Stellar desert in the middle of Milky Way puzzles scientists

© David Gray
An international team of astronomers has found hardly any young stars, Cepheids, in the innermost part of our galaxy, suggesting contrary to previous researches that there is a giant "desert" in the center of the Milky Way.

Aiming to better understand processes within our galaxy and formations of new space bodies, scientists from several countries, led by Japan, have been looking at a particular type of stars called Cepheids. Ranging from between 10 and 300 million years old, these "pulsating supergiants" are considered to be young stars themselves, and "useful tracers of young stellar populations."

Pulsating at a certain rate related to their brightness, Cepheids allow astronomers to estimate their distances from us. Although sometimes they're not so easy to spot far away in the galaxy, when obscured by interstellar dust, the team of astronomers have this time used the Infrared Survey Facility (IRSF) 1.4-m telescope in South Africa, which allowed them to see through the dust clouds.

While it was believed that new stars were born deep in the center of our galaxy, having conducted observations for several years, between 2007 and 2012, the astronomers have found no young stellar formations close to that area.

"[T]here is a huge Cepheid desert extending out to 8000 light years from the center," said Noriyuki Matsunaga, one of the authors behind the study, which was published in the Monthly Notices of the Royal Astronomical Society this week. The Sun, one of the billions of stars in the Milky Way, is some 26,000 light years from the center of our galaxy.

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"Our conclusions are contrary to other recent work, but in line with the work of radio astronomers who see no new stars being born in this desert," said co-author of the research, Giuseppe Bono, as cited by Phys.Org.

Saying that there "has been no significant star formation" in this large stellar "desert" for over hundreds of millions years, astronomers are surprised with the newly-discovered Cepheids void, and are yet to find out why no new stars are being born in the large area of space.