 |
|
Neutron stars can be more massive, while black holes are more rare, Arecibo Observatory finds
January 15, 2008AUSTIN, Texas - Neutron stars and black holes aren't all they've been thought to be.
In fact, neutron stars can be considerably more massive than previously believed, and it is more difficult to form black holes, according to new research developed by using the Arecibo Observatory in Arecibo, Puerto Rico. Paulo Freire, an astronomer from the observatory, will present his research at the American Astronomical Society national meeting in Austin on Jan. 11.
The Arecibo Observatory is managed by Cornell University for the National Science Foundation.
In the cosmic continuum of dead, remnant stars, the Arecibo astronomers have increased the mass limit for when neutron stars turn into black holes.
"The matter at the center of a neutron star is highly incompressible. Our new measurements of the mass of neutron stars will help nuclear physicists understand the properties of super-dense matter," said Freire. "It also means that to form a black hole, more mass is needed than previously thought. Thus, in our universe, black holes might be more rare and neutron stars slightly more abundant."
When the cores of massive stars run out of nuclear fuel, their enormous gravitation then causes their collapse then becomes a supernova. The core, typically with a mass 1.4 times larger than that of the sun is compressed into a neutron star. These extreme objects have a radius about 10 to 16 kilometers and a density on the order of a billion tons per cubic centimeter. Freire says that a neutron star is like one single, giant atomic nucleus with about 460,000 times the mass of the Earth.
Astronomers had thought the neutron stars needed a maximum mass between 1.6 and 2.5 suns in order to collapse and become black holes. However, this new research shows that neutron stars remain neutron stars between the mass of 1.9 and up to possibly 2.7 suns.
"The matter at the center of the neutron stars is the densest in the universe. It is one to two orders of magnitude denser than matter in the atomic nucleus. It is so dense we don't know what it is made out of," said Freire. "For that reason, we have at present no idea of how large or how massive neutron stars can be."
From June 2001 to March 2007, Freire used Arecibo's "L-wide" receiver (sensitive to radio frequencies from 1100 to 1700 MHz) and the Wide-Band Arecibo Pulsar Processors - a very fast spectrometer on the Arecibo telescope - to examine a binary pulsar called M5 B, in the globular cluster M5, which is located in the constellation Serpens. Like a lighthouse emits light, a pulsar is a strongly magnetized neutron star that emits large amounts of electromagnetic radiation, usually from its magnetic pole. As in the case of a lighthouse, distant observers perceive a sequence of pulsations, which are caused by the rotation of the pulsar. In the case of M5 B, these radio pulsations arrive at the Earth every 7.95 milliseconds.
These radio pulsations were scanned by the wide-band spectrometers once every 64 microseconds for 256 spectral channels, and then recorded to a computer disk, with accurate timing information. The precise arrival time of the pulses were then used by the astronomers to accurately measure the orbital motion of M5 B about its companion. This allowed the astronomers to estimate the mass (1.9 solar masses) of the pulsar.
Cornell University Communications
In the cosmic continuum of dead, remnant stars, the Arecibo astronomers have increased the mass limit for when neutron stars turn into black holes.
"The matter at the center of a neutron star is highly incompressible. Our new measurements of the mass of neutron stars will help nuclear physicists understand the properties of super-dense matter," said Freire. "It also means that to form a black hole, more mass is needed than previously thought. Thus, in our universe, black holes might be more rare and neutron stars slightly more abundant."
When the cores of massive stars run out of nuclear fuel, their enormous gravitation then causes their collapse then becomes a supernova. The core, typically with a mass 1.4 times larger than that of the sun is compressed into a neutron star. These extreme objects have a radius about 10 to 16 kilometers and a density on the order of a billion tons per cubic centimeter. Freire says that a neutron star is like one single, giant atomic nucleus with about 460,000 times the mass of the Earth.
Astronomers had thought the neutron stars needed a maximum mass between 1.6 and 2.5 suns in order to collapse and become black holes. However, this new research shows that neutron stars remain neutron stars between the mass of 1.9 and up to possibly 2.7 suns.
