Astronomers at the University of Arizona, funded by two grants from the US National Science Foundation, have developed a theory to explain the presence of the most important molecules in the interstellar gas. why.
Evidence suggests that carbon nanotubes can arise from the dust and gas around dying stars. Image credit: NASA and the Hubble Heritage Team (STScI/AURA)
The team simulated the environment of dying stars and observed the formation of buckyballs (carbon atoms bonded to three other carbons by covalent bonds) and carbon nanotubes (roll up single-layer sheets of carbon atoms). The findings indicate that buckyballs and carbon nanotubes can form when silicon carbide dust – known to be close to dying stars – releases carbon in response to high temperatures, shock waves and energetic particles high.
“We know from infrared observations that buckyballs inhabit the interstellar medium,” said Jacob Bernal, who led the study. “The big deal is explaining how these giant, complex carbon molecules can form in an environment saturated with hydrogen, which is what you usually get around a dying star.”
Structural rearrangements of graphene (a single-layer sheet of carbon atoms) can create buckyballs and nanotubes. Based on that, the team heated samples of silicon carbide to a temperature that could mimic the halo of a dying star and observed the formation of nanotubes.
“We were amazed that we were able to create these extraordinary structures,” says Bernal. “Chemically, our nanotubes are simple but incredibly beautiful.”
Buckyballs are the largest molecules currently known to occur in interstellar space. It is now known that buckthorn spheres containing 60 to 70 carbon atoms are common.
“We know the raw material is there, and we know the conditions are very close to what you see near the shell of a dying star.” research co-author Lucy Ziurys said. “Shock waves pass through the envelope, and temperature and pressure conditions have been shown to exist in space. We also see buckyballs in planetary nebulae – in other words, we see the beginning and end products you would expect in our experiments. “
Source: NSF
