Indiana University astronomers have located a blue galaxy located about 30 million light years from Earth within the Leo Minor constellation that may be able to explain the beginnings of the universe. The galaxy has been called Leoncino, meaning little lion, and holds the lowest amount of metals ever seen in a gravitationally bound star system. The study was published this week in the Astrophysical Journal.
IU professor John J. Salzer, who was an author on the newest study says it was very exciting to find the galaxy with the least amount of metal because galaxies containing low amounts of metal are the most promising in finding more answers to the birth of the universe. These findings are part of the accepted model of the start of the universe, which predicts the amount of both helium and hydrogen at the time of the Big Bang. The ratio is directly related to those on galaxies with low metal content.
In order for astronomers to locate low-metal galaxies, they must search very far from planet Earth; even The Milky Way is not a very good source for such information because of stellar processing. Stars create heavier elements during nucleosynthesis. The atoms get sent back out into the galaxy upon exploding as supernovae. Alec S. Hirschauer, lead author on the paper and graduate student in the IU Bloomington College of Arts and Sciences’ Department of Astronomy says low metal levels are a sign of limited stellar activity.
Leoncino is part of the local universe, an area of space as far away as 1 billion light years from planet Earth. This part of the universe is thought to hold many million galaxies, while only a small fraction have been discovered. Leoncino is 29% lower in its metal prosperity compared to the last low-metal galaxy discovered back in 2005. Element documentation is done through spectroscopic observing; astronomers make their estimations based on the light emitted by galaxies, which appears like a rainbow. There are a wide range of bright lines, each indicating different gases, such as hydrogen, helium, or nitrogen. Atomic physics takes the light data and calculates the abundance of each type of element shown.
Salzer says a spectrum is worth a thousand pictures because of all the astonishing information that can be undiscovered from distances of millions of light years away. Leoncino is a dwarf galaxy because it is a mere 1,000 light years in diameter and made up of a few million stars. Many galaxies will carry anywhere from 200 or 400 billion stars. This unique dwarf galaxy is officially called AGC 198691 and is blue because of the presence of hot stars that were recently created. The stars display the lowest luminosity level that has ever been seen in systems of this kind.
Researchers are eager to continue to study the new galaxy. Salzer is hoping to get a chance to use the Hubble Space Telescope in order to get an even better glimpse of the latest findings. Since low-metal galaxies are very rare, he wants to learn as much as possible.