Astronomers have just discovered a new secret about the Milky Way

Astronomers have developed a rather advanced knowledge of the galaxies that cover our universe. But ours, the Milky Way, still hides secrets. It has also just unveiled a new one: a ring of metal-rich stars surrounding the galactic bar.

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[EN VIDÉO] The Milky Way: the simulation of the formation of a galaxy
This movie shows a computer simulation of a galaxy like the Milky Way. The film winds through simulated time, from 13 billion years in the past to today. The main galaxy grows as many smaller galaxies merge with it. Heracles resembles one of the small galaxies that merged with the Milky Way early in the process. © Ted Mackereth, EAGLE

When we look up at the sky at night, we trust in our own eyes to reveal to us the beauties of the universe. That astronomersthey imagined first telescopes which opened new horizons for them. Today, they even have instruments that allow them to look beyond the visible. In the infrared domain e.g. And thus to cross the barriers of dust that have long hidden our heart The Milky Way.

Remember that our Earth is sailing somewhere in one arm of our spiral galaxy. In the plane of his disk. Difficult, under these conditions, to perceive the structure of The Milky Way. More so its internal structure. But over the last decade, astronomers have taken advantage of a lot of new observational data to feed their simulations and build a model that is true to reality. That of a so-called barred galaxy. Which houses a band ofstars centers – a rod – coming out of a bulge – the bulb.

Today some Max Planck Institute researchers (Germany) bring new details to this description. Thanks to a study conducted in wavelengths of near infrared on it database of the Apogee Mission. This one is studying in high solution all star components of the Milky Way. By combining this data with those returned by the Gaia mission, which measures positions and movements of a billion stars, scientists were almost there. All they needed were groundbreaking computer models to look out over the galactic bulge and probe areas that had hitherto been inaccessible. What to reveal in a new way orbit of 30,000 stars located in the inner areas of the Milky Way.

Trace the history of the formation of the Milky Way

From there, astronomers have constructed maps of the density, metallicity and age of the stars in this region of the Milky Way. Map showing, around the central bar of our galaxy, a ring structure richer on metals understand, in elements heavier thanhydrogen andhelium – and consists of younger stars, about 7 billion years old, concentrated on the galactic plane.

Similar rings have already been observed inside others galaxies. But researchers were still wondering if there was one in ours. They now have the answer.

An answer that informs them a little more about the history of the formation of our Milky Way. Astronomers estimate that the galactic bar was formed at least 7 billion years ago. The stars that make up the newly observed ring must have continued to form from an influx of gas after the installation of this bar.

The question that remains unanswered is the question of the possible connection between the ring discovered by researchers at the Institute Max Plank and spiralarme of the Milky Way. Is gas being led into our galaxy to burn for star formation at the core of the ring, as may be the case in other spiral galaxies? To answer this, astronomers will not only need additional data, but also more accurate models.

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