Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Magnetars, the most magnetic stars known, more common than previously thought


Observations of explosions from an ultra-powerful magnetic neutron star playing hide-and-seek with astronomers suggest that these exotic objects called magnetars — capable of stripping a credit card clean 100,000 miles away — are far more common than previously thought.

Scientists from the United States and Canada present this result today at the meeting of the American Astronomical Society in Atlanta . The work is based on observations with the European Space Agency’s XMM-Newton observatory and NASA’s Rossi X-ray Timing Explorer.

"We only know of about ten magnetars in the Milky Way galaxy," said the investigation’s leader, Dr. Peter Woods of NASA’s Marshall Space Flight Center in Huntsville , Ala. , based at the National Space Science and Technology in Huntsville . "If the antics of the magnetar we are studying now are typical, turning on and off but never getting exceptionally bright, then there very well could be hundreds more out there."

Wood’s colleagues are: Dr. Vicky Kaspi and Mr. Fotis Gavriil of McGill University in Montreal; Dr. Christopher Thompson of the Canadian Institute for Theoretical Astrophysics; Drs. Herman Marshall, Deepto Chakrabarty and Kathy Flanagan at the Massachusetts Institute of Technology; and Drs. Jeremy Heyl and Lars Hernquist at the Harvard-Smithsonian Center for Astrophysics.

The source in question is a magnetar "candidate" named 1E 2259+586 in the constellation Cassiopeia, approximately 18,000 light years from Earth. A magnetar is a special neutron star. A neutron star is a compact sphere approximately 15 kilometers (10 miles) in diameter, the core remains of a collapsed star roughly ten times more massive than the Sun. Magnetars, for reasons poorly understood, have magnetic fields a thousand times stronger than ordinary neutron stars, measuring 10 14 to 10 15 Gauss (or about a hundred-trillion refrigerator magnets; the Sun’s magnetic field is about 5 Gauss.)

Not all scientists are convinced that neutron stars can be so magnetic. As such, magnetar candidates are often referred to in the scientific literature as either Soft Gamma-ray Repeaters (SRGs) or Anomalous X-ray Pulsars (AXPs), depending on their bursting characteristics. Members of this observation team helped established the connection between SRGs and AXPs in 2002. The source 1E 2259 is sometimes called an AXP.

For all their power, magnetars are not always majestic beacons. The opportunity to study them comes when they erupt for hours to months, without warning, emitting visible light and other wavelengths before growing dim once more. Magnetar 1E 2259 suddenly began bursting in June 2002. Scientists collected data on over 80 bursts recorded within a 4-hour window. No other bursts have been detected since.

These same changes in emissions happened 12 years ago and remained a mystery until this study. "Knowing what we know now, we realize that the earlier burst activity was too dim to observe," said Woods.

The cumulative properties of the outburst in 1E 2259+586 led the team to make several conclusions: First, the star suffered some major event lasting several days with two distinct components, one on the surface of the star (perhaps a fracture in the crust) and the other beneath the surface.

According to Kaspi, "The changes in persistent emission properties suggest that the star underwent a plastic deformation of the crust that simultaneously impacted the superfluid interior and the magnetosphere." (A neutron star’s interior is thought to be a superfluid of neutrons. The magnetosphere refers to the region in which the neutron star’s magnetic field controls the behavior of the charged particles.)

The emission after the bursting was similar to that of an SGR, further blurring the distinction between these two exotic species, Kaspi said. Also, from the changes in emission, the scientists could infer previous burst active episodes from this and other magnetar candidates.

"This sort of behavior could be happening all the time in other sources like it throughout the Galaxy and we would never know it because our gamma-ray ’eyes’ are not sensitive enough," said Woods.

Thus, the non-detection of such outbursts by telescopes scanning the entire sky for X-ray and gamma-ray sources suggests that the number of magnetar candidates in our Galaxy is larger than previously thought but that they are in a prolonged dim phase. The team plans to calculate this number. Helping them will be the NASA Swift Gamma-Ray Burst Explorer, scheduled for launch in mid-2004. Swift will be about 20 times more sensitive to magnetar bursts than anything that has flown before. "If there is a big population of these objects out there, Swift should find them," Woods said.

"Magnetars are not just the most magnetic stars known but they are stars not powered by a conventional mechanism such as nuclear fusion, rotation or accretion," Kaspi said. "Magnetars represent a new way for a star to shine, which makes this a fascinating field."

ESA’s XMM-Newton was launched in December 1999. NASA helped fund mission development and supports guest observer time. The Rossi Explorer was launched in December 1995. NASA’s Goddard Space Flight Center in Greenbelt , Md. , manages the day-to-day operation of the satellite and maintains its data archive.

Peter Woods joins the National Space Science and Technology Center through the Universities Space Research Association. Fotis Gavriil is a graduate student in the Physics Department of McGill University.

Steve Roy | MSFC
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>