Tag Archives: Cygnus

Green Bank Telescope Maps Cold ‘Dark’ Gas in Cygnus X

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An astronomer utilizing the Green Bank Telescope (GBT) has developed an extensive map of carbon monoxide (CO) and dark molecular gas in star-forming complexes, particularly in Cygnus X.

These images illustrate the location of CO-dark molecular gas within Cygnus X. Image credit: NSF/AUI/NSF’s NRAO/P.Vosteen.

For decades, scientists have recognized that most new stars are birthed in frigid clouds of molecular hydrogen gas.

A significant portion of this molecular hydrogen remains elusive to most telescopes as it fails to emit easily detectable light.

Astronomers have typically sought these clouds by examining carbon monoxide (CO), a molecule that serves as a glowing signal for star-forming regions.

However, it has been uncovered that CO houses a considerable amount of “non-glowing” gas conducive to star formation.

This concealed material, referred to as CO-dark molecular gas, has represented one of astronomy’s most significant blind spots.

In a fresh study, NRAO astronomer Kimberly Emig and her team mapped this hidden gas across extensive sections of the sky, using radio spectral lines from atomic recombination known as carbon radio recombination lines (CRRLs).

Their map encompasses Cygnus X, a star-forming region located approximately 5,000 light-years away in the constellation Cygnus.

“It’s akin to suddenly switching on a light in a room and discovering various structures that were previously unseen,” Dr. Emig remarked.

The newly constructed map unveils a sprawling network of arcs, ridges, and webs of dark gas permeating Cygnus X.

These formations indicate where star-forming materials accumulate and evolve before becoming noticeable as molecular clouds in CO.

The authors demonstrated that these faint carbon signals, observed at very low radio frequencies, serve as an extraordinarily powerful instrument for uncovering hidden gas that directly correlates ordinary matter with the birth of new stars.

They found that this dark gas is not static; instead, it flows, shifts, and moves at rates much faster than previously recognized. These dynamics influence the stellar formation rate.

Moreover, they discovered that the intensity of these carbon lines is directly connected to the intense starlight bathing the area, emphasizing the significant role radiation plays in galactic recycling.

“By illuminating the invisible, we can trace how the raw ingredients in our galaxy transform from simple atoms into complex molecular structures that will ultimately become stars, planets, and potentially life,” Dr. Emig stated.

“This marks merely the beginning of comprehending an otherwise unseen force.”

Find the results published in the October 17th edition of the Astrophysical Journal.

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Kimberly L. Emig et al. 2025. The cold dark gas of Cygnus X: the first large-scale mapping of low-frequency carbon recombination lines. APJ 992, 216; doi: 10.3847/1538-4357/adfa17

Source: www.sci.news

Astronomers Propose that X-ray and Ultraviolet Radiation Impact the Protoplanetary Disk in Cygnus OB2

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Cygnus OB2 is the giant young stellar association closest to the Sun.

In this new composite image, Chandra data (purple) shows the diffuse X-ray emission and young stars of Cygnus OB2, along with infrared data (red, green, blue, cyan) from NASA's now-retired Spitzer Space Telescope reveals young stars. And it creates cold dust and gas throughout the region. Image credits: NASA / CXC / SAO / Drake others. / JPL-California Institute of Technology / Spitzer / N. Walk.

At a distance of approximately 1,400 parsecs (4,600 light years), Cygnus OB2 It is a huge young body closest to the Sun.

It contains hundreds of double stars and thousands of low-mass stars.

Dr. Mario Giuseppe Guarcero of the National Institute of Astrophysics, Dr. Juan Facundo Albacete Colombo of the University of Rio Negro, and colleagues used NASA's Chandra X-ray Observatory to study various regions of Cygnus OB2. observed.

This deep observation mapped the diffuse X-ray glow between the stars and also provided an inventory of young stars within the cluster.

This inventory was combined with other inventories using optical and infrared data to create the best survey of young stars within the association.

“These dense stellar environments are home to large amounts of high-energy radiation produced by stars and planets,” the astronomers said.

“X-rays and intense ultraviolet radiation can have devastating effects on planetary disks and systems that are in the process of forming.”

The protoplanetary disk around the star naturally disappears over time. Part of the disk falls onto the star, and some is heated by X-rays and ultraviolet light from the star and evaporates in the wind.

The latter process, known as photoevaporation, typically takes 5 million to 10 million years for an average-sized star to destroy its disk.

This process could be accelerated if there is a nearby massive star that produces the most X-rays and ultraviolet light.

researchers Found Clear evidence that protoplanetary disks around stars actually die out much faster when they approach massive stars that produce large amounts of high-energy radiation.

Also, in regions where stars are more densely packed, the disk dies out faster.

