Milky Way Galaxy Gobbles Gas 'Pills' for Star Formation

The Milky Way Galaxy has been making stars for the last eight billion years--an impressive feat by any stretch of the imagination. But how has the Galaxy managed to keep producing stars for all of this time? Astronomers have long wondered what mechanism is responsible and now, they may have their answer.

When old stars die, some of their gas goes back into the galactic "soup" for star making. But most of this gas is locked up in long-lived dwarf stars. This means that the Galaxy needs to procure fresh supplies of gas for birthing stars from some other location. While some astronomers believe that gas rains in from intergalactic space in the form of clouds, there's an issue with this particular theory. If a regular gas cloud were to hit the warm outer parts of the Galaxy, the halo, the gas would dissipate and would never reach the Galaxy's starry disk where star formation occurs.

In order to find out a little bit more about what might contribute to star formation, the researchers examined a gas cloud falling into the Galaxy called the Smith Cloud. Named after the woman who discovered it, this cloud possesses a weak magnetic field that's about .002 percent of the strength of Earth's. This cloud is one of the thousands of high-velocity clouds of hydrogen gas that fly around the outskirts of our Galaxy.

Although the magnetic cloud is weak, though, it could hold the explanation as to how gas clouds manage to keep together. Like a coated aspirin tablet that goes through your stomach undigested and then releases its contents when it hits your intestine, this gas cloud is coated by its weak magnetic field until it reaches the appropriate place in the Galaxy.

The findings reveal a little bit more about star formation and shows how gas clouds contribute. More specifically, the research shows that Smith's Cloud may just be part of this particular phenomenon as it falls into the Galaxy.

The findings are published in The Astrophysical Journal.