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What are the ingredients that went into the galaxy blender to create the Milky Way?

Simulation of a collision between a young Milky Way and a small galaxy. Credit: Dr Tobias Buck (AIP / MPIA / NYU)

Initially, the Milky Way was like a giant smoothie, like a galaxy of billions of stars, with a huge blender filled with a lot of gas.


However, a new study separates this mixture by analyzing individuals. Performer To identify which occurred inside the galaxy and which started life outside.

“The Milky Way is our home galaxy, but we still don’t know how it was formed and evolved,” said the ARC Center of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D) and the Australian National University (ASTRO 3D). ANU) researcher Sven Buder said. ).

His dissertation is this week Monthly Notification of the Royal Astronomical SocietyIt helps us to analyze the light from the stars in detail and understand which elements were included in the creation of the Milky Way that we know today.

“The Milky Way ate a lot of small things Galaxy But until recently, there was certainly not enough evidence to say, “says Buder.

“It’s because simple images of our Milky Way stars look the same. It doesn’t matter if they were born inside or outside the galaxy, and blended into the galaxy.”

Buder and colleagues from the Galactic Archeology and HERMES (GALAH) team use the Anglo-Australian Telescope (AAT), Australia’s largest optical telescope at the Siding Spring Observatory, to HERMES (high efficiency) light from over 600,000 stars. And resolution) divided into wavelengths. Multi-element spectrometer) equipment.

What are the ingredients that went into the galaxy blender to create the Milky Way?

You can distinguish between stars born in the Milky Way (green) and outside (yellow) simply by looking at how abundant sodium, iron, magnesium, and manganese are in the stars. Credit: Dr Tobias Buck (AIP / MPIA / NYU)

This effectively creates a rainbow of 600,000 stars called the spectrum.

Within each of these rainbows is a specific band of light that changes depending on the chemical composition of the star. It’s like a small unique barcode.

“If the image is worth 1000 words, these spectra are worth more than 1000 photos,” says Buder. “By” scanning “the barcodes of these stars, we can see how rich the 30 elements such as sodium, iron, magnesium and manganese are and how they appear at different concentrations depending on where the star was born. I measured it. “

This discovery is an early step in reconstructing the “childhood” photographs of the Milky Way to understand the size of galaxies consumed in the process.

“It may also help us understand how some of the galaxy features we know today were born,” says Buder.

One mystery that new observations may help solve is why there are two different groups of stars on the disc that we see as “milky” bands in the night sky.

What are the ingredients that went into the galaxy blender to create the Milky Way?

The Milky Way has two different groups of stars, one older than the other. Old stars have moved to appear to bulge from the Milky Way’s principal plane, while young stars form much thinner bands in the plane. Credit: Dr Tobias Buck (AIP / MPIA / NYU)

“The Milky Way in the night sky is a familiar sight, and when you look at it, you’re actually staring at the center of the galaxy, which is home to billions of stars,” says Buder.

“But we see a group of two stars, one much older than the other. The old stars have moved to appear to bulge from the main plane of the Milky Way, while the young stars, airplane.

“But I don’t know why this happened. The latest discoveries about the wreckage of a giant galaxy collision may help us understand,” says Buder.

Buder’s paper provides up-to-date revelations that rely on data from the Gaia project. This is an ambitious satellite mission to graph a 3D map of the Milky Way to help you understand the orbit, composition, formation, and evolution of the Milky Way.

Gaia satellite measurements previously helped find potential stars outside the galaxy. This is because they still behave differently than the typical Milky Way stars. However, the origin of extragalactic stars can only be confirmed by their chemical fingerprints.

The GALAH survey is Australia-led to acquire the highest spectral resolution multidimensional dataset of over 1 million stars of all ages and locations in the Milky Way to track the entire history of the galaxy using the HERMES device. It is a scale observation program.


Play a detective on a galactic scale: a huge new dataset solves the mysteries of multiple Milky Ways


For more information:
Sven Buder et al, GALAH Survey: Chemical Tagging and Chronochemodynamics of Attached Halo Stars by GALAH + DR3 and Gaiae DR3, Monthly Notification of the Royal Astronomical Society (2021). DOI: 10.1093 / mnras / stab3504

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Quote: What are the ingredients that went into the galaxy blender to create the Milky Way? (February 22, 2022) Obtained February 22, 2022 from https: //phys.org/news/2022-02-ingredients-galactic-blender-milky.html

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What are the ingredients that went into the galaxy blender to create the Milky Way?

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