New stars can, in fact, form very close to the Milky Way's central black hole, according to a recent study published by the Harvard-Smithsonian Center for Astrophysics.
The center of the Milky Way is wracked with powerful gravitational tides stirred by a gigantic black hole. Those tides should rip apart molecular clouds that act as stellar nurseries, preventing stars from forming in place. Yet the alternative -- stars falling inward after forming elsewhere -- should be rare occurrences.
Using the Very Large Array of radio telescopes, astronomers from the Harvard-Smithsonian Center for Astrophysics in the United States and the Max Planck Institute for Radio Astronomy in Germany have identified two proto-stars located only a few light years from the galactic center.
"We literally caught these stars in the act of forming," said Smithsonian astronomer Elizabeth Humphreys, who presented the finding Monday at a meeting of the American Astronomical Society in Long Beach, California.
The center of the Milky Way is a mysterious region hidden behind intervening dust and gas, making it hard to study. Visible light does not make it out, leaving astronomers no choice but to use other wavelengths such as infrared and radio, which can penetrate dust more easily.
Humphreys and her colleagues searched for water masers - radio signals that serve as signposts for proto-stars still embedded in their birth cocoons. They found two proto-stars located seven and 10 light years from the galactic center.
Combined with one previously identified proto-star, the three examples show that star formation is taking place near the Milky Way's core.
Their finding suggests that molecular gas at the center of our galaxy must be denser than previously believed.
A higher density would make it easier for a molecular cloud's self-gravity to overcome tides from the black hole, allowing it to not only hold together but also collapse and form new stars.
The discovery of these proto-stars corroborates recent theoretical work, in which a supercomputer simulation produced star formation within a few light years of the Milky Way's central black hole.
"We don't understand the environment at the galactic center very well yet," Humphreys said.
"By combining observational studies like ours with theoretical work, we hope to get a better handle on what's happening at our galaxy's core. Then, we can extrapolate to more distant galaxies," she said.
Source:Xinhua
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