Recently, one of our subscribers asked me the following question:
How are different elements formed from hydrogen to heavy metals through stars?
Soon after the Universe appeared, the first atomic nuclei were formed, resulting in the Universe being filled with 90% hydrogen nuclei (protons) and 10% helium nuclei. Besides them, there was also a tiny amount of lithium, which did not exceed 0.00001% of all nuclei, while the content of heavier nuclei was even thousands of times less. However, we now have a huge amount of heavy elements in the composition of planets and gas-dust nebulae, and the source of all these substances is stars.
All heavy chemical elements are formed through stars, but the mechanism is different for different chemical elements.
From Helium to Iron
If you look at the periodic table, all elements, from helium to iron, are formed similarly. After the birth of any star, nuclear fusion reactions occur within it due to high temperature and pressure, in which hydrogen is converted into helium. There are several mechanisms for this combination, but as a result of each of them, four hydrogen nuclei turn into a helium-4 nucleus. The mechanism most often encountered is shown below in the picture.
