The Galactic Family Tree: How Star Chemistry Tells the Story ⚡ экспресс
Phylogenetic methods from biology have been adapted to reconstruct the chemical evolution of stars in a disk galaxy model. In a high-resolution simulation, the history of chemical enrichment from different stellar sources was tracked, and phylogenetic trees were built for two regions: an inner ring that experienced inflows along the bar, and an outer ring shaped by spiral arms. Tree balance was assessed using the corrected Colless index. The inner-ring tree highlights a compact clade of old stars enriched by Type II supernovae, followed by a hierarchical structure with increasing contributions from Type Ia supernovae and asymptotic giant branch stars. The outer ring is represented by symmetrical, “caterpillar” trees with smooth gradients—a sign of prolonged star formation and mixing. Chemical enrichment rates confirm: fast in the center, gradual in the periphery. Structural indices differ significantly and converge with samples as small as 100 stars. Galactic phylogenetics serves as a new tool for reading the fossil record of galaxies.
A star inherits the chemical makeup of its parent gas cloud—just like a child inherits genes from its parents. Astronomers turned this into a method: by measuring the fraction of carbon and other elements with spectroscopy (splitting light into colors), they construct family trees for the stars in a galaxy. It’s like genealogy, but instead of DNA, you’re tracing chemistry.
In the center of the Milky Way, gas poured in stormy streams, stars were born rapidly, and enriched by supernova explosions. Their tree is a tangled bush with short, thick branches. On the outskirts, shaped by spiral arms, the process was smooth: the tree grew with thin, long, symmetrical branches.
This chemical pedigree acts as a time machine for galaxies. By studying these “fossils,” we read the history of bursts and stellar winds, reconstructing the growth of our own Galaxy.
🎯 Some of the Milky Way’s oldest stars contain almost no heavy elements, as if frozen in the era of the early Universe.