The Milky Way has a giant void of young stars

A team of Japanese, South African, and Italian astronomers recently found that there is a massive region around the center of the Milky Way that is devoid of young stars. 

The Milky Way is a spiral galaxy, and the Sun is almost 26,000 light-years from the center in one of its spiral arms. Measuring the distribution of stars within the galaxy is very important in understanding how our galaxy formed and evolved.

Young, pulsating stars called Cepheid Variable stars, or Cepheids for short, are the perfect candidate for this. They are between 10 and 300 million years old, younger than our Sun at 4.6 billion years old, and pulsate in their brightness in a repeating cycle. As this pulsation time is related to its luminosity, astronomers can monitor them to determine their actual brightness; after comparing this with the brightness as seen from Earth, a distance can be determined.

Finding these stars is difficult as the center of the galaxy is full of interstellar dust that obscures the light and hides many stars from view. Using near-infrared observations from the South African Large Telescope (SALT), the team was able to see past the dust; to their surprise they found hardly and Cepheids around a region about 1,000 light-years wide from the core of the galaxy.

The recent findings suggest that the extreme inner disk has virtually no young stars and that no significant amount of star formation has occurred in this area for hundreds of millions of years. The chemical makeup and movement of the Cepheid Variable stars are guiding the team in understanding the formation of the galaxy.

Mostly Cepheids have been used to measure distances of objects in far off in the universe, but this new study shows that the same technique can be used in revealing information a lot closer to home.

To know more about the research, click here.