The sky is made of the elements helium, carbon dioxide, and hydrogen.
The gas that surrounds stars is the stuff that we see.
But what’s in those gas clouds?
There’s an abundance of helium in the universe, but it’s rare and very dense.
And that’s where the stars shine.
“We think that most of that helium is concentrated in a small fraction of the starlight,” said Michael DeSantis, a professor of astronomy at the University of Arizona.
The amount of helium is determined by the density of the gas, the distance from the star, and how much gas the star emits.
So what DeSants team found is that stars in the early universe, before there was a Big Bang, emitted helium gas that was 10 times denser than the gas in the clouds surrounding them.
That’s why the sky is so bright and the stars so bright.
“But the helium is also the main ingredient of the helium-3 stars,” DeSantes said.
So we know that helium-4 stars also have a high concentration of helium gas.
This isn’t just a matter of gas and stars, though.
The atmosphere of stars in our Milky Way is dominated by hydrogen atoms and helium.
That means the hydrogen atoms have a higher affinity for helium than the helium atoms that make up most of the rest of the galaxy.
That explains why stars with the highest concentrations of helium are usually the ones we see with the greatest amount of light.
DeSantas team found the stars that emitted the most helium were some of the most massive and were the most common.
“If you look at the brightest stars in this region, they’re about as massive as the sun,” De Santis said.
That could mean that these stars are more likely to be stars in their core, the outermost region of the Milky Way.
The helium-rich clouds surrounding these stars may also make them easier to observe.
“A number of stars have a similar structure to helium-1 stars, where helium is the main element,” De Santis said.
“So the star may have an abundance [of helium], but it may also have an abundant [of hydrogen],” he added.
Stars with higher helium abundances are easier to see with telescopes, and De Sants team has seen them on many different types of telescopes, including the Very Large Telescope, the Very Long Baseline Array, the Wide Field Camera 3, and the Advanced Telescope Array.
De Santa is planning a follow-up project in the future to study the stars in greater detail.
But until then, DeSante says that we’re likely to see more and more stars with helium-heavy clouds, including in the Milky Road.