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Magnetic Jet Shows How Stars Begin Their Final Transformation

September 19, 2013 Leave a comment

Credits: E. Lagadec/ESO/A. Pérez Sánchez

Credits: E. Lagadec/ESO/A. Pérez Sánchez

An international team of astronomers have for the first time found a jet of high-energy particles emanating from a dying star. The discovery, by a collaboration of scientists from Sweden, Germany and Australia, is a crucial step in explaining how some of the most beautiful objects in space are formed – and what happens when stars like the sun reach the end of their lives. The researchers publish their results in the journal Monthly Notices of the Royal Astronomical Society.

At the end of their lives, stars like the sun transform into some of the most beautiful objects in space: amazing symmetric clouds of gas called planetary nebulae. But how planetary nebulae get their strange shapes has long been a mystery to astronomers.

Scientists at Chalmers University of Technology in Sweden have together with colleagues from Germany and Australia discovered what could be the key to the answer: a high-speed, magnetic jet from a dying star.

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New Hubble Image Of Galaxy Cluster Abell 1689

September 19, 2013 1 comment

Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)

Image credit: NASA, ESA, the Hubble Heritage Team (STScI/AURA), J. Blakeslee (NRC Herzberg Astrophysics Program, Dominion Astrophysical Observatory), and H. Ford (JHU)

Hubble previously observed this cluster back in 2002. However, this new image combines visible and infrared data from Hubble’s Advanced Camera for Surveys (ACS) to reveal this patch of sky in greater detail than ever before, with a combined total exposure time of over 34 hours.

These new, deeper, observations were taken in order to explore the globular clusters within Abell 1689 [1]. This new study has shown that Abell 1689 hosts the largest population of globular clusters ever found. While our galaxy, the Milky Way, is only home to around 150 of these old clumps of stars, Hubble has spied some 10 000 globular clusters within Abell 1689. From this, the astronomers estimate that this galaxy cluster could possibly contain over 160 000 globulars overall – an unprecedented number.

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NASA’s Voyager 1 Reaches Interstellar Space

September 19, 2013 Leave a comment

NASA’s Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.

New and unexpected data indicate Voyager 1 has been traveling for about one year through the plasma, or ionized gas, present in the space between the stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of these new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published this week in the journal Science.

“The crossing is like Voyager leaving the hot, million-degree atmosphere of the sun and entering into a region dominated by the ‘cold,’ 5,000-degree atmosphere of the galaxy,” says APL’s Stamatios (Tom) Krimigis, principal investigator for Voyager’s Low-Energy Charged Particle (LECP) instrument. “It’s like the first time a satellite [Sputnik] went beyond Earth’s atmosphere to an altitude of some 600 miles; Voyager is now leaving the solar bubble at an altitude of 11.3 billion miles. It’s another historic milestone.”

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“Red Nugget” Galaxies Were Hiding In Plain Sight

September 19, 2013 1 comment

In 2005 the Hubble Space Telescope spotted unusually small galaxies densely packed with red stars in the distant, young universe. They were nicknamed “red nuggets,” not only because they are small and red but also their existence challenged current theories of galaxy formation, making them precious in astronomers’ eyes.

Since no “red nuggets” were seen nearby, astronomers wondered why they had disappeared over time. New research shows that they didn’t disappear completely. In fact, they were simply hidden within the data of previous surveys.

Astronomers now realize these newfound compact galaxies could represent a missing link between distant “red nuggets” and nearby elliptical galaxies. They may light the evolutionary path to show how compact galaxies age over time and reveal whether they become the “seeds” for the monster ellipticals we see today.

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EPSC2013: Get Ready For Rosetta’s Wake-Up Call With Activity Schedule For Target Comet

September 19, 2013 1 comment

After a journey of almost ten years, the Rosetta mission has just a few months left to wait before beginning its rendezvous with a time capsule. Comet 67P/Churymov-Gerasimenko is a dirty snowball of ice and dust that preserves material from the formation of the Solar System 4.5 billion years ago. During 2014, the European Space Agency’s most ambitious mission to date will both start to orbit the comet’s nucleus and deploy a small laboratory of scientific instruments, Philae, to dock with the comet’s surface. To aid Rosetta in safely achieving its task, an international group of scientists back on Earth are using ground-based telescopes and computer models to understand the behaviour of the comet as it approaches the Sun and begins to form its tail. Their findings have been presented this week at the European Planetary Science Congress (EPSC) 2013 at University College London.

“For two or three orbits now, our community has been observing the comet to determine the shape of the nucleus, the angle at which it spins on its axis and how its activity varies as it orbits the Sun. All of this information is vital for the planning of Rosetta’s orbit and Philae’s delivery,” said Jessica Agarwal of the Max Planck Institute for Solar System Research (MPS).

“At this meeting, we have discussed everything from the make-up of the surface layer of the nucleus to the dust production rates, size and velocity of the particles emitted, the way the comet interacts with the solar magnetic environment… There are a lot of things we need to know!” added Matt Taylor, ESA’s Project Scientist for the Rosetta Mission.

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Map Of Galactic Clouds Takes Shape

September 19, 2013 Leave a comment

A UNSW-led team of astronomers has begun to map the location of the most massive and mysterious objects in our galaxy – the giant gas clouds where new stars are born.

Using a telescope at Coonabarabran that narrowly escaped devastation in a recent bushfire, the team identifies the galactic clouds of molecular gas – which can be up to 100 light years across – from the carbon monoxide they contain.

“On Earth, carbon monoxide is poisonous – a silent killer. But in space, it is the second most abundant molecule and the easiest to see,” says Professor Michael Burton, of the UNSW School of Physics, who leads the team. “One of the largest unresolved mysteries in galactic astronomy is how these giant, diffuse clouds form in the interstellar medium. This process plays a key role in the cosmic cycle of birth and death of stars.”

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Professor Helps To Discover Near-Earth Asteroid Is Really A Comet

September 16, 2013 Leave a comment

Some things are not always what they seem—even in space. For thirty years, scientists believed a large near-Earth object was an asteroid. Now, an international team including Joshua Emery, assistant professor of earth and planetary sciences at UT, has discovered it is actually a comet.

Called 3552 Don Quixote, the body is the third largest near-Earth object—mostly rocky bodies, or asteroids, that orbit the Sun in the vicinity of Earth. About 5 percent of near-Earth objects are thought to be “dead” comets that have shed all the water and carbon dioxide in the form of ice that give them their coma—a cloud surrounding the comet nucleus—and tail.

The team found that Don Quixote is neither. It is, in fact, an active comet, thus likely containing water ice and not just rocks. The finding will be presented at the European Planetary Science Congress 2013 in London today, Sept. 10. The discovery could hold implications for the origin of water on Earth.

Full Story: http://www.utk.edu/tntoday/2013/09/10/professor-helps-discover-nearearth-asteroid-comet/