fried explained. “This allows us to piece together how chemistry evolved as stars and planets formed. We did this by looking at the rotational spectra of molecules, the unique patterns of light they emit as they tumble through space.

“These patterns are fingerprints (barcodes) of molecules. In order to detect new molecules in space, we first have to understand what molecule we want to look for, then we can record its spectrum in a laboratory on Earth, and finally we use telescopes to look for it. Spectrum in space.

Searching for molecules in space

The McGuire Group has recently begun using machine learning to suggest good target molecules. In 2023, one of the machine learning models revealed that the researchers were targeting a molecule called 2-methoxyethanol.

“There are many ‘methoxy’ molecules in space, such as dimethyl ether, methoxymethanol, ethyl methyl ether and methyl formate, but 2-methoxyethanol will be the largest and most powerful one ever seen. Complex molecules,” Fried said.

To detect the molecule using radio telescope observations, the team first needed to measure and analyze its rotational spectrum on Earth. The researchers combined experiments at the University of Lille (Lille, France), the New College of Florida (Sarasota, Florida), and MIT’s McGuire Laboratory to measure the spectrum in a broad region from microwaves to submillimeter frequencies. Wave state (approximately 8 to 500 GHz).

The data collected from these measurements allowed the search for molecules using Atacama Large Millimeter/submillimeter Array (ALMA) observations of two separate star-forming regions (NGC 6334I and IRAS 16293-2422B). Members of McGuire’s team analyzed these telescopic observations along with researchers at the National Radio Astronomy Observatory (Charlottesville, Virginia) and the University of Copenhagen, Denmark.

“Ultimately, we observed 25 rotational lines of 2-methoxyethanol that aligned with the molecular signal (barcode match) observed for NGC 6334I, allowing safe detection of 2-methoxyethanol in this source. Fried said. “This allows us to derive physical parameters of the NGC 6334I molecule, such as its abundance and excitation temperature. It also enables the study of possible chemical formation pathways of known interstellar precursors.”

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Molecular discoveries like this help researchers better understand the development of molecular complexity in space during star formation. 2-Methoxyethanol contains 13 atoms, which is quite large by interstellar standards. , and all exist in cyclic structures.

“Continuous observation of macromolecules and subsequent derivation of their abundance allows us to further understand how efficiently macromolecules are formed and by which specific reactions they may be produced,” Fried said.

“In addition, because we detected this molecule in NGC 6334I but not in IRAS 16293-2422B, we had a unique opportunity to study how the different physical conditions of the two sources affect the chemistry that may occur. reaction.

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