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Archive for February, 2014

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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Diamonds In The Tail Of The Scorpion

February 19, 2014 Leave a comment

Credit: ESO

Credit: ESO

A new image from ESO’s La Silla Observatory in Chile shows the bright star cluster Messier 7. Easily spotted with the naked eye close to the tail of the constellation of Scorpius, it is one of the most prominent open clusters of stars in the sky — making it an important astronomical research target.

Messier 7, also known as NGC 6475, is a brilliant cluster of about 100 stars located some 800 light-years from Earth. In this new picture from the Wide Field Imager on the MPG/ESO 2.2-metre telescope it stands out against a very rich background of hundreds of thousands of fainter stars, in the direction of the centre of the Milky Way.

At about 200 million years old, Messier 7 is a typical middle-aged open cluster, spanning a region of space about 25 light-years across. As they age, the brightest stars in the picture — a population of up to a tenth of the total stars in the cluster — will violently explode as supernovae. Looking further into the future, the remaining faint stars, which are much more numerous, will slowly drift apart until they become no longer recognisable as a cluster.

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NASA’s NuSTAR Untangles Mystery Of How Stars Explode

February 19, 2014 Leave a comment

Image credit: NASA/JPL-Caltech/CXC/SAO

Image credit: NASA/JPL-Caltech/CXC/SAO

One of the biggest mysteries in astronomy, how stars blow up in supernova explosions, finally is being unraveled with the help of NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR).

The high-energy X-ray observatory has created the first map of radioactive material in a supernova remnant. The results, from a remnant named Cassiopeia A (Cas A), reveal how shock waves likely rip apart massive dying stars.

“Stars are spherical balls of gas, and so you might think that when they end their lives and explode, that explosion would look like a uniform ball expanding out with great power,” said Fiona Harrison, the principal investigator of NuSTAR at the California Institute of Technology (Caltech) in Pasadena. “Our new results show how the explosion’s heart, or engine, is distorted, possibly because the inner regions literally slosh around before detonating.”

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Astronomers At The National Observatory Continue To Watch Sn 2014J

February 19, 2014 Leave a comment

SN2014J-4m_smThe astronomical community was very excited by the appearance of a supernova in a relatively nearby galaxy in late January 2014. Observations of this supernova, located in the galaxy M 82, and referred to as SN2014J revealed that it is a type Ia. These occur in a binary star system composed of a dense white dwarf star and a companion star, either another white dwarf or a bloated red giant star. These supernovae are especially interesting because they provide one of the best ways to measure distances to faint galaxies, and therefore calibrate the expansion of the universe. At Kitt Peak National Observatory (KPNO), two different teams have been observing SN2014J.

At the Mayall 4-meter telescope on KPNO Dr. Ginger Bryngelson (Francis Marion University) and Dina Drozdov (Clemson University) were serendipitously engaged in a program to observe the slow fading of other previously known Ia supernovae when SN2014J was first spotted, and immediately added this one to their program. As Ms. Drozdov said,” Since this one is so nearby, we will be able to monitor it for much longer past its explosion than others. It will become one of the most widely-studied in history.”

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Clouds Circling Supermassive Black Holes

February 19, 2014 Leave a comment

Artist's concept. Credit: NASA / JPL / Caltech

Artist’s concept. Credit: NASA / JPL / Caltech

Astronomers see huge clouds of gas orbiting supermassive black holes at the centres of galaxies. Once thought to be a relatively uniform, fog-like ring, the accreting matter instead forms clumps dense enough to intermittently dim the intense radiation blazing forth as these enormous objects condense and consume matter.

The international team reports their sightings in a paper to be published in the Monthly Notices of the Royal Astronomical Society, available online now. Videos depicting the swirling clouds are posted to YouTube.

Evidence for the clouds comes from records collected over 16 years by NASA’s Rossi X-ray Timing Explorer, a satellite in low-earth orbit equipped with instruments that measured variations in X-ray sources. Those sources include active galactic nuclei, brilliantly luminous objects powered by supermassive black holes as they gather and condense huge quantities of dust and gas.

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