Star is born: A study reveals complex chemistry in'stellar nurseries.
The journey of the universe's carbon-atoms is long. They begin in dying stars and then become part of planets and living organisms. A team has now discovered the chemistry behind a tiny but crucial step in this pro.
A team of international researchers discovered a crucial step in the chemical evolution and formation of molecules in cosmic "stellar nurseryries." Over millions of years, trillions upon trillions of molecules are swirling in these huge clouds of cold gas or dust in space. These interstellar clouds eventually collapse, resulting in the birth of young stars and planets.
Stargazer nurseries, like human bodies, contain many organic molecules. These molecules are mostly made up of carbon and hydrogen atoms. The results of the group, published in Nature Astronomy on Feb. 6, reveal how large organic molecules can form within these clouds. This is just one small step in the long chemical journey carbon atoms go through. They first form in the hearts of dying stars and then become part of planets and living organisms on Earth." In these cold molecular cloud, you're creating first building blocks that will eventually form stars and planets," said Jordy Bouwman (research associate at the Laboratory for Atmospheric and Space Physics, LASP) and assistant professor in Chemistry at the University of Colorado Boulder.Bouwman and his coworkers took a deep dive into a particular stellar nursery for the new study: the Taurus Molecular Cloud. This region is located in the constellation Taurus, and is approximately 440 lightyears (more than 2 quadrillion mile) from Earth. This complex, chemically-rich environment is an example what astronomers refer to as an "accreting core" or "accreting starless center".Although the cloud has begun to fall, scientists have yet to detect embryonic stars emerging within it.
The team's findings are based on a simple molecule called orthobenzyne. The researchers used computer simulations and experiments on Earth to show that this molecule can easily combine with other molecules in space to create a wide variety of larger organic molecules.
He said, "We're only at a beginning of understanding how we go between these small building blocks and larger molecules. I believe we'll discover that this chemistry will be so much more complicated than we thought, even in the earliest stages star formation." He said that cold molecular clouds may not appear to be a hotbed for chemical activity on the surface. These galactic primordial soups are, as their name suggests, frigid. They can reach temperatures of around -263 Celsius (or -440 Fahrenheit), which is only 10 degrees above absolute zero. Most reactions require heat to kick-start.
Complex chemistry seems to be occurring in stellar nurseries, cold or hot. They are known as "five-membered rings compounds" by chemists because each contains a ring of carbon molecules shaped like a pentagon.
Researchers using the Yebes 40-metre Radiotelescope (Spanish) discovered an unexpected molecule in the clouds of TMC-1 gas in 2021. It was ortho-benzyne. Bouwman explained that this small, extrovert molecule is made up of a six-carbon atom-rich ring with four hydrogens. It can interact with many other molecules without requiring a lot heat and is easy to interact with.
Bouwman and his colleagues, who hail from the United States of America, Germany, the Netherlands, and Switzerland, used a technique called "photoelectron coincidence spectroscopy" to discover the complex chemistry occurring in TMC-1.
To identify chemical reactions, the team used light from a huge facility called a synchrotron source. They discovered that ortho-benzyne, another common component of molecular clouds was easily combined to form larger and more complex organic compound.
The team then used computer models to study the role of orthobenzyne in a stellar nursey spread over several light-years deep in space. The results were promising: The models produced clouds of gas that contained roughly the same mixture of organic molecules as what astronomers had seen in TMC-1 with telescopes.
He said that scientists still have much to learn about all the reactions occurring in TMC-1.
He would like to study, for instance, how organic molecules in space pick up nitrogen atoms -- essential components of DNA and amino acids of living creatures on Earth.
Researchers from Leiden University, Benedictine College, the University of Wurzburg, Germany, and the Paul Scherrer Institute, Switzerland are co-authors of the new paper.