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Dark stars: Scientists discover a new type of star powered by dark matter

Stars have long fascinated humanity, radiating brilliance from the vast expanse of space through the process of fusion, where atoms fuse together and release energy. “Dark stars” turn this imagery inside out and may be the long-hunted source of dark matter.

An incredible discovery conducted by a team of three astrophysicists suggests the existence of an alternative source of stellar power behind these dark stars.

Analyzing images captured by the James Webb Space Telescope (JWST), the researchers have identified three exceptionally bright objects that may be what they call “dark stars.”

The annihilation of dark matter particles could potentially fuel these theoretical celestial bodies. It would make them much larger and more radiant than our sun.

Has the source of dark matter finally been identified?

Confirming the existence of dark stars would not only revolutionize our understanding of stellar evolution, but also provide crucial insights into the elusive nature of dark matter. This is one of the most profound unsolved mysteries in the realm of physics.

Leading this captivating research endeavor are Katherine Freese from The University of Texas at Austin. She worked in collaboration with Cosmin Ilie and Jillian Paulin ’23 from Colgate University.

“Discovering a new type of star is pretty interesting all by itself but discovering it’s dark matter that’s powering this—that would be huge,” expressed Freese, who serves as the director of the Weinberg Institute for Theoretical Physics and holds the prestigious Jeff and Gail Kodosky Endowed Chair in Physics at UT Austin.

Dark stars, dark matter, and WIMPs

Dark matter, which constitutes about 25% of the universe, has long perplexed scientists due to its elusive nature. Researchers believe it comprises a novel type of elementary particle. The ongoing quest to detect and understand these particles continues. One of the leading candidates for dark matter particles is Weakly Interacting Massive Particles (WIMPs).

When WIMPs collide, they self-annihilate, releasing heat that permeates collapsing hydrogen clouds, transforming them into luminous dark stars. The identification and characterization of supermassive dark stars hold the potential to unravel the secrets of dark matter by studying their observable properties.

The research findings have been published in the esteemed Proceedings of the National Academy of Sciences.

The scientists need to conduct more research

To confirm the dark star hypothesis, the team plans to conduct follow-up observations using the JWST, primarily focusing on the spectroscopic properties of the candidate objects.

By examining variations in light intensity at specific frequencies, such as dips or excesses, these investigations can provide crucial evidence to validate the existence of dark stars.

Moreover, confirming the presence of dark stars may also help resolve a perplexing puzzle posed by the JWST. The telescope’s observations suggest the existence of an unusually high number of large galaxies in the early universe, which challenges the predictions of the standard model of cosmology.

“It’s more likely that something within the standard model needs tuning because proposing something entirely new, as we did, is always less probable,” Freese acknowledged. “But if some of these objects that look like early galaxies are actually dark stars, the simulations of galaxy formation agree better with observations.”

Not galaxies after all

Originally identified as galaxies in December 2022 by the JWST Advanced Deep Extragalactic Survey (JADES), the three candidate dark stars, named JADES-GS-z13-0, JADES-GS-z12-0, and JADES-GS-z11-0, have now become subjects of intense scientific inquiry.

Spectroscopic analysis by the JADES team has confirmed that these objects were observed between approximately 320 and 400 million years after the Big Bang. That makes them among the earliest entities ever detected.

“When we look at the James Webb data, there are two competing possibilities for these objects,” Freese explained. “One is that they are galaxies containing millions of ordinary, population-III stars. The other is that they are dark stars. And believe it or not, one dark star has enough light to compete with an entire galaxy of stars.”

10 billion times brighter than the Sun

Theoretically, dark stars have the potential to grow to several million times the mass of the Sun. They may also emit luminosity up to 10 billion times brighter than our own star.

“We predicted back in 2012 that supermassive dark stars could be observed with JWST,” stated Ilie, an assistant professor of physics and astronomy at Colgate University. “As shown in our recently published PNAS article, we already found three supermassive dark star candidates when analyzing the JWST data for the four high-redshift JADES objects spectroscopically confirmed by Curtis-Lake et al, and I am confident we will soon identify many more.”

