The first stars to blaze up in the Milky Way burned out long ago and gave birth to the next generations. However, the set of chemical elements that they scattered across the Galaxy allows even their "past lives" to be studied.
The earliest universe was filled with hydrogen with only small amounts of helium. All other naturally occurring chemical elements (astronomers simply call them "metals") appeared during the merger of these light nuclei in the depths of previous generations of stars and in supernova explosions. The matter scattered across space was part of the next generations, the metallicity of which was already higher, and here it again underwent transformation …
These "chemical traces", preserved in the stars, allow us to study their predecessors. This work was done recently by the American astronomer Ian Roederer and his colleagues, who published their results in the Astrophysical Journal Letters. Using the spectrograph of the Hubble Space Telescope, scientists studied the composition of BD + 44 493. Located 600 light years from Earth, it remains one of the brightest second-generation stars in the entire Milky Way, visible simply with good binoculars.
BD + 44 493 is interesting not only for this. Previous work has shown that its composition is relatively high in carbon, but the content of iron and other heavy elements is reduced. Such a picture suggests that BD + 44 493 most likely appeared "directly" from the remains of one star of the previous generation. After examining it, scientists discovered sulfur, phosphorus, and zinc in BD + 44 493. The number and composition of these three elements may indicate that the star in which they formed was quite massive - perhaps more than 20 times the mass of the Sun - and died in a supernova explosion.