The Stellar Guide


How Elements are Discovered in Stars

As an electron moves to a lower energy level, it puts electromagnetic radiation at a certain wavelength. Each element has a different set of these, so you can tell which element emitted the radiation by looking at the bright line spectra. Similarly, you can tell which elements exist in a star by looking at the bright line spectrum of the star, and comparing the result to spectra of certain elements we know.

Elements in The Sun

Why this is Helpful for Astronomers

Spectroscopy tells us the age of a star by looking at the amount of its matter made up of chemical elements other than hydrogen and helium.

"The earliest stars were composed of just hydrogen and helium because they were the first elements to form after the Big Bang".

As these first stars reached the end of their lives and ran out of hydrogen fuel to fuse into helium, they began fusing helium into heavier and heavier elements, eventually producing iron.

Because stars can't fuse iron into anything heavier, gravity takes over, collapsing the star and causing a supernova explosion, seeding the universe in heavier elements from which the next generation of stars are born.

Knowing the age helps astronomers to find planets. The stars that are older mean the planets around them are older which means life could of formed.