The concept of dark stars originated through a series of discussions between Freese and Doug Spolyar. Mr. Spolyar is a former graduate student at the University of California, Santa Cruz.

Pondering over the influence of dark matter on the first stars that emerged in the universe, they reached out to Paolo Gondol. He is an astrophysicist at the University of Utah, who subsequently joined the team.

After years of development and exploration, they published their initial paper on this groundbreaking theory in the journal Physical Review Letters back in 2008.

Freese, Spolyar, and Gondolo construct a model

Deep within the primordial protogalaxies, dense clumps of dark matter coexist with hydrogen and helium gas clouds. As the gas cools, it collapses, drawing in dark matter particles along with it.

With increasing density, the dark matter particles progressively annihilate, releasing additional heat. This thermal energy prevents the gas from collapsing into a sufficiently dense core to sustain fusion reactions. This is what we see in conventional stars.

Instead, the gas continues to accumulate, intertwining with dark matter and giving rise to enormous, voluminous structures — dark stars. Ordinary stars concentrate their power within their core. Dark stars disperse their energy more evenly throughout their entire structure.

Funding for this pioneering research endeavor was provided by the U.S. Department of Energy’s Office of High Energy Physics program and the Vetenskapsradet (Swedish Research Council) at the Oskar Klein Centre for Cosmoparticle Physics at Stockholm University.

More about dark matter

Dark matter is a mysterious and elusive form of matter that constitutes a significant portion of the universe. It does not interact with light or other forms of electromagnetic radiation.

This makes it invisible and difficult to detect. Scientists have inferred the existence of dark matter through its gravitational effects on visible matter and the structures of the cosmos.

Properties and composition

Scientists believe dark matter is non-baryonic. This indicates that it does not comprise the ordinary particles that make up atoms, such as protons and neutrons.

Instead, it is hypothesized to consist of peculiar particles that have yet to be directly observed or identified. These particles do not emit, absorb, or reflect light, hence the term “dark” matter.

Cosmological significance

Dark matter plays a crucial role in shaping the universe’s structure and evolution. Through its gravitational influence, it forms the scaffolding upon which galaxies, galaxy clusters, and larger cosmic structures assemble and grow over billions of years.

It provides the gravitational glue that binds these structures together. In doing so, dark matter prevents them from dispersing due to the expansion of the universe.

Evidence for dark matter

Several lines of evidence support the existence of dark matter. One compelling piece of evidence comes from observations of galactic rotation curves. These curves describe the velocities of stars and gas within galaxies as a function of their distance from the galactic center.

Observations consistently reveal that the velocities remain relatively constant or even increase with distance. This contrasts with what one would expect based on visible matter alone. The additional mass and gravitational pull of dark matter are required to explain these observations.

Another important piece of evidence comes from gravitational lensing, where the gravity of massive objects bends the path of light. The precise measurements of this bending effect indicate the presence of additional mass in the form of dark matter. This distorts the observed lensing patterns.

Detection efforts

Scientists have been actively searching for direct evidence of dark matter particles using various detection methods. One approach involves employing underground detectors to search for rare interactions between dark matter particles and regular matter. These detectors are typically shielded from cosmic rays to minimize background noise.

Another method involves studying high-energy particle collisions in large particle accelerators, such as the Large Hadron Collider (LHC). Scientists hope that these collisions might produce bizarre particles. These would include dark matter particles, which would leave behind distinct signatures in the detector.

Despite the extensive efforts and progress made in the study of dark matter, its exact nature and composition remain elusive. Scientists continue to explore new avenues of research, develop innovative detection techniques, and refine existing theories in the quest to unravel the mysteries of dark matter.

Dark matter represents a significant enigma in modern physics and cosmology. Its presence, inferred through its gravitational effects, has a profound impact on the structure and evolution of the universe.

As scientific understanding and detection techniques advance, the elusive nature of dark matter continues to intrigue and challenge researchers. This important missing piece in cosmology is driving the scientific community to unlock its secrets and shed light on the fundamental workings of our universe.

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