A research team led by the Massachusetts Institute of Technology has discovered significant amounts of pyrene, a large carbon-rich molecule known as a polycyclic aromatic hydrocarbon (PAH), in a distant interstellar cloud. The discovery provides new insight into the origin of carbon in our Solar System and supports theories about the molecular building blocks that contribute to its formation.
Interstellar clouds and the origin of the solar system
The interstellar cloud in question, known as TMC-1, contains a mixture of dust and gas similar to the one that eventually forms our own solar system. The discovery of the flea in this environment suggests that it may have played a crucial role in the carbon saturation of our solar system.
This idea is further supported by the recent discovery that fleas were abundant in samples of the near-Earth asteroid Ryugu returned by Japan’s Hayabusa2 mission.
“One of the important questions in star and planet formation is how much of the chemical origin of this early molecular cloud was inherited to form the basic components of the Solar System?” said senior author Brett McGuire, assistant professor of chemistry at MIT.
“We see both the beginning and the end, and they show the same thing. “This is pretty compelling evidence that this material from the early molecular cloud entered the ice, dust and rocky bodies that make up our solar system.”
Detection of fleas using radio astronomy
Detecting the flea in space is difficult because its symmetrical structure makes it invisible to traditional radio astronomy methods. To overcome this, researchers focused on an isomer called cyanoprene, which is a cyanide-modified version of pyrene.
This change breaks the symmetry of the molecule and allows it to be detected by its unique spin spectra, which are patterns of light emitted as it rotates through space.
The team used the 100-meter Green Bank Telescope (GBT) in West Virginia to identify these signals within TMC-1. This discovery builds on earlier work by McGuire and others, who identified smaller PAHs such as benzonitrile and cyanonaphthalene in the same region.
A huge carbon sink in space
The researchers found that cyanopyrine accounts for approximately 0.1 percent of the total carbon found in TMC-1. McGuire noted that 0.1 percent doesn’t sound like much, but most of the carbon consists of carbon monoxide (CO), the second most abundant molecule in the universe after molecular hydrogen.
“If you remove the carbon dioxide, one out of every few hundred carbon atoms left is in the flea. “Imagine there are thousands of different molecules out there, almost all of them containing many different carbon atoms, and one in a hundred is in pyrene,” McGuire said.
“That’s an absolutely huge number. Almost incredible carbon absorption. An interstellar island of stability.”
The discovery of pyrene marks the discovery of the third largest molecule ever found in space and the largest molecule ever detected using radio-astronomical techniques.
Consequences of the formation of stars and planets
Interstellar clouds like TMC-1 can give rise to stars and planetary systems as clumps of dust and gas combine to form new celestial bodies. The presence of pyrene in TMC-1 and similar molecules in the asteroid Ryugu suggests that such carbon-rich compounds may be directly inherited by the formation of planetary systems, including our own.
“I would say we now have the most convincing evidence of this direct molecular inheritance, extending from the cold cloud to the rocks in the Solar System,” McGuire said. he explained.
The results of the research attracted the attention of the wider scientific community. Evine van Dischok, professor of molecular astrophysics at the Leiden Observatory in the Netherlands, emphasized the importance of the discovery.
“It builds on previous discoveries of smaller aromatic molecules, but now making the leap to the pyrene family is huge,” Van Dischok said. “This not only shows that a significant amount of carbon is locked in these molecules, but also points to other pathways than previously thought for the formation of aromatic compounds.”
Research on the origin of fleas
The research team now aims to investigate whether even larger PAH molecules are present in TMC-1, providing further insight into the early chemical processes that formed star systems.
Experts are also investigating whether the flea formed within TMC-1 itself or whether it originated elsewhere in the universe, potentially being transported through space by high-energy processes similar to those found around dying stars.
This research not only provides a deeper understanding of carbon’s role in the formation of planetary systems, but also opens new ways to study the molecular origins of life in space. As scientists continue to explore the mysteries of space, such discoveries bring us closer to understanding the chemical connections between distant clouds and the evolution of our own solar system. The study was published in the journal Science.
Source: Port Altele