In the region of Cygnus OB2, which has less high-energy radiation and fewer stars, the proportion of young stars with disks is about 40%.

In regions with higher-energy radiation and more stars, the proportion is about 18%.

The strongest influence, and therefore the worst location for a star to become a potential planetary system, is within about 1.6 light-years of the most massive star in the cluster.

In another study, the same team I looked into it Characteristics of the diffuse X-ray emission of Cygnus OB2.

They discovered that the high-energy, diffuse radiation originates from regions where winds of gas blown from massive stars collide with each other.

“This causes the gas to become hot and generate X-rays,” the researchers said.

“The low-energy release is likely caused by gas within the cluster colliding with gas surrounding the cluster.”

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MG Guarcero others. 2024. Photoevaporation and close encounters: How does the environment around Cygnus OB2 affect the evolution of the protoplanetary disk? APJS 269, 13; doi: 10.3847/1538-4365/acdd67

JF Albacete vs Colombo others. 2024. Diffuse X-ray emission in the Cygnus OB2 coalition. APJS 269, 14;doi: 10.3847/1538-4365/acdd65

Source: www.sci.news

Astrophysicists discover that black hole-hosting binary star V404 Cygnus is part of a triple system

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V404 Cygnus, an X-ray binary star that hosts a low-mass black hole, has a wide echelon with a tertiary companion at least 3,500 astronomical units (AU) away from the inner binary, according to MIT astrophysicists. It is said to be part of a triple star.

V404 SIGNI. Image credit: Verge others., doi: 10.1038/s41586-024-08120-6.

V404 Cygni is located approximately 7,800 light-years away in the constellation Cygnus.

This system first attracted attention more than 80 years ago, during the 1938 nova explosion.

Another eruption occurred in 1989 and was discovered by the Japanese X-ray satellite Ginga and high-energy instruments aboard the Mir space station.

The 1989 explosion, known as Nova Cygnus 1989, was pivotal in the study of black holes.

Until then, astronomers had known of only a handful of objects that could be black holes, and V404 Cygnus was one of the most likely candidates.

V404 Cygnus is known to host a central stellar-mass black hole in the act of consuming a small star that spirals very close to the black hole every 6.5 days. This is a configuration similar to most binary star systems.

But new research suggests there's a second star orbiting the black hole, albeit much further away.

“Most black holes are thought to be formed by violent explosions of stars, but this discovery helps cast doubt on that,” said Kevin Burge, a researcher at the Massachusetts Institute of Technology (MIT). Ta.

“This system is very interesting for the evolution of black holes, and also raises the question of whether triples exist.”

Artist's impression of V404 Cygnus: The central black hole (black dot) is consuming a nearby star (orange object on the left), while the second star (white flash at the top) is far away orbiting a distance of Image credit: Jorge Lugo.

Burge and his colleagues estimate that the third companion star orbits the V404 Cygnus black hole every 70,000 years.

The fact that black holes appear to exert a gravitational pull on distant objects raises questions about the origins of black holes themselves.

Black holes are thought to be formed by violent explosions of dying stars. This is a process known as a supernova, in which a star releases a huge amount of energy and light in one final burst before collapsing into an invisible black hole.

But the team's findings suggest that if the newly observed black hole had originated from a typical supernova, the energy released before it collapsed would have kicked loosely bound objects around it. It suggests that it might have been.

So the second outer star shouldn't be hanging around yet.

Instead, the authors believe that the V404 Cygnus black hole formed through a more gentle process of direct collapse, in which the star simply collapsed and formed the black hole without a final, dramatic flash. I think it might be.

Such a benign origin poses little impediment to loosely bound, distant objects.

Because V404 Cygnus contains a very distant star, this suggests that the black holes in this system were born through a more gradual, direct collapse.

And while astronomers have observed more violent supernovae for centuries, this triple system may be the first evidence of a black hole formed from this more gentle process.

In addition to providing clues about the black hole's origin, the outer star also revealed the age of the system.

Astrophysicists observed that the outer star happened to be in the process of becoming a red giant, a stage that occurs at the end of a star's life.

Based on this star's evolution, they determined that the outer star was about 4 billion years old.

Considering that the neighboring stars were born at about the same time, they conclude that the components of the binary star are also 4 billion years old.

“This has never been done before with old black holes,” Dr. Burge says.

“Thanks to this discovery, we now know that V404 Cygnus is part of a triple star. It may have formed by direct collapse, and it formed about 4 billion years ago.”

of findings Published in this week's magazine nature.

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KB barge others. The black hole low-mass X-ray binary V404 Cygnus is part of a wide triple. naturepublished online October 23, 2024. doi: 10.1038/s41586-024-08120-6

Source: www.sci.news