Astronomers probing the innermost region of the Milky Way galaxy have found a stellar desert, around 16,000 light-years across, where no new stars have been born for hundreds of millions of years.
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The findings are published today in the journal Monthly Notices of the Royal Astronomical Society.
Measuring the distribution of stars in the Milky Way may be crucial in understanding how the galaxy began and formed, researchers believe.
This stellar dessert has puzzled astronomers, who found the desolate region of Milky Way when they were peering into the heart of the galaxy. According to the astronomers, the empty heart of the galaxy is a hard-to-explain mystery because it is not easy to see what’s happening inside the galaxy because we are immersed in it, they added.
In addition, this discovery suggests that a sizable portion of the Milky Way, known as the Extreme Inner Disk, hosts no young stars.
Though you don’t hear about them often, Cepheids are important to astronomers who are trying to understand how stars are distributed throughout the Universe, because they’re young – sometimes just 10 million-years-old – and pulse bright enough that researchers can use their light to calculate how far away they are.
Accordingly, in order to take a closer look at the goings-on in the centre of the Galaxy, Matsunaga and team used the Infrared Survey Facility (IRSF) 1.4-m telescope and the SIRIUS IR camera located at Sutherland, South Africa, to make their observations.
That means there’s a huge swath of the Milky Way that isn’t producing new stars. Our sun – which sits roughly 26,000 light years from the middle of the galaxy – moves at an average velocity of 828,000 kilometers per hour around its center. “Now we find that outside this there is a huge Cepheid desert extending out to 8,000 light years from the centre”.
Co-author Giuseppe Bono says: “The current results indicate that there has been no significant star formation in this large region over hundreds of millions years”.
There lies an abundance of older stars and less younger stars at the center of the Milky Way, but a new study has found that there are even less juvenile stars than previously thought.
Other studies, some dating back decades, have supported the idea of limited star formation in the galaxy’s inner disk. They are much younger than our Sun and they pulsate in brightness in a regular cycle. With the exception of a small clump in the galactic centre, the central 8,000 light-years appear to have very few pulsating stars – and hence, very few young stars.
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.
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Astronomers from Japan, South-Africa and Italy teamed up for a study, in which they were studying the evolution of our galaxy by observing the stars, which was led by Noriyuki Matsunaga from the University of Tokyo.
