News from IBE (CSIC-UPF) and CEXS-UPF
Paula Jofré, of the University of Cambridge’s Institute of Astronomy, set about creating a phylogenetic “tree of life” that connects a number of stars in the galaxy. This paper is the result of a interdisciplinary collaboration with Jaume Bertranpetit of the IBE (CSIC-UPF), who spent a sabbatical year in Cambridge.
The team picked twenty-two stars, including the Sun, to study. The chemical elements have been carefully measured from data coming from ground-based high-resolution spectra taken with large telescopes located in the north of Chile. Once the families were identified using the chemical DNA, their evolution was studied with the help of their ages and kinematical properties obtained from the space mission Hipparcos. Two stars with the same chemical compositions are likely to have been born in the same molecular cloud. Some live longer than the age of the Universe and serve as fossil records of the composition of the gas at the time they were formed.
In evolution, organisms are linked together by a pattern of descent with modification as they evolve. Stars are very different from living organisms, but they still have a history of shared descent as they are formed from gas clouds, and carry that history in their chemical structure. By applying the same phylogenetic methods that biologists use to trace descent in plants and animals it is possible to explore the ‘evolution’ of stars in the Galaxy.
Paula Jofré et al. ‘Cosmic phylogeny: reconstructing the chemical history of the solar neighbourhood with an evolutionary tree’ is published by Monthly Notices of the Royal Astronomical Society. DOI 10.1093/mnras/stx075