Astronomers from UNIGE have observed the composition of gases in our galaxy and, unlike the models so far, they are not mixed together.
To better understand the history and evolution of the story Milky Way, Astronomers are studying the composition of gases and metals that are an integral part of our galaxy. Three main components have been identified: the original galaxy from outside, the gas between the stars in our galaxies – rich in chemicals – and the dust created by the metals in this gas. So far, theoretical models have combined these three elements into a chemical enrichment process similar to that of the entire solar system.
Today, a team of astronomers from the University of Geneva (UNIGE) show that these gases are not as complex as previously thought, which has a profound effect on the evolution of galaxies today. As a result, Milky Way evolution simulations must change. These results can be read in the journal Nature.
The galaxies are made up of star clusters and are composed mostly of a central galaxy composed of hydrogen and small helium. Unlike gas in galaxies, this gas does not contain metals – in astronomy, all chemical elements heavier than helium are atoms in the form of gas, but they are generally called “metals.”
“The galaxies are fueled by ‘virgin’ gases from outside, which refreshes them and allows them to create new stars,” says Analisa de Sia, a professor of astronomy and first author at the Faculty of Science at the University of Science and Technology. Study. At the same time, the stars burn hydrogen, which they form throughout their lives, and form other elements through nucleation.
When a star reaches its zenith, it expels metals such as iron, zinc, carbon, and silicon and feeds them into the galaxy’s gas. These atoms can be added to dust, especially in cooler and dense rooms of the galaxy.
“When the first Milky Way was created, 10 billion years ago, it had no metal. Then the stars gradually enrich the environment with metals, ”Continued the researcher. When the amount of iron in the gas reaches the level of the sun, astronomers talk about solar metal.
Very unfamiliar environment
The Milky Way construction site will collect stellar metals, dust particles from these metals, but gases from outside the galaxy that regularly enter.
So far, theoretical models are considered to have combined these three elements into the solar system everywhere in our galaxies, and there has been a slight increase in the number of metals in the center of the stars. Institut d’Astrophysique de Paris, Sorbonne University. “We wanted to see this in detail in ultraviolet light Hubble Space Telescope. ”
Spectroscope allows you to differentiate light from stars in individual colors or frequencies, such as prisms or rainbows. In this rotten light, astronomers are particularly interested in drinking lines: “When we look at the star, the metals that form the gas between the stars and ourselves receive a very small amount of light in a natural way. This allows us to identify not only their presence but also their iron content and their abundance. ”
A new method was developed to look at the total metal
The team of scientists spent about 25 hours with Hubble and A. Very large telescope (VLT) in Chile. The problem? Although there are metals, dust cannot be counted on these glasses. So Analisa de Siya’s team developed a new observation method. “It looks at several elements, such as iron, zinc, titanium, silicon, and oxygen, taking into account the overall composition of gas and dust,” says the Geneva researcher. “Then we can analyze the amount of metals in the dust and add to the already estimated by observations to get the total.
Thanks to this dual observation technique, astronomers not only found that the Milky Way area was not the same, but that some of the learned areas were only about 10% of solar metal. “This discovery plays a key role in the creation of galaxies and the evolution of theoretical models,” says Jens-Christan Krogerger, a researcher in astronomy at UNEG. In order for these changes to be incorporated into the metal at various points in the Milky Way, we must now add the resolution and refine the simulations.
These results have a profound effect on our understanding of galaxies and especially our understanding of them. Of course, metals play a vital role in the formation of stars, space dust, molecules, and planets. And now we know that new stars and planets can be created from gases of different stars.
Reference: “Large Metal Differences in the Galactic Intermediate” September 8, 2021; Nature.
DOI: 10.1038 / s41586-021-03780-0