A faint blue galaxy situated about 30 million light years from the Earth and located in the constellation “Leo Minor” can shed new light on birth of the universe.
Astronomers from Indiana University (IU) found that a galaxy nicknamed Leoncino or “little lion” contains the lowest level of heavy chemical elements or “metals” ever observed in a gravitationally bound system of stars.
“Finding the most metal-poor galaxy ever is exciting since it can help contribute to a quantitative test of the Big Bang,” said professor John J. Salzer from IU’s Bloomington College of Arts and Sciences.
There are relatively few ways to explore conditions at the birth of the universe, but low-metal galaxies are among the most promising.
This is because the current accepted model of the start of the universe makes clear predictions about the amount of helium and hydrogen present during the Big Bang.
The ratio of these atoms in metal-poor galaxies provides a direct test of the model.
To find these low-metal galaxies, however, astronomers must look far from home.
Our own Milky Way galaxy is a poor source of data due to the high level of heavier elements created over time by “stellar processing,” in which stars churn out heavier elements.
“Low metal abundance is essentially a sign that very little stellar activity has taken place compared to most galaxies,” added Alec S Hirschauer, graduate student in a paper appeared the Astrophysical Journal.
Leoncino is considered a member of the “local universe,” a region of space within about one billion light years from Earth and estimated to contain several million galaxies.
Aside from low levels of heavier elements, Leoncino is unique in several other ways.
A so-called “dwarf galaxy,” it’s only about 1,000 light years in diameter and composed of several million stars.
The Milky Way, by comparison, contains an estimated 200 billion to 400 billion stars.
“We’re eager to continue to explore this mysterious galaxy,” Salzer noted.