Stellar heavy metals help astronomers trace history of galaxies

After recent research, astronomers have prepared a catalog of signs of nine heavy metals in the infrared light from supergiant and giant stars which can help them in tracing the history of galaxies.

Observing the catalog will help researchers in understanding how events like that of binary neutron star mergers affect the chemical composition as well as the evolution of Milky Way Galaxy and other galaxies.

After the big bang, the universe helium and hydrogen and other elements were formed later through nuclear fusion in stars o binary neutron star mergers or events supernovae.

Although the details of different processes and their contributions are poorly understood, it is necessary to better understand the chemical evolution of galaxies for understanding how the rich element environment of planets like Earth came to be.

Metals that are heavier than nickel can also be used to trace events like that of binary neutron star mergers.

A research team from the University of Tokyo looked for signs of heavy metals in 13 of giant and supergiant stars using the WINERED near-infrared spectrograph on the 1.3m Araki Telescope.

The large bright giant and supergiant stars are easy to observe in regions where interstellar matter blocks visible light.

Each of the elements that are present inside a star produces a distinct 'signature' in the light of the star by absorbing only specific wavelengths of the light.

Researchers compared the spectrum, the detailed information of wavelength of each of the star to libraries that contain dozens of theoretically predicted absorption lines and concluded that 23 of those lines that were produced by nine elements ranging from zinc to dysprosium could actually be observed.

According to these results, astronomers now can measure levels of such heavy metals present in other stars to map the chemical diversity as well as the evolution of all galaxies including our Milky Way.