The University of Tokyo
An artist's impression of the implied distribution of young stars, represented here by Cepheids shown as blue stars, plotted on the background of a drawing of the Milky Way.
The scientists found a desolate chunk of space surrounding the center of our galaxy that is devoid of young stars, which contradicts recent work done on the region.
The work was published in a paper in Monthly Notices of the Royal Astronomical Society.
A cosmic desert
The Milky Way, the beautiful spiral galaxy that we call home, contains billions of stars including our own star, the sun, about 26,000 light years from its center.
Scientists hope to understand how our galaxy formed and evolved by looking at how these stars are distributed. Pulsating, young stars called Cepheids are ideal for this. These stars, which are more than 4 billion years younger the the sun, regularly pulsate in brightness. The amount of time between pulses reveals the luminosity of the Cepheid, and astronomers can figure out how far the star is by comparing its brightness with what we see on Earth.
According to Noriyuki Matsunaga, who led the team, scientists had found Cepheids in the central heart of our Milky Way (in a region about 150 light years in radius) a while ago. "Now we [found] that outside this there is a huge Cepheid desert extending 8,000 light years from the center."
Sifting through the interstellar dust
The inner Milky Way is a tough place to spot these pulsating stars because it's packed with interstellar dust, which obscures these stars and their light.
To sift through this dust, the astronomers analyzed observations made with a telescope located in South Africa. They found a huge area stretching for thousands of light years from the Milky Way's core that had very few Cepheids.
"The current results indicate that there has been no significant star formation in this large region over hundreds of millions of years," co-author Giuseppe Bono said in the press release. "The movement and chemical composition of the new Cepheids are helping us to better understand the formation and evolution of the Milky Way."