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Magnetic Star Reveals Its Hidden Power

August 14, 2013 Leave a comment

Artist's impression. Credit: ESA/ATG Medialab

Artist’s impression. Credit: ESA/ATG Medialab

A team of astronomers including two researchers from UCL’s Mullard Space Science Laboratory has made the first ever measurement of the magnetic field at a specific spot on the surface of a magnetar. Magnetars are a type of neutron star, the dense and compact core of a giant star which has blasted away its outer layers in a supernova explosion.

Magnetars have among the strongest magnetic fields in the Universe. Until now, only their large scale magnetic field had been measured. However, using a new technique and observations of a magnetar in X-rays, the astronomers have now revealed a strong, localised surface magnetic field on one.

Magnetars are very puzzling neutron stars. Astronomers discovered them through their unusual behaviour when observed in X-ray wavelengths, including sudden outbursts of radiation and occasional giant flares. These peculiar features of magnetars are caused by the evolution, dissipation and decay of their super-strong magnetic fields, which are hundreds or thousands of times more intense than those of the more common type of neutron stars, the radio pulsars.

Full Story: http://www.ucl.ac.uk/maps-faculty/maps-news-publication/maps1323
Also: http://www.esa.int/Our_Activities/Space_Science/Mysterious_magnetar_boasts_one_of_strongest_magnetic_fields_in_Universe

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The Largest Magnetic Fields In The Universe


An ultra-dense (“hypermassive”) neutron star is formed when two neutron stars in a binary system finally merge. Its short life ends with the catastrophic collapse to a black hole, possibly powering a short gamma-ray burst, one of the brightest explosions observed in the universe. Short gamma-ray bursts as observed with satellites like XMM Newton, Fermi or Swift release within a second the same amount of energy as our Galaxy in one year. It has been speculated for a long time that enormous magnetic field strengths, possibly higher than what has been observed in any known astrophysical system, are a key ingredient in explaining such emission. Scientists at the Max Planck Institute for Gravitational Physics (Albert Einstein Institute/AEI) have now succeeded in simulating a mechanism which could produce such strong magnetic fields (stronger than ten or hundred million billion times the Earth’s magnetic field)* prior to the collapse to a black hole.

* Strength inserted from elsewhere in the story.

Full Story: http://www.aei.mpg.de/303590/Die_staerksten_Magnetfelder_im_Universum

Earth’s Gold Came From Colliding Dead Stars


Artist's conception. Credit: Dana Berry, SkyWorks Digital, Inc.

Artist’s conception. Credit: Dana Berry, SkyWorks Digital, Inc.

We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it’s also rare in the universe. Unlike elements like carbon or iron, it cannot be created within a star. Instead, it must be born in a more cataclysmic event – like one that occurred last month known as a short gamma-ray burst (GRB). Observations of this GRB provide evidence that it resulted from the collision of two neutron stars – the dead cores of stars that previously exploded as supernovae. Moreover, a unique glow that persisted for days at the GRB location potentially signifies the creation of substantial amounts of heavy elements – including gold.

“We estimate that the amount of gold produced and ejected during the merger of the two neutron stars may be as large as 10 moon masses – quite a lot of bling!” says lead author Edo Berger of the Harvard-Smithsonian Center for Astrophysics (CfA).

Full Story: http://www.cfa.harvard.edu/news/2013/pr201319.html

Blitzars: Fast Radio Bursts From Supramassive Rotating Neutron Stars


Image Credit: Nasa

Image Credit: Nasa

Radio telescopes have picked up some bright radio flashes that appear for only a brief moment on the sky and do not repeat (Thornton et al. 2013, Science). So, what causes these unusual radio signals? We suggest in a recent paper (Falcke & Rezzolla 2013, ArXiv.org) that this could be the final farewell greetings of a supramassive rotating neutron star (SURON) collapsing into a black hole and shedding its magnetic field.

Full Story: http://www.astro.ru.nl/~falcke/PR/blitzar/

The Violent Birth Of Neutron Stars


A team of researchers at the Max Planck Institute for Astrophysics conducted the most expensive and most elaborate computer simulations so far to study the formation of neutron stars at the center of collapsing stars with unprecedented accuracy. These worldwide first three-dimensional models with a detailed treatment of all important physical effects confirm that extremely violent, hugely asymmetric sloshing and spiral motions occur when the stellar matter falls towards the center. The results of the simulations thus lend support to basic perceptions of the dynamical processes that are involved when a star explodes as supernova.

