- 3004 - MAGNETARS - spinning neutron stars? When stars grow too big they collapse their atoms and blow up as a supernova. The collapsed center core left behind are the electrons crushed into the protons leaving only neutrons to form the neutron star. It is only 12 miles in diameter. Neutron stars can have some bizarre behaviors renaming them magnetars and pulsars.
-------------------- 3004 - MAGNETARS - spinning neutron stars?
- If a magnetar flew past Earth within 100,000 miles, the intense magnetic field of the exotic object would destroy the data on every credit card on the planet. The magnetar, “1E 1048.1-5937“, is located 9,000 light-years away in the constellation Carina. The original star, out of which the magnetar formed, had a mass 30 to 40 times that of the Sun.
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- Such a massive beginning would help explain the difference between magnetars and their close cousins, pulsars. Pulsars are stellar corpses that serve as the radio lighthouses of the galaxy. Spinning around several times a second, they flash the galaxy with a beam of radio waves.
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- Magnetars are similar, but they flash X-rays, and at a slower rate once every 10 seconds. They also occasionally let out a burst of gamma rays.
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- There are about 1,500 known pulsars, but less than a dozen firmly identified magnetars. What makes magnetars special is their magnetic field, which is thousands of times stronger than that of normal pulsars and billions of times stronger than that of any magnet on Earth.
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- These magnetic fields can be measured by observing how quickly the spin of the magnetar slows down. A rotating magnet gives off energy, and the greater the magnetic field, the faster the energy loss. Magnetars exhibit rapid deceleration, which implies a huge magnetic field. After 10,000 years a magnetar will slow down enough to turn off its X-ray flash.
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- Magnetars and pulsars belong to a class of objects called neutron stars, which are big balls of tightly packed neutrons no larger than a big city. When stars above about eight solar masses run out of fuel to burn, they explode in what is called a “supernova“. What remains can collapses into a neutron star.
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- To have such large magnetic fields, magnetars are thought to originate from the supernova of very massive stars. It takes a very massive star, some 30 to 40 solar masses. This progenitor star lives 5-6 million years before it explodes , creating the magnetar in its ashes. Massive stars die young. Our middle-ages Sun, by comparison, is about 4.6 billion years old.
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- Astronomers used to think that really massive stars formed blackholes when they died. But in the past few years they have realized that some of these stars could form pulsars, because they go on a rapid weight-loss program before they explode as supernovae. At the very end of its life, the star likely lost 90 percent of its mass, which would make it skinny enough to become a neutron star, as opposed to a blackhole.
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- In our galaxy there are only about 10 neutron stars from a massive enough progenitor and at the right age to be magnetars right now. There could be many more "dead" magnetars in the galaxy.
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- Observations of "starquakes" have allowed scientists to estimate the thickness of a neutron star's crust for the first time. Neutron stars are very dense objects that mark the endpoints of the lives of some stars.
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- Using a technique similar to seismology here on Earth, researchers estimated that the crust of a highly magnetic neutron star, a "magnetar," is nearly 1 mile thick and made of material so tightly packed that a teaspoonful of the stuff would weigh about 10 million tons on Earth.
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A neutron star forms when an ancient star several times more massive than our Sun runs through its entire stock of nuclear fuel. The star collapses under the weight of its own gravity and explodes in a cataclysmic event called a supernova.
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- The blast ejects most of the star's mass into space, leaving behind a dense, rapidly spinning core about the size of a small city and roughly 1.4 times more massive than our Sun.
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- Magnetar's are neutron stars whose magnetic fields are thousands of times stronger than their pulsars. Astronomers have detected only about a dozen such stars. A magnetar's magnetic field is equivalent to about a hundred trillion refrigerator magnets and so strong that it could slow a steel locomotive from as far away as the Moon.
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- The flash resulted from a violent explosion called a "hyperflare," which occurs when a magnetar's magnetic field lines become so twisted with one another that they snap. Like a tightly wound rubber band that finally breaks, the snapping released tremendous amounts of energy, triggering a "starquake" that buckled the star's crust.
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- The researchers calculated the thickness of the magnetar's crust by comparing the frequencies of energy waves traveling around the star against those passing through its interior. If an even larger starquake could be observed, it could provide a glimpse into what kind matter makes up a neutron star's core.
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- The interior of neutron stars has been a source of great mystery and speculation for scientists. The pressure and density inside a neutron star core is thought to be so great that it could harbor exotic particles not made apparent since the moment of the Big Bang.
