Science Current Events | Science News |

In The Heart Of Cygnus, NASA's Fermi Reveals A Cosmic-ray Cocoon

November 29, 2011
The constellation Cygnus, now visible in the western sky as twilight deepens after sunset, hosts one of our galaxy's richest-known stellar construction zones. Astronomers viewing the region at visible wavelengths see only hints of this spectacular activity thanks to a veil of nearby dust clouds forming the Great Rift, a dark lane that splits the Milky Way, a faint band of light marking our galaxy's central plane.

Located in the vicinity of the second-magnitude star Gamma Cygni, the star-forming region was named Cygnus X when it was discovered as a diffuse radio source by surveys in the 1950s. Now, a study using data from NASA's Fermi Gamma-ray Space Telescope finds that the tumult of star birth and death in Cygnus X has managed to corral fast-moving particles called cosmic rays.

Cosmic rays are subatomic particles -- mainly protons -- that move through space at nearly the speed of light. In their journey across the galaxy, the particles are deflected by magnetic fields, which scramble their paths and make it impossible to backtrack the particles to their sources.

Yet when cosmic rays collide with interstellar gas, they produce gamma rays -- the most energetic and penetrating form of light -- that travel to us straight from the source. By tracing gamma-ray signals throughout the galaxy, Fermi's Large Area Telescope (LAT) is helping astronomers understand the sources of cosmic rays and how they're accelerated to such high speeds. In fact, this is one of the mission's key goals.

The galaxy's best candidate sites for cosmic-ray acceleration are the rapidly expanding shells of ionized gas and magnetic field associated with supernova explosions. For stars, mass is destiny, and the most massive ones -- known as types O and B -- live fast and die young.

They're also relatively rare because such extreme stars, with masses more than 40 times that of our sun and surface temperatures eight times hotter, exert tremendous influence on their surroundings. With intense ultraviolet radiation and powerful outflows known as stellar winds, the most massive stars rapidly disperse their natal gas clouds, naturally limiting the number of massive stars in any given region.

Which brings us back to Cygnus X. Located about 4,500 light-years away, this star factory is believed to contain enough raw material to make two million stars like our sun. Within it are many young star clusters and several sprawling groups of related O- and B-type stars, called OB associations. One, called Cygnus OB2, contains 65 O stars -- the most massive, luminous and hottest type -- and nearly 500 B stars.

Astronomers estimate that the association's total stellar mass is 30,000 times that of our sun, making Cygnus OB2 the largest object of its type within 6,500 light-years. And with ages of less than 5 million years, few of its most massive stars have lived long enough to exhaust their fuel and explode as supernovae.

Intense light and outflows from the monster stars in Cygnus OB2 and from several other nearby associations and star clusters have excavated vast amounts of gas from their vicinities. The stars reside within cavities filled with hot, thin gas surrounded by ridges of cool, dense gas where stars are now forming. It's within the hollowed-out zones that Fermi's LAT detects intense gamma-ray emission, according to a paper describing the findings that was published in the Nov. 25 edition of the journal Science.

"We are seeing young cosmic rays, with energies comparable to those produced by the most powerful particle accelerators on Earth. They have just started their galactic voyage, zig-zagging away from their accelerator and producing gamma rays when striking gas or starlight in the cavities," said co-author Luigi Tibaldo, a physicist at Padova University and the Italian National Institute of Nuclear Physics.

The energy of the gamma-ray emission, which is measured up to 100 billion electron volts by the LAT and even higher by ground-based gamma-ray detectors, indicates the extreme nature of the accelerated particles. (For comparison, the energy of visible light is between 2 and 3 electron volts.) The environment holds onto its cosmic rays despite their high energies by entangling them in turbulent magnetic fields created by the combined outflows of the region's numerous high-mass stars.

"These shockwaves stir the gas and twist and tangle the magnetic field in a cosmic-scale jacuzzi so the young cosmic rays, freshly ejected from their accelerators, remain trapped in this turmoil until they can leak into quieter interstellar regions, where they can stream more freely," said co-author Isabelle Grenier, an astrophysicist at Paris Diderot University and the Atomic Energy Commission in Saclay, France.

