New clues about early star formation are putting a twinkle in astronomers’ eyes this week.
Researchers have discovered clouds of primordial gas from 2 billion years after the Big Bang that confirm what had only been theorized: that early star formations consisted only of the three lightest elements on the periodic table. The study is published in the journal Science.
A separate study published in Science suggests that early stars were much smaller than previously thought, contrary to earlier research that suggested the first stars were more massive than 100 suns. Takashi Hosokawa and colleagues found through numerical simulations that, in fact, the first stars were only about 43 times the mass of our sun.
Long before any star was light or bright, according to the modern cosmological theory, during the first few minutes after the Big Bang, three primary elements existed in the universe: hydrogen, helium and lithium.
The primordial gas is composed of the lightest elements in the periodic table and uncontaminated by the heavier periodic elements – termed “metals” – from stars.
Over the course of hundreds of millions of years after the Big Bang, clumps of primordial gas condensed to form the first stars.
For years, stargazing scientists have tried to find this “pristine” material but have failed – until now.
“It’s quite exciting, because it’s the first evidence that fully matches the composition of the primordial gas predicted by the Big Bang theory,” lead author Michele Fumagalli said in a statement.
Fumagalli, a graduate student at University of California, Santa Cruz, and colleagues found the two new pristine clouds while studying the gas properties of galaxies in the distant universe.
Using the spectrometer on one of the world’s more powerful optical telescopes – the Keck I Telescope in Hawaii – astronomers analyzed the wavelengths and mapped out the gas distribution of these distant galaxies.
“We can see absorption lines in the spectrum where the light was absorbed by the gas and that allows us to measure the composition of the gas,” Fumagalli said in a statement.
The researchers are working to understand how common these primordial clouds are and how metals got released in the early galaxies, Fumagalli said.
For more information, check out the Science podcast interview with Fumagalli.