"The matter at the center of the neutron stars is the densest in the universe. It is one to two orders of magnitude denser than matter in the atomic nucleus. It is so dense we don't know what it is made out of," said Freire. "For that reason, we have at present no idea of how large or how massive neutron stars can be."
From June 2001 to March 2007, Freire used Arecibo's "L-wide" receiver (sensitive to radio frequencies from 1100 to 1700 MHz) and the Wide-Band Arecibo Pulsar Processors - a very fast spectrometer on the Arecibo telescope - to examine a binary pulsar called M5 B, in the globular cluster M5, which is located in the constellation Serpens. Like a lighthouse emits light, a pulsar is a strongly magnetized neutron star that emits large amounts of electromagnetic radiation, usually from its magnetic pole. As in the case of a lighthouse, distant observers perceive a sequence of pulsations, which are caused by the rotation of the pulsar. In the case of M5 B, these radio pulsations arrive at the Earth every 7.95 milliseconds.
These radio pulsations were scanned by the wide-band spectrometers once every 64 microseconds for 256 spectral channels, and then recorded to a computer disk, with accurate timing information. The precise arrival time of the pulses were then used by the astronomers to accurately measure the orbital motion of M5 B about its companion. This allowed the astronomers to estimate the mass (1.9 solar masses) of the pulsar.
Cornell University Communications
Neutron Stars Current Events and Neutron Stars News RSSCarbon atmosphere discovered on neutron star
Evidence for a thin veil of carbon has been found on the neutron star in the Cassiopeia A supernova remnant. This discovery, made with NASA's Chandra X-ray Observatory, resolves a ten-year mystery surrounding this object.
Fermi telescope caps its first year with a glimpse of space-time
During its first year of operations, NASA's Fermi Gamma Ray Space Telescope mapped the extreme sky with unprecedented resolution and sensitivity.
Gamma-ray photon race ends in dead heat; Einstein wins this round
Racing across the universe for the last 7.3 billion years, two gamma-ray photons arrived at NASA's orbiting Fermi Gamma-ray Space Telescope within nine-tenths of a second of one another.
New vista of Milky Way center unveiled
A dramatic new vista of the center of the Milky Way galaxy from NASA's Chandra X-ray Observatory exposes new levels of the complexity and intrigue in the Galactic center.
Theoretical nuclear physics in China
In recent years several Large-Scale Scientific Facilities (LSSF) for nuclear, hadronic, and particle physics have been upgraded and constructed in China.
Sophisticated telescope camera debuts with peek at nest of black holes
Less than two months after they inaugurated the world's largest telescope, University of Florida astronomers have used one of the world's most advanced telescopic instruments to gather images of the heavens.
Fermi Large Area Telescope reveals pulsing gamma-ray sources
Scientists at the Naval Research Laboratory (NRL) Space Science Division and a team of international researchers have positively identified cosmic sources of gamma-ray emissions through the discovery of 16 pulsating neutron stars.
Goddard-Led GEMS Mission to Explore the Polarized Universe
An exciting new astrophysics mission led by NASA's Goddard Space Flight Center in Greenbelt, Md., will provide a revolutionary window into the universe. Named the Gravity and Extreme Magnetism Small Explorer (GEMS), the satellite will be the first to systematically measure the polarization of cosmic X-ray sources.
Quantum goes massive
An astrophysics experiment in America has demonstrated how fundamental research in one subject area can have a profound effect on work in another as the instruments used for the Laser Interferometer Gravitational-Wave Observatory (LIGO) pave the way for quantum experiments on a macroscopic scale.
European Satellites Probe a New Magnetar
On Aug. 22, 2008, NASA's Swift satellite reported multiple blasts of radiation from a rare object known as a soft gamma repeater, or SGR.