The well known Gamma Cygni supernova remnant - so named for its proximity to the star -- also lies within this region; astronomers estimate its age at about 7,000 years. The Fermi team considers it possible that the supernova remnant spawned the cosmic rays trapped in the Cygnus X "cocoon," but they also suggest an alternative scenario where the particles became accelerated through repeated interaction with shockwaves produced inside the cocoon by powerful stellar winds.

"Whether the particles further gain or lose energy inside this cocoon needs to be investigated, but its existence shows that cosmic-ray history is much more eventful than a random walk away from their sources," Tibaldo added.

Fermi is providing a never-before-seen glimpse of the early life of cosmic rays, long before they diffuse into the galaxy at large. Astronomers know of a dozen stellar clusters at least as young and rich as Cygnus OB2, including the Arches and Quintuplet clusters near the galaxy's center. Energetic gamma rays are detected in the vicinity of several of them, so perhaps they also corral cosmic rays in their own high-energy cocoons.

NASA's Fermi is an astrophysics and particle physics partnership managed by NASA's Goddard Space Flight Center in Greenbelt, Md., and developed in collaboration with the U.S. Department of Energy, with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the United States.

Related Links:

Nursery of Giants Captured in New Spitzer Image

NASA's Fermi Telescope Detects Gamma-Rays From 'Star Factories' in Other Galaxies

What is Cygnus X?

NASA's Goddard Space Flight Center

Related Cosmic Rays Current Events and Cosmic Rays News Articles

How to estimate the magnetic field of an exoplanet?
located outside the Solar system and orbits a different star.

Himalaya tectonic dam with a discharge
The Himalaya features some of the most impressive gorges on Earth that have been formed by rivers. The geologic history of the famous Tsangpo Gorge, in the eastern Himalaya, now needs to be rewritten.

Caltech geologists discover ancient buried canyon in South Tibet
A team of researchers from Caltech and the China Earthquake Administration has discovered an ancient, deep canyon buried along the Yarlung Tsangpo River in south Tibet, north of the eastern end of the Himalayas.

Sun's rotating 'magnet' pulls lightning towards UK
The Sun may be playing a part in the generation of lightning strikes on Earth by temporarily 'bending' the Earth's magnetic field and allowing a shower of energetic particles to enter the upper atmosphere.

Permafrost soil: Possible source of abrupt rise in greenhouse gases at end of last Ice Age
Scientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have identified a possible source of carbon dioxide (CO2) and other greenhouse gases that were abruptly released to the atmosphere in large quantities around 14,600 years ago.

Laser experiments mimic cosmic explosions and planetary cores
Researchers are finding ways to understand some of the mysteries of space without leaving earth.

UNH scientist: Cosmic rays threaten future deep-space astronaut missions
Crewed missions to Mars remain an essential goal for NASA, but scientists are only now beginning to understand and characterize the radiation hazards that could make such ventures risky, concludes a new paper by University of New Hampshire scientists.

Tiny 'nanoflares' might heat the Sun's corona
Why is the Sun's million-degree corona, or outermost atmosphere, so much hotter than the Sun's surface? This question has baffled astronomers for decades.

Earth's magnetic field could flip within a human lifetime
Imagine the world waking up one morning to discover that all compasses pointed south instead of north.

First dark matter search results from Chinese underground lab hosting PandaX-I experiment
Scientists across China and the United States collaborating on the PandaX search for dark matter from an underground lab in southwestern China report results from the first stage of the experiment in a new study published in the Beijing-based journal SCIENCE CHINA Physics, Mechanics & Astronomy.
More Cosmic Rays Current Events and Cosmic Rays News Articles

Cosmic Rays

Cosmic Rays
by Michael W. Friedlander (Author)

Day in and day out, cosmic rays from the far reaches of space pass through our bodies, yet modern astrophysics has still to unlock all their secrets. Though many details about cosmic rays remain enigmatic, next to electromagnetic radiation they convey more information about the universe beyond the solar system than any other source. They provide us with information about energetic explosions elsewhere in our galaxy and perhaps beyond, and they tell us a great deal about the contents of our own galaxy, through which they pass in reaching us. Illustrating the beautiful symmetry of nature, they shed light on the tiny dimensions of atomic nuclei as well as the immense scale of galaxies. Friedlander's engaging tale of this peculiar rain of charged particles begins with their discovery early...

