Helium hydrate was one of the first molecules that emerged in the universe during the first seconds after the Big Bang.
Now, scientists believe that ancient stars can help them better understand how the evolution of chemical elements in the universe has been.
The stars, which abound in space, are composed of 71% hydrogen and 27% helium, the first two chemical elements of the periodic table. In turn, the Earth and other planets concentrate heavier elements.
Hydrogen isotopes such as deuterium and tritium were the first to appear during the 100 seconds after the Big Bang.
Subsequently their atoms participated in the formation of the first stars. Scientists believe that at that time these celestial objects were very massive and a hundred times heavier than the Sun.
This fact caused a thermonuclear reaction that synthesized helium and small amounts of lithium and beryllium.
The first stars were so hot that they did not live for a long time and ended up exploding, becoming supernovae.
This was the most important stage in the evolution of the universe, as it enriched it with coal, oxygen, nitrogen and iron, among other metals.
After 1,000 million years, the number of stars decreased considerably. In these circumstances the formation of iron and other heavy elements should have been reduced. However, this scenario never took place.
Metals began to proliferate from type Ia supernovae that arose in a binary system composed of a white dwarf, Aleksandr Lutovinov of the Institute of Space Research of the Russian Academy of Sciences told Sputnik.
However, atoms that were heavier than iron needed more energy, and used to arise from the mechanism by which neutrons captured the atomic nucleus and caused beta decay to more stable forms, such as uranium and strontium.
Precisely this reaction was behind the synthesis of half of the stable atoms. Another half arose as a result of the slower reactions, the so-called process s and process r, which require the participation of neutrons with higher density.
Studies aimed at finding traces of chemical elements in space contributed to the emergence of a new branch in modern science: galactic archaeology.
The ancient stars that formed after the Big Bang in the confines of the galaxies approximately 13,000 million years ago are their main research subject.
Scientists believe that with their help they can take a look at the cradle of the universe and understand how the evolution of chemical elements began.
In 2015 astrophysicists discovered the dwarf galaxy Reticulum 2.
It is very small and weak, since it houses only several thousand stars. Seven of its nine brightest stars contain barium and europium synthesized there as a result of the implementation of the r processes.
Precisely this galaxy made scientists think that the fusion of two neutron stars was the first chemical laboratory in the universe.
The discoveries that would prove this hypothesis did not wait.
In August 2017, the Ligo and Vigo observatories detected the signal of a gravitational wave called GW170817 that had been generated following the merger of two neutron stars.
Subsequently, the Very Large Telescope Project of the European Southern Observatory (ESO), located in Chile, discovered a kilonova after studying the fusion site of these stars.
It is believed that this strong signal of electromagnetic radiation is the radioactive trace that is often left by the synthesis of heavy and unstable isotopes.
Although the scientists managed to detect the presence of heavy elements in the spectrum of this kilonova, they could not determine with certainty which ones it was.
Recently ESO researchers managed to identify the strontium that usually arises in large quantities during the first phase of fusion of neutron stars.
Source: Sputnik
