2023-07-15 06:00:06
By peering into the heart of the Milky Way, astronomers have discovered that some of the oldest stars in our galaxy seem to spend their long lives stably near the galactic center. These observations are contradictory with previous estimates and observations of astronomers. Their trajectories and their position in relation to the Sun have been highlighted by an international team of researchers during the largest observation this day of these old stars.
Artistic impression of ancient stars in the inner region of the Milky Way (The Milky Way (also called “our galaxy”, or sometimes…).
Background image left: ESA/Gaia,
Artist’s impression: Amanda J. Smith and Anke Arentsen, Institute of Astronomy (Astronomy is the science of observing the stars, seeking to explain…), Cambridge, CC BY 4.0.
The Pristine Inner Galaxy Survey (PIGS) team, led by Dr Anke Arentsen from the University of Cambridge, presented the new findings at the National Astronomical Congress 2023 at Cardiff University (Cardiff University (English: Cardiff University; Welsh: Prifysgol…).
Some stars born in the first billion years after the Big Bang (The Big Bang is the dense and hot period that the universe experienced there are…) are still present today. These ancient stars, whose chemical composition is essentially made up of hydrogen (Hydrogen is a chemical element with symbol H and atomic number 1.) and helium, allow us to better understand the galaxies at the time of their formation. They contain fewer heavy elements than younger stars like the Sun. Typically, astronomers look for these ancient stars far from the plane of the Milky Way’s disk, in the low-density halo around our galaxie (Galaxies is a quarterly French magazine dedicated to science fiction. With…), where they are easier to find.
According to models of galaxy formation, the oldest stars are concentrated in the dense parts of the center of the Milky Way. But finding these stars in this region is complex, due to the interstellar dust that blocks our line of sight to the center of the galaxy, and the rarity of older stars compared to the overwhelming majority of their younger ones.
For the PIGS project, Dr. Arentsen and her team used a special imaging filter on the Canada-France-Hawaii (CFHT) Telescope (A telescope, (from the Greek tele meaning “far” and skopein meaning…) to pre-select candidate stars. These were confirmed by spectroscopic observations on the Anglo-Australian Telescope (AAT), resulting in the largest ensemble. large ensembles are typically…) detailed observations for stars in the Milky Way.
By combining PIGS observations with data from the Gaia space mission, the team studied the movement of these ancient stars in the Milky Way. It was previously observed that the older the stars, the more chaotic their movements. Nevertheless, even the oldest stars found show some stability around the center of the galaxy. They spend most of their lives in the inner galaxy, in a sphere that extends only halfway between the galactic center and the Sun.
Dr Arentsen enthuses: “It’s exciting to think that we’re observing stars that formed during the early phases of the Milky Way, which until then were largely inaccessible. These stars were probably formed less than a billion years ago. years after the Big Bang, they are therefore relics of the early Universe.” Regarding the future of these observations, she says, “The data available for these ancient objects is increasing rapidly. I look forward to seeing what we learn about these early stars in the next few years!”
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#Discoveries #stars #unexpected #behavior #heart #galaxy