3:30–5:00 pm ERC 161
Title: Galactic Phylogenetics: reconstructing histories of stellar populations with methods from evolutionary biology.
Abstract: Chemical abundances of long-lived stars can be used to understand how the Milky Way formed and evolved. This is because such (fossil) stars retain in their atmosphere the chemical composition of the progenitor gas cloud, or Interstellar medium (ISM), which evolves. Its evolution is driven by the creation and pollution of new chemical elements from massive short-lived stars. Thus, stars that formed from the same parent evolving ISM at different times have different chemical abundance, and these chemical abundances increase with time. Connecting the chemical abundances of stars with the evolution of the Milky Way is in fact a standard evolutionary problem, and as such, can be addressed with phylogenetics.
Phylogenetics is the methodology created by biologists to reconstruct the evolutionary history of life forms on Earth. Indeed, more than a century ago, Darwin, without knowing about the existence of the DNA, realized that there was a mechanism transmitting information between one generation and the next. That transmission was called “descent with modification”: Every transmission implied a tiny modification of traits, but after a long time, these modifications accumulated and became significant. Phylogenetics aims to characterize the transmission mechanisms and reconstruct the past events that are responsible for the diversity of traits we observe today. Phylogenetics became an established method in evolutionary biology, and has revolutionized other fields such as archaeology and anthropology through the studies of culture, language or music evolution.
We have identified the process of “descent with modification” in galaxies: we know that the chemical elements of fossil stars contain the heritable information that is transmitted between stellar generations. In this talk I will invite you to think about Galactic phylogenetics and its prospects in evolutionary astrophysics. I will present and discuss the first steps we have made in this direction thanks to a Chilean collaboration project called Millennium Nucleus for the Evolutionary Reconstruction of the InterStellar medium (ERIS).
Zoom: https://uchicago.zoom.us/j/93092711418?pwd=ax8GAGcDkGPBQj9fe0P8I7TS1shSIl.1