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- One possibility is that the stars' interiors are home to unbound versions of the building blocks of protons and neutrons, called quarks. Even the most powerful particle accelerators on Earth can't muster up the energies needed to reveal free quarks.
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- Astronomers have discovered two neutron stars orbiting each other once every 2.4 hours and spiraling inward toward an eventual dramatic collision. The finding suggest such intense events are far more common than was thought. Astronomers could detect elusive "gravitational waves," which should be spawned in the final seconds prior to the mighty mergers.
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- A neutron star is already stellar corpse. It is formed when an aged star explodes and as much material as what's in our Sun collapses into a region the size of a city. A teaspoonful, brought to Earth, would weigh a billion tons or so. Neutron stars are stuffed almost entirely with neutrons, subatomic particles that can huddle extremely close together.
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- Only six neutron-star pairs, called binary systems, are now known. Previous studies of other pairs have shown that these exotic dance teams spiral toward each other and must eventually crash and unite, possibly becoming a black hole. Einstein theorized that space-warping gravitational waves caused by two accelerated masses in orbit are the reason for this orbital decay.
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- As Einstein's theory has it, any pair of neutron stars should begin a detectable death chirp moments before they merge. One minute before the stars merge, their orbit has shrunk to a size of only a few hundred miles and the two neutron stars move around each other some 30 times each second, producing strong gravitational waves with that same frequency (30 hertz).
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- In the last minute before the merger, the orbital frequency increases rapidly, from 30 to 1,000 times per second; the strength of the gravitational wave emission increases simultaneously. When the waves reach Earth, their effect would be to displace the oceans by an amount roughly 10 times the diameter of an atomic nucleus.
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- There are several projects around the world designed to detect these otherwise unnoticed waves. Among the most prominent is the Laser Interferometer Gravitational Wave Observatory (LIGO).
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- Gravitational waves are said to be similar to light waves. Both propagate through space at different frequencies, radiating outward like ripples on a pond. But gravitational radiation is much weaker than electromagnetic radiation, which includes light, radio waves and X-rays. This is because the fundamental force of gravity is weaker than the fundamental electromagnetic force.
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- The Sun is a middle-aged star about 8 light-minutes from us. Its tantrums, though cosmically pitiful compared to the magnetar explosion, routinely squish Earth's protective magnetic field and alter our atmosphere, lighting up the night sky with colorful lights called “aurora“.
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- Solar storms also alter the shape of Earth's ionosphere, a region of the atmosphere 50 miles up where gas is so thin that electrons can be stripped from atoms and molecules and roam free for short periods. Fluctuations in solar radiation cause the ionosphere to expand and contract.
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- A neutron star is the remnant of a star that was once several times more massive than the Sun. When their nuclear fuel is depleted, they explode as a supernova. The remaining dense core is slightly more massive than the Sun but has a diameter typically no more than 12 miles.
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- Millions of neutron stars fill the Milky Way galaxy. A dozen or so are ultra-magnetic neutron stars, or magnetars. The magnetic field around one is about 1,000 trillion gauss, strong enough to strip information from a credit card at a distance halfway to the Moon.
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- A relatively small, dense object racing across the sky and heading our way at more than 100 times the speed of a Concorde jet has been identified as our solar system's closest known neutron star.
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- The compact remains of an ancient explosion, less than 12 miles in diameter but 10 trillion times denser than steel, the neutron star zips along at roughly 240,000 miles per hour. Most neutron stars are found in paired or binary star systems but this runaway object has broken free of its larger companion, giving astronomers a rare treat.
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- The object, first spotted in 1992, was confirmed to be a neutron star in 1996. But only now has its distance from Earth been determined, using data provided by the Hubble Space Telescope. The object, also described as the corpse of a star, currently is about 200 light-years away. It is due to pass by Earth in about 300,000 years, but will safely miss by about 170 light-years.
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- When massive stars go supernova they produce a magnificent nebula. But if the star is not massive enough to produce a blackhole, it usually leaves behind a neutron star.
A neutron star crams as much mass as our sun into a sphere just 10 miles across. Squeezing out the empty space that makes up most of the suns volume, neutron stars leave naked atomic nuclei crammed together.
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- This dense star rotates has an intense magnetic field and a thin crust of iron nuclei packed into a crystalline lattice. A neutron star has an extra strong magnetic field. At about 44 trillion gauss, the magnetic field is 1,000 times stronger than that of an ordinary neutron star. By comparison, the Earth's magnetic field is a tame 0.6 gauss, and a refrigerator magnet's, a feeble 100 gauss.
