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Have astronomers discovered the lightest-ever neutron star? – Innovation News Network

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Using X-ray telescopes in space, astronomers may have discovered the lightest neutron star found so far.

It was discovered by Dr Victor Doroshenko, Dr Valery Suleimanov, Dr Gerd Pühlhofer, and Professor Andrea Santangelo from the High Energy Astrophysics section of the University of Tübingen’s Institute of Astronomy and Astrophysics.

Located at the centre of the supernova remnant, HESS J1731-347, the star has only about half the mass of a typical neutron star.

The findings, published in Nature Astronomy, used new measurements of the distance to a companion star that the team had discovered earlier. This meant that they were able to specify the mass and radius of the star with unprecedented accuracy.

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What are neutron stars?

Neutron stars are formed when normal stars with large masses ‘die’ in a supernova explosion, said the study’s lead author, Victor Doroshenko. According to Doroshenko, these stars are extreme objects that can be regarded as celestial laboratories for studying basic physics.

He explained: “Neutron stars have yet unknown properties of matter, as they have much higher density than atomic nuclei. Conditions like that could not be replicated in terrestrial laboratories.

“Space-based observations of neutron stars with extreme properties such as the one we’ve just found, using X-ray or other telescopes, will allow us to solve the mysteries of super-dense matter. At least if we can solve challenges such as the inaccuracy of measurements over such distances, that arise during observations. We have now succeeded in doing just that, pushing the knowledge about these mysterious objects a bit further.”

Making precise calculations to improve space models

The neutron star at the centre of the supernova remnant HESS J1731-347 was just one of a handful of objects discovered during gamma ray measurements with the telescopes in Namibia. According to Pühlhofer, this was the moment when the cooling neutron star finally became visible.

What makes this object unusual, is that it is connected to another star, which illuminates the dust cloud around the light star, heats it, and makes it shine in the infrared light. The accompanying star was recently observed by the European Space Agency’s Gaia Space Telescope, which provided the research team with accurate distance measurements of both objects.

The Gaia mission involves a high-precision three-dimensional optical survey of the sky. “This allowed us to resolve previous inaccuracies and improve our models,” Pühlhofer said.

“The mass and radius of the neutron star could be determined much more precisely than was previously possible,” added Suleimanov, who is a theoretical astrophysicist.

It is not yet clear how this unusual star formed. There are also doubts as to whether it is actually a neutron star, or whether the object is a candidate for an even more exotic object made of strange quark matter.

Santangelo explained: “This is currently the most promising quark or strange-matter star candidate we know of so far, even if its properties are consistent with those of a ‘normal’ neutron star.” Even if the object at the centre of the supernova remnant is a neutron star, it remains an interesting and puzzling object.

“It allows us to probe the yet unexplored part of the parameter space in the mass-radius plane of neutron stars. This will enable us to put valuable constraints on the equation of state of dense matter, which is used to describe its properties,” Santangelo concluded.

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Scientists revive 48500-year-old ‘zombie virus’ buried in ice

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The thawing of ancient permafrost due to climate change may pose a new threat to humans, according to researchers who revived nearly two dozen viruses – including one frozen under a lake more than 48,500 years ago.

European researchers examined ancient samples collected from permafrost in the Siberia region of Russia. They revived and characterized 13 new pathogens, what they termed “zombie viruses,” and found that they remained infectious despite spending many millennia trapped in the frozen ground.

Scientists have long warned that the thawing of permafrost due to atmospheric warming will worsen climate change by freeing previously trapped greenhouse gases like methane. But its effect on dormant pathogens is less well understood.

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The team of researchers from Russia, Germany and France said the biological risk of reanimating the viruses they studied was “totally negligible” due to the strains they targeted, mainly those capable of infecting amoeba microbes. The potential revival of a virus that could infect animals or humans is much more problematic, they said, warning that their work can be extrapolated to show the danger is real.

“It is thus likely that ancient permafrost will release these unknown viruses upon thawing,” they wrote in an article posted to the preprint repository bioRxiv that hasn’t yet been peer-reviewed.

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“How long these viruses could remain infectious once exposed to outdoor conditions, and how likely they will be to encounter and infect a suitable host in the interval, is yet impossible to estimate.”

“But the risk is bound to increase in the context of global warming when permafrost thawing will keep accelerating, and more people will be populating the Arctic in the wake of industrial ventures,” they said.

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McMaster University team to finalize plans with CSA on deployment of satellite

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A team of students from McMaster University which has spent close to seven years creating a satellite to measure space radiation is set to finalize plans to deploy the device in outer space.

The Canadian Space Agency (CSA) is welcoming the developers this week to finalize preparation of their CubeSat, a miniaturized satellite to further the understanding of long-term exposure to space radiation.