The Cosmic Doctrine

The Cosmic Doctrine
by Dion Fortune (Author)

Over seventy-two years ago, beginning at the Vernal Equinox in Glastonbury, Fortune started receiving communications from the Inner Planes concerning the creation of the universe, the evolution of humanity, natural law, the evolution of consciousness, and the nature of mind. This is her record, in a revised edition, and includes previously unpublished material that is still relevant today!

Cosmic Rays

Cosmic Rays
by Bruno Rossi (Author)

Written by the scientist who created or imrproved the x-ray machine.

Cosmic Rays in the Earth's Atmosphere and Underground (Astrophysics and Space Science Library)

Cosmic Rays in the Earth's Atmosphere and Underground (Astrophysics and Space Science Library)
by Lev Dorman (Author)

The present monograph as well as the next one (Dorman, M2005) is a result of more than 50 years working in cosmic ray (CR) research. After graduation in December 1950 Moscow Lomonosov State University (Nuclear and Elementary Particle Physics Division, the Team of Theoretical Physics), my supervisor Professor D. I. Blokhintsev planned for me, as a winner of a Red Diploma, to continue my education as an aspirant (a graduate student) to prepare for Ph. D. in his very secret Object in the framework of what was in those time called the Atomic Problem. To my regret the KGB withheld permission, and I, together with other Jewish students who had graduated Nuclear Divisions of Moscow and Leningrad Universities and Institutes, were faced with a real prospect of being without any work. It was our...

High Energy Cosmic Rays (Springer Praxis Books / Astronomy and Planetary Sciences)

High Energy Cosmic Rays (Springer Praxis Books / Astronomy and Planetary Sciences)
by Todor Stanev (Author)

Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

Flagstaff & Sedona: 50 Favorite Hikes

Flagstaff & Sedona: 50 Favorite Hikes
by Cosmic Ray (Author), Cosmic Ray (Editor), Cosmic Ray (Editor)

15th edition, 2014 guide to the best of the best Flagstaff and Sedona day hikes. Be sure to read old reviews for many reader comments. Every hike a guaranteed winner. No filler. Accurate, down to earth, easy to read maps. Each description features contour profile, distance, time, effort required, type (out and back, loop, etc.) and best season to hike. Included are detailed directions to the trailhead plus a verbal description of each hike. There is a critter foot finder guide to the footprints of many of the animals found in northern Arizona and hiking directions to vortex sites around Sedona.

Cosmic Rays at Earth

Cosmic Rays at Earth
by P.K.F. Grieder (Editor)

In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery.
Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary...

Cosmic Rays: Three Lectures

Cosmic Rays: Three Lectures
by R. A. Millikan (Author)

The Chilling Stars: A Cosmic View of Climate Change

The Chilling Stars: A Cosmic View of Climate Change
by Henrik Svensmark (Author), Nigel Calder (Contributor)

Scientists agree that the earth has become hotter over the last century. But on the causes, despite what looks to the public mind like a consensus, there are dissenting voices. Based on Henrik Svensmark's research at the Danish National Space Center, this book outlines a brilliant and daring new theory that has already provoked fresh thinking on global warming. As prize-winning science writer Nigel Calder and Svensmark himself explain, an interplay of the sun and cosmic rays - sub-atomic particles from exploded stars - seem to have more effect on the climate than man-made carbon dioxide. For anyone interested in the real science behind our climate, this book is a must-read.

Mountain Biking Arizona Trail Guide: Fat Tire Tales & Trails

Mountain Biking Arizona Trail Guide: Fat Tire Tales & Trails
by Cosmic Ray (Author), Cosmic Ray (Editor), Cosmic Ray (Editor)

The most well know and well loved mountain bike trail guide to the best summer and winter fat tire fun in Arizona. Cartoony, down to earth maps are adapted from U.S.G.S. topos and U.S. Forest Service charts, yet are friendly and easy to use. Maps are to scale and oriented north. Each humorous route description includes distance, time, effort and skill required, best season to ride, skill level required contour profile and "fear factor". There is a turn by turn mileage log when applicable. A "preferred trail" icon is used to indicate a particularly great ride in a given are for those on a limited time schedule. Rides are included for all levels of ability, but emphasis is given to the intermediate/advanced rider. A few severe/extreme rides are included for those on the lunatic fringe. Each...

© 2014