Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Supernova leaves behind mysterious object

Thanks to data from ESA’s XMM-Newton satellite, a team of scientists taking a closer look at an object discovered over 25 years ago have found that it is like none other known in our galaxy.

The object is in the heart of supernova remnant RCW103, the gaseous remains of a star that exploded about 2 000 years ago. Taken at face value, RCW103 and its central source would appear to be a textbook example of what is left behind after a supernova explosion: a bubble of ejected material and a neutron star.

This image, obtained thanks to ESA's XMM-Newton X-ray telescope on 23 August 2005, shows the aftermath of a 2000-year-old star explosion. In the heart of the central blue dot in this image, smaller than a pinpoint, likely lies a neutron star only about 20 kilometers across. The nature of this object is like nothing detected before. Scientists from the Istituto Nazionale di Astrofisica (INAF) in Milan have detected unusual X-ray pulsations. Understanding the central source's true nature will lead to new insights about supernovae, neutron stars and their evolution. Credits: ESA/XMM-Newton/A.De Luca (INAF-IASF )

A deep, continuous 24.5-hour observation has revealed something far more complex and intriguing, however. The team, from the Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF) of the Istituto Nazionale di Astrofisica (INAF) in Milan, Italy, has found that the emission from the central source varies with a cycle that repeats itself every 6.7 hours. This is an astonishingly long period, tens of thousands of times longer than expected for a young neutron star. Also, the object's spectral and temporal properties differ from an earlier XMM-Newton observation of this very source in 2001.

"The behaviour we see is especially puzzling in view of its young age, less than 2 000 years," said Andrea De Luca of IASF-INAF, the lead author. "It is reminiscent of a multimillion-year-old source. For years we have had a sense that the object is different, but we never knew how different until now."

The object is called 1E161348-5055, which the scientists have conveniently nicknamed 1E (where E stands for Einstein Observatory which discovered the source). It is embedded nearly perfectly in the centre of RCW 103, about 10 000 light years away in the constellation Norma. The near-perfect alignment of 1E in the centre of RCW 103 leaves astronomers rather confident that the two were born in the same catastrophic event.

When a star at least eight times more massive than our sun runs out of fuel to burn, it explodes in an event called a supernova. The stellar core implodes, forming a dense nugget called a neutron star or, if there's enough mass, a black hole. A neutron star contains about a sun's worth of mass crammed into a sphere only about 20 kilometres across.

Scientists have searched for years for 1E's periodicity in order to learn more about its properties, such as how fast it is spinning or whether it has a companion.

"Our clear detection of such a long period together with secular variability in X-ray emission makes for a very weird source," said Patrizia Caraveo of INAF, a co-author and leader of the Milano Group. "Such properties in a 2000-year-old compact object leave us with two probable scenarios, essentially a source that is accretion-powered or magnetic-field-powered."

1E could be an isolated magnetar, an exotic subclass of highly magnetized neutron stars. Here, the magnetic field lines act as brakes for the spinning star, liberating energy. About a dozen magnetars are known. But magnetars usually spin several times per minute. If 1E is spinning only once every 6.67 hours, as the period detection indicates, the magnetic field needed to slow the neutron star in just 2000 years would be too big to be plausible.

A standard magnetar magnetic field could do the trick, however, if a debris disk, formed by leftover material of the exploded star, is also helping to slow down the neutron star spin. This scenario has never been observed before and would point to a new type of neutron star evolution.

Alternatively, the long 6.67-hour period could be the orbital period of a binary system. Such a picture requires that a low-mass normal star managed to remain bound to the compact object generated by the supernova explosion 2000 year ago. Observations do allow for a companion of half the mass of our Sun, or even smaller.

But 1E would be an unprecedented example of a low-mass X-ray binary system in its infancy, a million times younger than standard X-ray binary systems with light companions. Young age is not the only peculiarity of 1E. The source's cyclic pattern is far more pronounced than that observed for dozens of low-mass X-ray binary systems calling for some unusual neutron star feeding process.

A double accretion process could explain its behaviour: The compact object captures a fraction of the dwarf star's wind (wind accretion), but it is also able to pull out gas from the outer layers of its companion, which settles in an accretion disc (disc accretion). Such an unusual mechanism could be at work in an early phase of the life of a low-mass X-ray binary, dominated by the effects of the initial, expected, orbital eccentricity.

"RCW 103 is an enigma," said Giovanni Bignami, director of CESR,Toulouse, and co-author. "We simply don't have a conclusive answer to what is causing the long X-ray cycles. When we do figure this out, we're going to learn a lot more about supernovae, neutron stars and their evolution."

Had the star exploded in the northern sky, Cleopatra could have seen it and considered it to be an omen of her unhappy end, Caraveo said. Instead the explosion took place deep in the southern sky, and no one recorded it. Nevertheless, the source is a good omen for X-ray astronomers hoping to learn about stellar evolution.

Norbert Schartel | alfa
Further information:

More articles from Physics and Astronomy:

nachricht Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR

nachricht Taming chaos: Calculating probability in complex systems
21.03.2018 | American Institute of Physics

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: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Modular safety concept increases flexibility in plant conversion

22.03.2018 | Trade Fair News

New interactive map shows climate change everywhere in world

22.03.2018 | Earth Sciences

New technologies and computing power to help strengthen population data

22.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>