Precursor substances of life discovered in the Perseus Cloud

Numerous prebiotic substances have been discovered in the IC 348 star-forming region of the Perseus Molecular Cloud, a young star cluster 2 to 3 million years old.

The finding was made by researchers Susana Iglesias-Groth, from the Instituto de Astrofísica de Canarias (IAC), and Martina Marin-Dobrincic, from the Polytechnic University of Cartagena, both institutions in Spain.

Some of the biomolecules detected are considered essential building blocks for more complex molecules such as amino acids, which shaped the genetic code of ancient microorganisms and allowed life to thrive on Earth. Knowing the distribution and abundances of these precursor molecules in regions where, most likely, planets are forming is one of the biggest challenges in astrophysics.

The Perseus Cloud is one of the closest star-forming regions to our solar system. Many of its stars are young and contain protoplanetary disks in which the physical processes that give rise to planets take place. “It is an extraordinary organic chemistry laboratory,” explains Iglesias-Groth, who, in 2019, found fullerenes in the same molecular cloud, pure carbon molecules that frequently appear as building blocks of key molecules for life.

Now, the new research has managed to detect, in the inner part of this region of the sky, common molecules such as molecular hydrogen (H2), hydroxyl (OH), water (H2O), carbon dioxide (CO2) and ammonia (NH3), as well as several carbonaceous molecules that can play an important role in the production of more complex hydrocarbons and prebiotic molecules, such as hydrogen cyanide (HCN), acetylene (C2H2), diacetylene (C4H2), cyanoacetylene (HC3N), cyanobutadiene (HC5N) , ethane (C2H6), hexatrin (C6H2) and benzene (C6H6).

Artist’s composition of a “soup” of prebiotic molecules around a protoplanetary disk. (Image: Gabriel Pérez Díaz (IAC). CC BY)

The data also shows the presence of more complex molecules such as polycyclic aromatic hydrocarbons (PAHs) and C60 and C70 fullerenes. “IC 348 appears to be very rich and diverse in molecular content,” says Iglesias-Groth. The novelty is that we see the molecules in the diffuse gas from which stars and protoplanetary disks are forming.

The presence of prebiotic molecules in interstellar locations so close to the core of this star cluster suggests the possibility that accretionary processes are taking place on young planets that could contribute to the formation of complex organic molecules. “These key molecules could have been brought to the nascent planets in the protoplanetary disks and could thus pave the way for the molecules of life in them”, emphasizes Marin-Dobrincic.

The detection made by the two researchers is based on data taken with NASA’s Spitzer astronomical satellite. The next step will be to use the powerful James Webb Space Telescope (JWST). “The spectroscopic capabilities of the JWST will be able to provide details on the spatial distribution of all these molecules and extend the present search to other more complex ones, providing greater sensitivity and resolution, essential to confirm the very probable presence of amino acids in the gas of this and other star-forming regions”, concludes Iglesias-Groth.

The study is titled “A rich molecular chemistry in the gas of the IC 348 star cluster of the Perseus Molecular Cloud”. And it has been published in the academic journal Monthly Notices of the Royal Astronomical Society. (Source: IAC)