Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

07.01.2004


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:
http://www1.msfc.nasa.gov/NEWSROOM/NSSTC/news/releases/2004/N04-001.html

More articles from Physics and Astronomy:

nachricht Artificial Intelligence Helps in the Discovery of New Materials
21.09.2016 | Universität Basel

nachricht Magnetic polaron imaged for the first time
19.09.2016 | Aalto University

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: OLED microdisplays in data glasses for improved human-machine interaction

The Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP has been developing various applications for OLED microdisplays based on organic semiconductors. By integrating the capabilities of an image sensor directly into the microdisplay, eye movements can be recorded by the smart glasses and utilized for guidance and control functions, as one example. The new design will be debuted at Augmented World Expo Europe (AWE) in Berlin at Booth B25, October 18th – 19th.

“Augmented-reality” and “wearables” have become terms we encounter almost daily. Both can make daily life a little simpler and provide valuable assistance for...

Im Focus: Artificial Intelligence Helps in the Discovery of New Materials

With the help of artificial intelligence, chemists from the University of Basel in Switzerland have computed the characteristics of about two million crystals made up of four chemical elements. The researchers were able to identify 90 previously unknown thermodynamically stable crystals that can be regarded as new materials. They report on their findings in the scientific journal Physical Review Letters.

Elpasolite is a glassy, transparent, shiny and soft mineral with a cubic crystal structure. First discovered in El Paso County (Colorado, USA), it can also be...

Im Focus: Complex hardmetal tools out of the 3D printer

For the first time, Fraunhofer IKTS shows additively manufactured hardmetal tools at WorldPM 2016 in Hamburg. Mechanical, chemical as well as a high heat resistance and extreme hardness are required from tools that are used in mechanical and automotive engineering or in plastics and building materials industry. Researchers at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden managed the production of complex hardmetal tools via 3D printing in a quality that are in no way inferior to conventionally produced high-performance tools.

Fraunhofer IKTS counts decades of proven expertise in the development of hardmetals. To date, reliable cutting, drilling, pressing and stamping tools made of...

Im Focus: Launch of New Industry Working Group for Process Control in Laser Material Processing

At AKL’16, the International Laser Technology Congress held in May this year, interest in the topic of process control was greater than expected. Appropriately, the event was also used to launch the Industry Working Group for Process Control in Laser Material Processing. The group provides a forum for representatives from industry and research to initiate pre-competitive projects and discuss issues such as standards, potential cost savings and feasibility.

In the age of industry 4.0, laser technology is firmly established within manufacturing. A wide variety of laser techniques – from USP ablation and additive...

Im Focus: New laser joining technologies at ‘K 2016’ trade fair

Every three years, the plastics industry gathers at K, the international trade fair for plastics and rubber in Düsseldorf. The Fraunhofer Institute for Laser Technology ILT will also be attending again and presenting many innovative technologies, such as for joining plastics and metals using ultrashort pulse lasers. From October 19 to 26, you can find the Fraunhofer ILT at the joint Fraunhofer booth SC01 in Hall 7.

K is the world’s largest trade fair for the plastics and rubber industry. As in previous years, the organizers are expecting 3,000 exhibitors and more than...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Experts from industry and academia discuss the future mobile telecommunications standard 5G

23.09.2016 | Event News

ICPE in Graz for the seventh time

20.09.2016 | Event News

Using mathematical models to understand our brain

16.09.2016 | Event News

 
Latest News

Chains of nanogold – forged with atomic precision

23.09.2016 | Life Sciences

New leukemia treatment offers hope

23.09.2016 | Health and Medicine

Self-assembled nanostructures hit their target

23.09.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>