Globular clusters 4 billion years younger than previously thought

Globular clusters 4 billion years younger than previously thought
Binary star evolution within a globular cluster. Credit: Mark A. Garlick/University of Warwick

Globular clusters could be up to 4 billion years younger than previously thought, new research led by the University of Warwick has found.

Comprised of hundreds of thousands of densely packed into a tight ball, had been thought to be almost as old as the Universe itself—but thanks to newly developed research models it has been shown that they could be as young as 9 billion years old rather than 13 billion.

The discovery brings into question current theories on how galaxies, including the Milky Way, were formed—with between 150-180 clusters thought to exist in the Milky Way alone—as globular clusters had previously been thought to be almost as old as the Universe itself.

Designed to reconsider the evolution of stars, the new Binary Population and Spectral Synthesis (BPASS) models take the details of evolution within the globular into account and are used to explore the colours of light from old binary star populations—as well as the traces of chemical elements seen in their spectra.

The evolutionary process sees two stars interacting in a binary system, where one star expands into a giant whilst the gravitational force of the smaller star strips away the atmosphere, comprising hydrogen and helium amongst other elements, of the giant. These stars are thought to be formed as the same time as the globular cluster itself.

Through using the BPASS models and calculating the age of the the researchers were able to demonstrate that the globular cluster of which they are part was not as ancient as other models had suggested.

The BPASS models, developed in collaboration with Dr. JJ Eldridge of the University of Auckland, had previously proven effective in exploring the properties of young stellar populations in environments ranging from our Milky Way all the way out to the edge of the Universe.

Discussing the BPASS models and their findings Dr. Elizabeth Stanway, of the University of Warwick's Astronomy and Astrophysics Group and the new finding's lead researcher, said:

"Determining ages for stars has always depended on comparing observations to the models which encapsulate our understanding of how stars form and evolve. That understanding has changed over time, and we have been increasingly aware of the effects of stellar multiplicity—the interactions between stars and their binary and tertiary companions.

Dr. Stanway suggests that the research's findings point to new avenues of enquiry into how massive galaxies, and the stars contained within, are formed:

"It's important to note that there is still a lot of work to do—in particular looking at those very nearby systems where we can resolve individual stars rather than just considering the integrated light of a cluster—but this is an interesting and intriguing result.

"If true, it changes our picture of the early stages of galaxy evolution and where the stars that have ended up in today's massive galaxies, such as the Milky Way, may have formed. We aim to follow up this research in future, exploring both improvements in modelling and the observable predictions which arise from them."


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More information: E R Stanway et al, Reevaluating Old Stellar Populations, Monthly Notices of the Royal Astronomical Society (2018). DOI: 10.1093/mnras/sty1353
Citation: Globular clusters 4 billion years younger than previously thought (2018, June 4) retrieved 25 June 2019 from https://phys.org/news/2018-06-globular-clusters-billion-years-younger.html
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RNP
Jun 04, 2018
If confirmed, this would be a major discovery! (Although I do not understand how it could be consistent with colour-magnitude diagrams of globular clusters). The effects on models of galaxy formation and evolution would be transformative.

I have not looked at it, but an open access copy of the paper can be found here:
https://arxiv.org...8784.pdf

Jun 04, 2018
The discovery brings into question current theories on how galaxies, including the Milky Way, were formed—with between 150-180 clusters thought to exist in the Milky Way alone—as globular clusters had previously been thought to be almost as old as the Universe itself.

Again, like I have been saying for years. Clusters appear older due to tire light climbing out of the gravity well. They are younger than the hose galaxy, having been born from ejections from the galactic core, growing from within all the while, until they themselves grown into galaxies.

Jun 05, 2018
A lot of speculative conclusions (yep, oxymoron) based on too little data. My guess is that there will be many different timescales for many different Globular Clusters, with many different processes of stellar evolution. Just the normal wild & wacky cosmic crapshoot that drives our monkey brains bonkers as we screech our futile demands for an orderly reality.

Hey Tux, since your cult don't do sense. Lacking a coherent explanation for what causes the "birth" of new stars from out of a zero-point singularity.

Here, you can borrow mine.

The gases that make up the stars are the same gasses produced by the biological function of flatulence. Thereforthwith we cannot doubt butt when we are looking at Black Holes, we are observing the anuses of godlings. Who are pooping out all the stars of the universe. Perfectly logical.

My Cosmic Defecation Theory now stands odorously proud next to my Stupid Design Conundrum & Big Brains as an evolutionary dead-end.

You're welcome.

Jun 05, 2018
Again, like I have been saying for years. Clusters appear older due to tire light climbing out of the gravity well.

Since this article has absolutely nothing to do with redshift - what the hell are you babbeling about?

(And no: saying something 'for years' doesn't make it any more right. It just means that you've been incapable of learning for a very long time now)

Jun 05, 2018
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