Building blocks for life found in clouds of dust forming planets

Astrophysicists who set out to map the building blocks of life in space have discovered precursor molecules hidden in clouds of dust destined to become future solar systems.

The discovery suggests that Earth may not be that special after all – many other worlds may have the same access to the life-forming compounds that we have.

“The key result of this work shows that the same ingredients necessary for the seeding of life on our planet are also found around other stars,” says University of Leeds astrochemist Catherine Walsh, who worked on research.

“It is possible that the molecules needed to start life on planets are readily available in all planet-forming environments. “

Despite all its splendid diversity, all life on Earth is built from the same recipe for mixing organic molecules and minerals in lukewarm water.

How this carbon-based chemistry soup took shape from a small handful of elements including hydrogen and nitrogen is a puzzle that has occupied researchers for more than a half. -century.

Recent findings suggest that Earth’s primordial biochemistry may have been triggered by processes among stars, and even beyond, making it all too tempting to predict that life should be common across the galaxy.

“However, many of the environments in which we find these complex organic molecules are quite distant from where and when we think planets form,” says John Ilee, astrophysicist at the University of Leeds in the UK, who led the research.

“We wanted to know more about the exact location and quantity of these molecules present in the birthplaces of planets – the protoplanetary disks.”

Ilee led a team of astrophysicists from around the world to map the location of a handful of leading biochemistry precursors in distant clouds of dust and rock that will eventually settle in everything new solar systems.

This is one of those “easier said than done” tasks of finding protoplanetary disks that are not only close enough to be scanned, but that are tilted so that the whole of their swirling material disc can be seen in all its glory.

Using the Atacama Large Millimeter / submillimeter Array (ALMA) in the Atacama Desert of northern Chile, Ilee and her team collected light from a number of protoplanetary disks looking for spectral signatures of various organic molecules.

In one study, researchers looked at the ratio of two important organic compounds, cyanide and hydrogen cyanide.

Ironically for such a toxic substance, hydrogen cyanide is considered a primary source of carbon and nitrogen in life-generating chemistry. Measuring its concentrations in the fog of matter surrounding a newborn star can help scientists get a better idea of ​​the interactions between the star’s radiation and the distribution of this potentially important ingredient.

Moving up the chain of complexity, the scientists also mapped the distributions of three larger molecules in five protoplanetary disks.

These compounds – cyanoacetylene (HC3N), acetonitrile (CH ??CN) and cyclopropenylidene (c-C3H2) – have already been found in our solar system, along with disks forming more distant planets.

The mapping of their densities and distributions allows us to state with certainty that the reservoirs of organic matter in the echo of emerging solar systems are more or less like those of ours.

The images at the bottom show the presence of each molecule in the protoplanetary disks. (J Ilee / University of Leeds)

The spectral fingerprints of these particular precursor molecules (above) suggest that they tend to be concentrated in the internal regions of the discs forming planets. In addition, their abundances are up to 100 times higher than predicted by current models.

In other words, this mixture of packets of organic dust that created life with just a little water on Earth isn’t that special.

Of course, it takes more than fertile soil for life to flourish. Some kind of fluid solvent, such as water, is useful. Just like the respite from the dazzling radiance blown by a nearby unleashed star.

But given the number of stars in our galaxy alone that could be home to planets with the benign conditions necessary to foster the evolution of chemistry, it’s heartwarming to know that their slime probably has all of the building blocks it needs to. have a good chance to start life.

This research has been accepted for publication in Astrophysical Journal Supplements Series, and is available for review on the arXiv.org preprint server.