Stars with more than eight to ten times the mass of our Sun end their lives in a gigantic explosion, in which the stellar gas is expelled into the surrounding space with enormous power. Such supernovae belong to the most energetic and brightest phenomena in the universe and can outshine a whole galaxy for weeks. They are the cosmic origin of chemical elements like carbon, oxygen, silicon, and iron, of which the Earth and our bodies are made of, and which are bred in massive stars over millions of years or freshly fused in the stellar explosion.

Supernovae are also the birth places of neutron stars, those extraordinarily exotic, compact stellar remnants, in which about 1.5 times the mass of our Sun is compressed to a sphere with the diameter of Munich. This happens within fractions of a second when the stellar core implodes due to the strong gravity of its own mass. The catastrophic collapse is stopped only when the density of atomic nuclei – gargantuan 300 million tons in a sugar cube – is exceeded.

Full Story: http://www.mpa-garching.mpg.de/mpa/institute/news_archives/news1306_ddd/news1306_ddd-en.html

The University Of Alicante Finds The First Evidence Of A New Phase In Neutron Stars


A study led by the University of Alicante, in which in the National Research Council (CSIC) has participated, has detected what may be the first observational evidence of existence of a new exotic phase of matter in the inner crust of neutron stars (pulsars).

The latest issue of Nature Physics shows the results of a research project that addresses one of the unknowns in the field of X-ray pulsars, the existence of a limit higher than 12 seconds in the rotation periods of isolated neutron stars. This limit is actually due to the existence of new exotic phases of matter. Pulsars are neutron stars (ultracompact and strongly magnetized stars) in rotation, which emit electromagnetic radiation with amazing precision in their periodicity.

As José A. Pons says, lecturer at the University of Alicante’s Relativistic Astrophysics Group and Director of the Department of Applied Physics, who led the work: “This may be the first observational evidence of existence of the phase of nuclear ‘pasta’ inside neutron stars, which may allow that future missions of X-ray observatories can be used to define aspects of how nuclear interaction works, which is not yet entirely clear”.

Nuclear Pasta, named for its resemblance to the Italian pasta, occurs when the combination of nuclear and electromagnetic forces, at densities close to the atomic nuclei, favours the ordering of the nucleons (protons and neutrons) in non-spherical shapes , as sheets or filaments (lasagna or spaghetti).

Full Story: http://www.alphagalileo.org/ViewItem.aspx?ItemId=132027&CultureCode=en

NASA’s Swift Reveals New Phenomenon In A Neutron Star


Credit: ESA/XMM-Newton/M. Sasaki et al

Credit: ESA/XMM-Newton/M. Sasaki et al

Astronomers using NASA’s Swift X-ray Telescope have observed a spinning neutron star suddenly slowing down, yielding clues they can use to understand these extremely dense objects.

A neutron star is the crushed core of a massive star that ran out of fuel, collapsed under its own weight, and exploded as a supernova. A neutron star can spin as fast as 43,000 times per minute and boast a magnetic field a trillion times stronger than Earth’s. Matter within a neutron star is so dense a teaspoonful would weigh about a billion tons on Earth.

This neutron star, 1E 2259+586, is located about 10,000 light-years away toward the constellation Cassiopeia. It is one of about two dozen neutron stars called magnetars, which have very powerful magnetic fields and occasionally produce high-energy explosions or pulses.

Observations of X-ray pulses from 1E 2259+586 from July 2011 through mid-April 2012 indicated the magnetar’s rotation was gradually slowing from once every seven seconds, or about eight revolutions per minute. On April 28, 2012, data showed the spin rate had decreased abruptly, by 2.2 millionths of a second, and the magnetar was spinning down at a faster rate.

“Astronomers have witnessed hundreds of events, called glitches, associated with sudden increases in the spin of neutron stars, but this sudden spin-down caught us off guard,” said Victoria Kaspi, a professor of physics at McGill University in Montreal. She leads a team that uses Swift to monitor magnetars routinely.

Full Story: http://www.nasa.gov/mission_pages/swift/bursts/new-phenom.html