The Elements of Life Mapped Across the Milky Way

The Sloan Digital Sky Survey have mapped the elements of life across the Milky Way

‘For the first time, we can now study the distribution of elements across our Galaxy,’ says Sten Hasselquist of New Mexico State University. ‘The elements we measure include the atoms that make up 97% of the mass of the human body.’

The new results come from a catalog of more than 150,000 stars; for each star, it includes the amount of each of almost two dozen chemical elements. The new catalog includes all of the so-called ‘CHNOPS elements’ – carbon, hydrogen, nitrogen, oxygen, phosphorous, and sulfur – known to be the building blocks of all life on Earth. This is the first time that measurements of all of the CHNOPS elements have been made for such a large number of stars.

While humans are 65% oxygen by mass, oxygen makes up less than 1% of the mass of all of elements in space. Stars are mostly hydrogen, but small amounts of heavier elements such as oxygen can be detected in the spectra of stars. With these new results, APOGEE has found more of these heavier elements in the inner Galaxy. Stars in the inner galaxy are also older, so this means more of the elements of life were synthesized earlier in the inner parts of the Galaxy than in the outer parts.

While it’s fun speculate what impact the inner Galaxy’s composition might have on where life pops up, we are much better at understanding the formation of stars in our Galaxy. Because the processes producing each element occur in specific types of stars and proceed at different rates, they leave specific signatures in the chemical abundance patterns measured by SDSS/APOGEE. This means that SDSS/APOGEE’s new elemental abundance catalog provides data to compare with the predictions made by models of galaxy formation.

Also they’ve updated Origin of the Elements in the Solar System.