Molecular Precursors of Life Discovered in the Perseus Cloud

Artist’s rendering of a “shoulder” of prebiotic molecules around a protoplanetary disk. Credit: Gabriel Pérez Díaz (IAC)

A study led by researcher Susana Iglesias of the Instituto de Astrofísica de Canarias has revealed the presence of large amounts of complex organic molecules in one of the closest star-forming regions to the Solar System. The results of this have been published in the journal Monthly Notices of the Royal Astronomical Society.

Scientists Susan Iglesias-Groth, from the Instituto de Astrofísica de Canarias (IAC) and Martina Marín-Dobrincic, from the Polytechnic University of Cartagena, have discovered the presence of numerous prebiotic molecules in the star-forming region IC348 of the Perseus Molecular Cloud, a group of stellar youth about 2-3 million years.

Some of these biological molecules are considered essential building blocks for the construction of more complex molecules such as amino acids, which formed the genetic code of ancient microorganisms and brought about the flourishing of life on Earth. Knowing the distribution and abundance of these precursor molecules in regions where planets are most likely forming is an important challenge for astrophysics.

The Perseus Cloud is one of the closest star-forming regions to the Solar System. Many of its stars are young and have protoplanetary disks where the physical processes that create planets can occur. “It is an extraordinary laboratory of organic chemistry”, explains Iglesias-Groth who in 2019 found fullerenes in the same cloud. These are complex molecules of pure carbon that often occur as building blocks for the main molecules of life.

Now new research has discovered in the interior of this region common molecules such as molecular hydrogen (H2), hydroxyl (OH), water (H2O), carbon dioxide (CO2) and ammonia (NH3) as well as some molecules containing carbon. which may 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).

The data also indicate 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 its molecular content,” says Iglesias-Gorth. “The novelty is that we see molecules in the diffuse gas from which stars and protoplanetary disks are forming.”

The presence of prebiotic molecules in interstellar sites so close to star clusters suggests the possibility that accretion processes are occurring on the young planets which may contribute to the formation of complex organic molecules. These key molecules could have been supplied to the newborn planets in the protoplanetary disks and thus could help create a pathway to the molecules of life,” Marina-Dobrincic points out.

The discovery by the two researchers is based on data obtained with NASA’s Spitzer satellite. The next step will be to use the powerful James Webb Space Telescope (JWST). The spectroscopic capability of JWST can provide details about the spatial distribution of all these molecules and extend the current search to others that are more complex, giving higher sensitivity and resolution which are essential to confirm the very likely presence of amino acids in the gas in this and other star-forming regions,” concludes Iglesias-Groth.

Reference: “A rich molecular chemistry in the gas of the star cluster IC 348 of the Perseus molecular cloud” by Susana Iglesias-Groth and Martina Marin-Dobrincic, March 16, 2023, Monthly Notices of the Royal Astronomical Society.
DOI: 10.1093/mnras/stad495