A vast expanse in the center of the Milky Way Galaxy may actually be a stellar desert completely devoid of young stars.
That is what an international team of astronomers concluded in a new study published in the Monthly Notices of the Royal Astronomical Society. The new report promises to revamp our understanding of the entire Milky Way.
Distribution Of Stars
Our galaxy is a spiral galaxy that contains many billions of stars, and our sun is just one of them.
Situated about 26,000 light-years away from the center, the sun and our entire solar system moves at an average velocity of 828,000 kilometers per hour around the center of the galaxy.
Measuring the distribution of stars in the Milky Way may be crucial in understanding how the galaxy began and formed, researchers believe.
Scientists say that Cepheids, or pulsating stars, are perfect for accomplishing this task. Compared to our sun, Cepheids are much younger — pulsating stars are 10 to 300 million years old, while the sun is 4.6 billion years old.
Cepheids are called pulsating stars for a reason: they pulsate or throb in brightness in a regular cycle.
The cycle's length is connected to the luminosity of the star, so if scientists monitor them, the precise brightness of the Cepheid can be established. Astronomers can then compare it with what can be seen from Earth and work out the distance.
However, although there are methods to study Cepheids, finding them in the inner Milky Way is not easy because the galaxy is filled with interstellar dust.
The interstellar dust often blocks out light and hides stars from view.
No New Stars?
Led by Noriyuki Matsunaga, researchers compensated for the difficulty by using a near-infrared Japanese-South African telescope at Sutherland.
To their surprise, scientists hardly found Cepheids or young stars in a huge region that stretched for thousands of light-years at the core of the Milky Way.
According to Matsunaga, they have previously discovered that Cepheids are in the central heart of our galaxy in a region about 150 light-years in radius.
Now, the study finds that a huge Cepheid desert extends out to 8,000 light-years from the galaxy's center.
Researchers say this can only mean that a large part of the Milky Way known as the Extreme Inner Disk contains no young stars.
Michael Feast, one of the co-authors of the study, says their findings contradict previous studies, but it does corroborate with the research of radio astronomers, which reveal no new stars being formed in the stellar desert.
