2023-10-13 11:19:40
Andromeda Galaxy – UNIVERSITY OF HERTFORDSHIRE
MADRID, 13 Oct. (EUROPA PRESS) –
The formation of Andromeda, our neighboring galaxy, was more dramatic and forceful than that of our own Milky Way, according to new research from galactic archeology.
After an intense initial burst of star formation that created the galaxy, a secondary layer of stars was produced between 2 billion and 4.5 billion years ago, probably caused by what scientists call a “wet fusion”: a merger of two gas-rich galaxies that instigates a large amount of star formation.
Scientists have long thought that Andromeda likely experienced a merger of two galaxies, based on the position and motion of individual stars in the galaxy.
New research led by University of Hertfordshire professor Chiaki Kobayashi sheds new light on the nature and impact of such a merger using the chemical composition of stars and explains how the stars and elements were formed throughout the history of Andromeda.
“This is a fantastic example of how galactic archeology can provide new insights into the history of our universe. By analyzing the chemical abundance at different ages of stars in Andromeda we can bring its history to life and better understand its origins,” he said. it’s a statement.
“Although in many ways Andromeda is similar to our own Milky Way (it is a spiral disk galaxy of similar size), our new research confirms that its history is much more intense and dramatic, with bursts of star-forming activity in abundance and two stars different eras of star formation,” he added
The study, accepted for publication in The Astrophysical Journal Letters and available on arXiv, examines elemental abundances in Andromeda, particularly the presence of planetary nebulae: gas and dust that form from the discarded outer layers of dying low-mass stars and branching stars of red giants.
Professor Kobayashi’s theoretical model predicts two different chemical compositions of the stars in the two components of Andromeda’s disk: one has ten times more oxygen than iron, while another has a similar amount of oxygen and iron. This modeling has been confirmed by spectroscopic observations of planetary nebulae and also by those of red giant stars with the James Webb Space Telescope (JWST).
The new study continues Professor Kobayashi’s ongoing research into the origin of elements in the universe. As she explains, “oxygen is one of the so-called alpha elements produced by massive stars. The others are neon, magnesium, silicon, sulfur, argon and calcium.
“Oxygen and argon have been measured with planetary nebulae, but Andromeda is so far away that JWST is required to measure other elements, including iron. In the coming years, JWST and large ground-based telescopes will continue to look at Andromeda, giving more weight to the new findings.”
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