An article published in the journal “Monthly Notices of the Royal Astronomical Society” reports a study on the importance of the ejection of materials by stars in the last stages of their life in the formation of life forms such as those on the Earth. Professor Michael Smith and PhD student Igor Novikov of the British University of Kent performed a series of computer simulations of processes in protoplanetary nebulae obtaining results that offer important clues concerning the recycling of materials generated in stars and ejected into interstellar space.

Since scientists discovered how stars work, it’s known that elements heavier than those originally present are created especially during nuclear fusion and, in the case of massive stars, during the supernova phase. However, most stars have insufficient mass to explode so it wasn’t clear what happened to the materials produced by nuclear fusion. Michael Smith and Igor Novikov of the University of Kent’s Center for Astrophysics and Planetary Science tried to solve this mystery by mapping the evolution of starlight in different environmental conditions using 2D models. Put simply, they simulated the formation of a protoplanetary nebula, a phase of the dying star’s agony.

The results of the simulations show that there’s a shell of materials that is ejected while a star is aging. The gas and energy expelled during this process end up in interstellar space and, through a fragmentation process, are recycled into new stars and planets. In particular, the researchers focused on the shells of dying red giants.

According to the researchers, red giant shells must be temporary so that the processes that lead to the diffusion of the elements that allow the formation of life can happen. Shells are not uniform but may have variable characteristics. Most are likely cold and molecular and get fragmented. On the contrary, warm, atomic shells are stable.

The peak of recycling of the materials produced by stars may have allowed the formation of life on Earth. It’s an interesting idea that brings together the study of the processes that take place during the last phases of stars life with that of the conditions of life formation. The connection between such different events can offer new information to better understand the birth of life and consequently to the search for life forms in other places of the universe.