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Archive for February 24, 2014

With A Deadly Embrace, ‘Spidery’ Pulsars Consume Their Mates

February 24, 2014 Leave a comment

Artist's concept. Image Credit: NASA's Goddard Space Flight Center

Artist’s concept. Image Credit: NASA’s Goddard Space Flight Center

Black widow spiders and their Australian cousins, known as redbacks, are notorious for their tainted love, expressed as an unsettling tendency to kill and devour their male partners. Astronomers have noted similar behavior among two rare breeds of binary system that contain rapidly spinning neutron stars, also known as pulsars.

“The essential features of black widow and redback binaries are that they place a normal but very low-mass star in close proximity to a millisecond pulsar, which has disastrous consequences for the star,” said Roger Romani, a member of the Kavli Institute for Particle Astrophysics and Cosmology, an institute run jointly by Stanford and SLAC National Accelerator Laboratory in Menlo Park, Calif. Black widow systems contain stars that are both physically smaller and of much lower mass than those found in redbacks.

So far, astronomers have found at least 18 black widows and nine redbacks within the Milky Way, and additional members of each class have been discovered within the dense globular star clusters that orbit our galaxy.

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Subaru Telescope Detects Rare Form Of Nitrogen In Comet ISON

February 24, 2014 Leave a comment

A team of astronomers, led by Ph.D. candidate Yoshiharu Shinnaka and Professor Hideyo Kawakita, both from Kyoto Sangyo University, successfully observed the Comet ISON during its bright outburst in the middle of November 2013. Subaru Telescope’s High Dispersion Spectrograph (HDS) detected two forms of nitrogen–14NH2 and 15NH2–in the comet. This is the first time that astronomers have reported a clear detection of the relatively rare isotope 15NH2 in a single comet and also measured the relative abundance of two different forms of nitrogen (“nitrogen isotopic ratio”) of cometary ammonia (NH3). Their results support the hypothesis that there were two distinct reservoirs of nitrogen the massive, dense cloud (“solar nebula”) from which our Solar System may have formed and evolved.

Why did the team focus on studying these different forms of nitrogen in the comet? Comets are relatively small Solar System objects composed of ice and dust, which formed 4.6 billion years ago in the solar nebula when our Solar System was in its infancy. Because they usually reside in cold regions far from the Sun, e.g., the Kuiper belt and Oort cloud, they probably preserve information about the physical and chemical conditions in the early Solar System. Different forms and abundances of the same molecule provide information about their source and evolution. Were they from a stellar nursery (a primordial interstellar cloud) or from a distinctive cloud (solar nebula) that may have formed our Solar System’s star, the Sun? Scientists do not yet understand very well how cometary molecules separate into isotopes with different abundances. Isotopes of nitrogen from ammonia (NH3) may hold the key.

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Study: Remote Antarctic Telescope Reveals Giant Gas Cloud

February 24, 2014 Leave a comment

Using a telescope installed at the driest place on earth – Ridge A in Antarctica – a UNSW-led team of researchers has identified a giant gas cloud which appears to be in an early stage of formation. Giant clouds of molecular gas – the most massive objects in our galaxy – are the birthplaces of stars.

“This newly discovered gas cloud is shaped like a very long filament, about 200 light years in extent and ten light years across, with a mass about 50,000 times that of our sun,” says team leader, Professor Michael Burton, an astronomer at UNSW Australia. “The evidence suggests it is in the early stages of formation, before any stars have turned on.

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Astronomers Find Solar Storms Behave Like Supernovae

February 24, 2014 Leave a comment

Photo credit: NASA/SDO

Photo credit: NASA/SDO

Researchers at UCL have studied the behaviour of the Sun’s coronal mass ejections, explaining for the first time the details of how these huge eruptions behave as they fall back onto the Sun’s surface. In the process, they have discovered that coronal mass ejections have a surprising twin in the depths of space: the tendrils of gas in the Crab Nebula, which lie 6500 light-years away and are millions of times larger.

On 7 June 2011, the biggest ejection of material ever observed erupted from the surface of the Sun. Over the days that followed, the plasma belched out by the Sun made its way out into space. But most of the material propelled up from the Sun’s surface quickly fell back towards our star’s surface.

For the solar physicists at UCL’s Mullard Space Science Laboratory, watching these solar fireworks was a unique opportunity to study how solar plasma behaves.

“We’ve known for a long time that the Sun has a magnetic field, like the Earth does. But in places it’s far too weak for us to measure, unless we have something falling through it. The blobs of plasma that rained down from this beautiful explosion were the gift we’d been waiting for”, says David Williams, one of the study’s authors.

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