Around the globe, recycling signs are everywhere, urging us to save the planet while we can. In space, some galaxies apparently circulate without any reminder of it.
At least one galaxy hasn’t wasted any potential star-forming material. An international team of scientists led by astronomers Shiwu Zhang and Zheng Cai of China’s Tsinghua University has found evidence that a massive galaxy within an even larger nebula called Mammoth 1 is pulling in material from its surroundings to form new stars. bottom.
However, the material contains elements formed by past supernovae that are thought to have occurred within the galaxy, and the elements formed by the supernovae were blown into the nebula by the black hole at the center of the galaxy. This means that the galaxy, which the researchers call G-2, is forming stars from material that was previously blasted into intergalactic space by itself or by another nearby galaxy.
“Simulations show that gas recycling, the re-accretion of gas previously ejected from galaxies, could sustain star formation in the early universe,” the researchers recently published. said in the study. chemistry.
Recycled, great style
Stars use the energy from nuclear fusion as fuel to break hydrogen atoms into helium. Only massive stars (greater than 8 solar masses) become supernovae after merging all the hydrogen into helium. Gravity then causes the massive star to collapse, immediately producing a very bright explosion that blows away the outer layers. Supernovae cause shock waves that can generate enough power to fuse new atomic nuclei and even metals such as iron.
However, the death of one star can mean the birth of another. After the explosion, the dead star’s remnants scatter into space, swirling in the interstellar medium. Some of this material is lost to space forever, but stars may still take in some of the supernova-produced material.
The heavy elements produced by supernovae act as tracking devices when stars take in the remnants of previous generations of stars. Newly formed stars are always mostly hydrogen and helium, but the extent to which the heavier elements are present tells us something about the history of the materials used to create them.
don’t cross the stream
The Mammoth 1 Nebula is rich in raw material for star formation, and observations from the Subaru and Keck II telescopes have revealed three gas streams flowing from the nebula into one of its inner galaxies. Mammoth 1 is a particularly large nebula worthy of its name. Streams of gas from this nebula extend to a staggering distance of 100 kiloparsecs (325,000 light-years) from the galaxy encasing them. These currents could supply the galaxy with something to inform new generations of stars.
To see exactly how the gas stream moves, the research team created a kinetic model showing the motion of objects in both galaxies and nebulae. The flow appears to spiral inward toward the galaxy, which the researchers believe is further evidence of a huge mass of material that can be recycled into new stars.
Subaru and Keck II observations revealed that these flows glowed with emission lines, indicating the presence of hydrogen and helium, as expected. However, significant amounts of carbon were also present. The presence of carbon indicates that this cloud contains heavier elements that likely came from long-dead stars.
Another thing that Mammoth 1’s observations discovered is that the two gas streams that pull the galaxy towards it originated from the same quasar. A quasar occurs when a supermassive black hole at the center of a galaxy eats up enough matter to emit a jet of matter and extreme radiation.These jets can eject matter from across the galaxy
The researchers determined that the quasar is likely not in the same galaxy that is pulling in the matter. So this looks like a case of one galaxy reusing material stripped from another.
chemistry, 2023.DOI: 10.1126/science.abj9192
Elizabeth Laine is a writing creature. Her work has been featured in SYFY WIRE, Space.com, Live Science, Grunge, Den of Geek and Forbidden Futures. When she’s not writing, she transforms, paints, and cosplays characters no one has heard of. Follow her on her Twitter @quothravenrayne