The Milky Way Galaxy's Hidden Stars at Its Center May be Revealed with Radio Telescopes

Radio telescopes may be able to spot stars hidden in the galactic center of the Milky Way. Although the center of the Milky Way is a mysterious place, cloaked in dust, researchers believe that there may be a new way to clear the fog and spot stars in this region.

"There's a lot we don't know about the galactic center, and a lot we want to learn," said Idan Ginsburg, one of the researchers, in a news release. "Using this technique, we think we can find stars that no one has seen before."

There's a long way from the center of our galaxy to Earth. This path is choked with dust to the point that out of every trillion photons of visible light coming our way, only one photon will reach our telescopes. However, radio waves are from a different part of the electromagnetic spectrum. With their lower energies and longer wavelengths, it's possible for them to pass through the dust unimpeded.

On their own, though, stars at the galactic center aren't bright enough for these radio signals to reach us at such distances. However, if a star is traveling through gas faster than the speed of sound, the situation changes. Material blowing off the star as a stellar wind can blow into interstellar gases and create a shock wave. Through a process called synchrotron radiation, electrons accelerated by this wave produce radio emission that could potentially be detected.

With that said, the star would have to be moving at a speed of thousands of miles per second. This is potentially possible in the galactic center since the stars there are influenced by the strong gravity of a supermassive black hole.

Currently, the researchers suggest looking for this effect from one already known star, called S2. This star, which is hot and bright enough to be seen in the infrared despite the dust, will make its closest approach to the galactic center in late 2017, which makes it perfect for radio astronomers to target.

"S2 will be our litmus test," said Avi Loeb, co-author of the new study. "If it's seen in the radio, then potentially we can use this method to find smaller and fainter stars-stars that can't be seen any other way."

The findings are published in the journal Monthly Notices of the Royal Astronomical Society.

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