Faint blue galaxy could possess Big Bang clues

BLOOMINGTON, Ind., May 12 (UPI) -- Researchers say a faint blue galaxy 30 million light-years away may offer insights into the birth of the universe.

The galaxy, discovered by astronomers at Indiana University, is small, faint and relatively unassuming. Its chemical contents, however, make it quite unusual. Researchers found surprisingly few heavy chemical elements inside the galaxy, which they dubbed Leoncino, or "little lion."

In fact, Leoncino boasts the fewest metals of any observed gravitationally bound star system.

"Finding the most metal-poor galaxy ever is exciting since it could help contribute to a quantitative test of the Big Bang," John J. Salzer, an astronomy professor at Indiana, said in a news release. "There are relatively few ways to explore conditions at the birth of the universe, but low-metal galaxies are among the most promising."

Most galaxies, especially those close to the Milky Way, feature relatively high levels of metals. Because heavy elements are forged inside the cores of burning stars, each generation of stars churns out more metals.

The Big Bang and early formation of the universe was completely devoid of heavy metals. Galaxies like Leoncino -- officially AGC 198691 -- feature conditions similar to the early universe, and offer astronomers a chance to test the models that simulate the Big Bang. Scientists are particularly keen on testing predictions about how much helium and hydrogen was present during the Big Bang.

Researchers use spectrography to measure the chemical contents of faraway star systems. Heavy metal ratios reveal a galaxy's star formation rate, and Leoncino is predictably on the slow end of the spectrum.

The little lion galaxy is relatively small. At just 1,000 light-years in diameter, it meets the definition of a dwarf galaxy. While the Milky Way contains as many as 400 billion stars, Leoncino hosts just a few million.

Its stars are relatively young and hot, but unusually dim -- Leoncino is the least luminous of its kind. These hot stars lend the galaxy a faint blue glow.

"We're eager to continue to explore this mysterious galaxy," said Salzer. "Low-metal-abundance galaxies are extremely rare, so we want to learn everything we can."

Researchers detailed their discovery of Leoncino in a paper published this week in the Astrophysical Journal.