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- The most a human being can normally expect to be exposed to in his life is about 100,000 gauss from a magnetic resonance imager. A field of 1 billion gauss would turn you into magnetized mush.
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- Since the stars magnetic field drags on it, it slows it each rotation. The losses are almost imperceptible, about 1 part in 100 billion. But that represents a lot of energy since it's braking such a compact yet massive object. In the span of about 10,000 years it slows down to become an X-ray Pulsar. Only six are known to date.
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- Under the magnetar theory, one way that energy is released is when the diamond-like crust suddenly cracks, shifting and pumping energy into the ionized gases trapped around the magnetar. The result of the “star quake” arrives at Earth as brilliant gamma-ray flares. On Aug. 27, 1998, such an outburst ionized as much of the Earth's outer atmosphere as the sun would at high noon.
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- We in California know that earthquakes don't last for a fraction of a second. The slowing of the star is caused not by the magnetic field but by its generating a wind that departs at close to the speed of light. This is evidence for a new state of matter heavier than any previously known, equivalent in density to stuffing all of Earth into an auditorium.
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- The research involved two stars expected to be neutron stars, remnants of exploded stars that are composed primarily of neutrons and would be very dense. Each of the stars in the two new studies may contain exotic particles called quarks.
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- Quarks are thought to be fundamental building blocks of matter. But they have never been observed alone, instead always existing together as the components of other matter. If they were liberated inside a star, they could theoretically be compressed into a smaller sphere.
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- Massive, dying stars vibrate like giant speakers and emit an audible hum before exploding in one of nature's most spectacular blasts. Sound waves, not ghostly particles called neutrinos, deal the final blow to stars before they become supernovas.
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- Supernovas are powerful stellar blasts that briefly outshine entire galaxies and radiate more energy than our Sun will in its entire lifetime. Only a star that is between 10 to 25 times more massive than our Sun can become a supernova. After it has burned for 10 to 20 million years or so, the star runs out of fuel and develops a dense iron core about the size of Earth.
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- The iron core grows until its density becomes so great that it collapses under its own weight. The core contracts, but then almost immediately springs back again. This sudden rebounding action generates a shockwave that speeds outward. It is this departing shockwave that triggers the supernova explosion.
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- The problem is that in even the best computer simulations, the shock wave isn't powerful enough on its own to break through the dense layers of superheated gas that envelops the core. In the models, the shock wave stalls as if muffled by a blanket and the supernova explosion never occurs.
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- In the late 1980s, scientists began experimenting with the idea that ghostly subatomic particles known as neutrinos might provide the extra power boost needed to complete the blast. Neutrinos have no charge and are nearly massless.
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- They are produced in vast quantities during the final stages of a massive star's life and stream out of the star's inner core. It was thought that these escaping particles might carry enough energy out of the core to the star's outer layers to complete the explosion. But even when scientists incorporated the outflow of neutrinos into their computer simulations, it still wasn't enough to produce consistent supernovas.
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- The team's model shows that after about half a second, the collapsing inner core begins to vibrate. After about 700 milliseconds, the vibrations become so energetic that they create sound waves with audible frequencies in the range of 200 to 400 hertz, or around middle C.
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- Instead of neutrino's heating up the material behind the shock, we had acoustic power doing it. The material on the inside is oscillating like a very, very strong speaker and sending out energy via sound. The sound waves replace neutrinos as energy carriers.
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- The sound waves propagate out through the material and heat it up. It acts in a way similar to the way neutrinos would act but with more efficiency. That is the way supernovas happen. Trust me.
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- 1383 - Magnetars - Lethal Neutron Stars Neutron Stars can generate intense magnetic fields creating star quakes that release lethal Gamma Ray Bursts.
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- 1223 - Where Do Big Stars Go When They Die? Big stars have short lives and dramatic deaths. This review highlights the bigger supernovae explosions that create Gamma Ray Bursts, Magnetars, and Pulsars. It refers to a small satellite student project that hopes to contribute to our understanding of these cosmic wonders.
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- 1159 - What Are Magnetars? After a supernova explosion of a massive star the remaining core can collapse into a Neutron Star, or a Blackhole, depending on how massive the core is that remains. In certain situations the core could be a rapidly spinning , intensely magnetic Neutron Star, called a Magnetar. Neutron Stars are made of neutrons, not charged particles. Spinning neutrons would not create a magnetic field. Nothing escapes a Blackhole. So, how can Neutron Stars and Blackholes create the enormous magnetic fields?
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January 27, 2021 MAGNETARS - spinning neutron stars? 3004
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