Operation Team Lead with McMaster’s NEUtron DOSimetry & Exploration (NEUDOSE) mission Taren Ginter says the idea was selected for the Canadian Cube Sat project in 2018. In simple terms, Ginter says it measures the effects of ionizing radiation on the human body.

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Some of the financial backing for the project came in the form of $200,000 awarded to the McMaster developers by the CSA.

Ginter says as spaceflight and deep-space missions become a reality in the future, astronauts will likely have to face radiation that is distinct from the radiation experienced on earth.

The question the NEUDOSE mission is looking to answer is what kind and how much radiation astronauts will face on a multi-year mission in space.

“So our goal is to get a sense of those radiation differences and hopefully we can implement better safety precautions so that astronauts are protected,” Ginter explained.

The McMaster radiation detector is the size of a loaf of bread and is expected to be placed in a small satellite prior to being deployed into space, free floating like an astronaut would.

If it works properly, the device will send real-time radiation measurements back to the team at the university.

The device is the concept of Dr. Andrei Hanu, who came up with the idea while working at NASA as a research scientist.

Hanu led the first team of developers in 2015, jokingly referring to the device as the “igloo” due to its top which is dome-shaped.

However, Ginter says the satellite will actually look like a bunch of solar panels connected together due to the fact it needs to be charged by sunlight.

“But inside of the satellite, we have our charged and neutral particle tissue equivalent proportional counter, which is quite a mouthful,” Ginter said.

“So this is the actual payload of our satellite that will be looking at the radiation in low-earth orbit and then sending that information back down to ground station at McMaster.”

The NEUDOSE CubeSat will head to the CSA this week for a final step confirming it meets standards to be deployed from the International Space Station (ISS).

The life expectancy of the device is approximately one year in the Earth’s orbit after it’s been deployed.

The McMaster creation is earmarked for the ISS in February following launch from a SpaceX Dragon ship in Florida.

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Explainable AI-based physical theory for advanced materials design: Scientists develop an ‘extended Landau free energy model’ for causal analysis and visualization in nano-magnetic devices with AI and topology

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Microscopic materials analysis is essential to achieve desirable performance in next-generation nanoelectronic devices, such as low power consumption and high speeds. However, the magnetic materials involved in such devices often exhibit incredibly complex interactions between nanostructures and magnetic domains. This, in turn, makes functional design challenging.

Traditionally, researchers have performed a visual analysis of the microscopic image data. However, this often makes the interpretation of such data qualitative and highly subjective. What is lacking is a causal analysis of the mechanisms underlying the complex interactions in nanoscale magnetic materials.

In a recent breakthrough published in Scientific Reports, a team of researchers led by Prof. Masato Kotsugi from Tokyo University of Science, Japan succeeded in automating the interpretation of the microscopic image data. This was achieved using an “extended Landau free energy model” that the team developed using a combination of topology, data science, and free energy. The model could illustrate the physical mechanism as well as the critical location of the magnetic effect, and proposed an optimal structure for a nano device. The model used physics-based features to draw energy landscapes in the information space, which could be applied to understand the complex interactions at the nanoscales in a wide variety of materials.

“Conventional analysis are based on a visual inspection of microscope images, and the relationships with the material function are expressed only qualitatively, which is a major bottleneck for material design. Our extended Landau free energy model enables us to identify the physical origin and location of the complex phenomena within these materials. This approach overcomes the explainability problem faced by deep learning, which, in a way, amounts to reinventing new physical laws,” Prof. Kotsugi explains. This work was supported by KAKENHI, JSPS, and the MEXT-Program for Creation of Innovative Core Technology for Power Electronics Grant.

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When designing the model, the team made use of the state-of-art technique in the fields of topology and data science to extend the Landau free energy model. This led to a model that enabled a causal analysis of the magnetization reversal in nanomagnets. The team then carried out an automated identification of the physical origin and visualization of the original magnetic domain images.

Their results indicated that the demagnetization energy near a defect gives rise to a magnetic effect, which is responsible for the “pinning phenomenon.” Further, the team could visualize the spatial concentration of energy barriers, a feat that had not been achieved until now. Finally, the team proposed a topologically inverse design of recording devices and nanostructures with low power consumption.

The model proposed in this study is expected to contribute to a wide range of applications in the development of spintronic devices, quantum information technology, and Web 3.

“Our proposed model opens up new possibilities for optimization of magnetic properties for material engineering. The extended method will finally allow us to clarify ‘why’ and ‘where’ the function of a material is expressed. The analysis of material functions, which used to rely on visual inspection, can now be quantified to make precise functional design possible,” concludes an optimistic Prof. Kotsugi.

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