Galaxies in space can feed off each other’s waste, creating new stars. Astronomers have found evidence that a huge galaxy inside an even larger nebula called MAMMOTH-1 is absorbing material from its surroundings to produce new stars. It is a kind of “recycling plant” in space.
Stars get their energy from nuclear fusion by converting hydrogen atoms into helium. Only massive stars become supernovae after all their hydrogen is converted into helium. Gravity then causes the massive star to collapse, which soon explodes in an extremely bright explosion that blows away its outer layers. Supernovae cause shock waves, which can generate enough energy to create new atomic nuclei – even the nuclei of heavy elements such as iron.
The remains of dead stars scatter into space, swirling into the interstellar medium. Some of this material is lost to space, but stars can still potentially include some of the material created in a supernova explosion.
The MAMMOTH-1 nebula contains the raw material for star formation, and observations have shown that three gas streams flow out of the nebula into one of the galaxies within it. The gas streams extend an astounding 100 kiloparsecs (325,000 light-years) from the galaxy that absorbs them. These streams could provide the galaxy with the raw material for new stars.
The research team created kinematic models to see exactly how the gas streams moved. The streams appear to be spiraling inward into the galaxy, further evidence of the vast amount of material that could be recycled into new stars.
Observations showed that these streams glowed with emission lines that indicated the presence of hydrogen and helium, which was to be expected. But there was also a significant amount of carbon. The presence of carbon shows that the cloud contains heavier elements that probably came from stars that died long ago.
Also, the MAMMOTH-1 observations revealed that the two gas streams heading toward the galaxy came from the same quasar. Quasars develop when supermassive black holes at the center of galaxies absorb enough material to emit jets of matter and extreme radiation. These jets can completely eject material from the galaxy.
Researchers have determined that this quasar is most likely located in the wrong galaxy to absorb material. Thus, this appears to be a case where one galaxy recycles material ejected from another.
This discovery allows scientists to better understand star formation and the evolution of galaxies in space. They can use this data to create more accurate models that will help them better understand how stars and galaxies form and evolve.