More Neutron Stars Current Events and Neutron Stars News Articles
 |
Neutron Stars and Pulsars (Astrophysics and Space Science Library) by Werner Becker (Author), Werner Becker (Editor) Neutron stars are the most compact astronomical objects in the universe which are accessible by direct observation. Studying neutron stars means studying physics in regimes unattainable in any terrestrial laboratory. Understanding their observed complex phenomena requires a wide range of scientific disciplines, including the nuclear and condensed matter physics of very dense matter in neutron star interiors, plasma physics and quantum electrodynamics of magnetospheres, and the relativistic magneto-hydrodynamics of electron-positron pulsar winds interacting with some ambient medium. Not to mention the test bed neutron stars provide for general relativity theories, and their importance as potential sources of gravitational waves. It is this variety of disciplines which, among... |
 |
Neutron Stars 1: Equation of State and Structure (Astrophysics and Space Science Library) (v. 1) by P. Haensel (Author), A.Y. Potekhin (Author), D.G. Yakovlev (Author) The book gives an extended review of theoretical and observational aspects of neutron star physics. With masses comparable to that of the Sun and radii of about ten kilometres, neutron stars are the densest stars in the Universe. This book describes all layers of neutron stars, from the surface to the core, with the emphasis on their structure and equation of state. Theories of dense matter are reviewed, and used to construct neutron star models. Hypothetical strange quark stars and possible exotic phases in neutron star cores are also discussed. Also covered are the effects of strong magnetic fields in neutron star envelopes and a comparison on neutron star models with observations. |
 |
Black Holes, White Dwarfs and Neutron Stars: The Physics of Compact Objects by Stuart L. Shapiro (Author), Saul A. Teukolsky (Author) Black holes, White Dwarfs, and Neutron Stars The physics of Compact Objects Compact objects—black holes, white dwarfs, and neutron stars—are fundamental constituents of the physical universe. They are born when normal stars die. This book is a product of the recent explosion of scientific activity centering on these objects. This self-contained work is a rigorous, yet understandable, references on the latest theoretical and observational developments. It is at once an outstanding text for graduate and advanced undergraduate students in physics, and a practical self-study guide for scientists in other disciplines and scientifically-oriented laypersons. No prior knowledge of astrophysics or relativity theory is required. Compact objects provide unique cosmic laboratories for testing... |
 |
Black Hole Star/Tales from the Blues Cocoons by Neutrons |
 |
Jimmy Neutron: Boy Genius by THQ Jimmy Neutron: Boy Genius tells the story of a 10-year-old boy who, along with his robot dog Goddard, battles evil, rescues his parents from aliens, saves Earth, and still makes it home in time for supper. The game features tons of techno gadgets, including a laser gun, shrink ray, asthma spray, and missiles. The game features multiplayer character abilities for Jimmy, Goddard, Carl, Nick, Dad, Cindy, and Ultra Lord. Areas include Retroville, a meteor storm, the Yokian moon, and a Yokian chase through space. |
 |
Neutron Star William Orbit (Primary Contributor) |
 |
Heavier Than A Neutron Star Dormir (Primary Contributor) |
 |
Neutron Star by Larry Niven (Author) Come to Larry Niven's Universe and meet all the natives: Thrints, Bandersnatchi, Puppeteers -- and a host of other wonderfully created characters. Visit Lookitthat, Down, and Jinx -- indeed, an entire galaxy of planets found only in these stories that trace man's expansion and colonization throughout Known Space. A spectacular cycle of the future . . . a 10,000-year history of man on Earth and in space! |
 |
Death of a Neutron Star (Star Trek Voyager, No 17) by Eric Kotani (Author) An alien scientist asks to join Captain Kathryn Janeway and her crew in the investigation of an unprecedented scientific find. Soon U.S.S. Voyager® is embroiled in a battle of wills among several alien races -- each intent on manipulating the discovery toward its own end and decimating whole worlds in the process. Janeway must stop a quest for knowledge from turning into a plot for destruction! |
![Journeys to the Edge of Creation Set [VHS]](http://ecx.images-amazon.com/images/I/51bF0UeWMnL._SL160_.jpg) |
Journeys to the Edge of Creation Set [VHS] Also With: Moody Video (Producer) The cosmos! A vast frontier of seemingly infinite wonder and size. Now you can see it unfold before your very eyes. Marvel at the magnificence. Thrill to the diversity as you soar effortlessly among the planets. Through blazing, brilliant galaxies. Beyond quasars, nebulae, exploding stars and mysterious black holes. Join scientific experts in this timeless quest for discovery, enhanced by amazing tools of astronomy that draw the deepest regions of space into clearer focus than at any time in history. |
| © 2009 BrightSurf.com |