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Supernova remnant
 
Supernova Remnant: A long observation with Chandra of the supernova remnant MSH 11-62 reveals an irregular shell of hot gas, shown in red, surrounding an extended nebula of high energy X-rays, shown in blue. Even though scientists have yet to detect any pulsations from the central object within MSH 11-62, the structure around it has many of the same characteristics as other pulsar wind nebulas. The reverse shock and other, secondary shocks within MSH 11-62 appear to have begun to crush the pulsar wind nebula, possibly contributing to its elongated shape. (Note: the orientation of this image has been rotated by 24 degrees so that north is pointed to the upper left.)

Image credit: NASA/CXC/SAO/P. Slane et al.

#nasa #chandra #xray#astronomy #space #nebula #science #supernova

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Touchdown!

The comet lander Philae successfully attached itself to the surface of the comet.

A historical day: The first comet landing.

Congratulations!
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There is a star with a calculated age that is older than the universe. That might seem like a contradiction, but it's not.
The star HD 140283 is a subgiant star with an estimated age of 14.46 billion years. That might raise an eyebrow or two for those of you who remember that the age of the universe is estimated as 13.77 billion years. It would seem that this particular star, sometimes referred to as the Methuselah star is older than the universe.
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Star Seed

One of the big mysteries in cosmology is how supermassive black holes formed in the centers of galaxies. Did they form directly from large concentrations of matter and dark matter, or did they form when early stars collided and accreted into massive black holes? Another idea is that they may have formed from the collapse of supermassive stars. In this idea stars with masses of 10,000 Suns or more could have lived short, violent lives before their core collapsed into a massive black hole. It’s an interesting idea, but new research shows that such supermassive stars might have a different fate.

This new research has been published in the Astrophysical Journal, and it looks at computer simulations of early supermassive stars. The team ran simulations of primordial (population III) stars with masses around 55,000 solar masses. At this scale, a simple hydrodynamic model doesn’t work. You need to account for the effects of general relativity as well as things like photodissociation, where the intense light of a star can break apart the nuclei of atoms. The team found that such stars can only survive for about 1.7 million years before becoming unstable.

This isn’t too surprising, but what is surprising is that for stars around this mass instead of dying as a core-collapse supernova, which would produce a massive black hole, instabilities cause the star to rip apart completely, leaving no remnant core. What’s more, a good fraction of the star’s mass has been fused into “metals” or elements beyond hydrogen and helium. As a result, such stars could provide a mechanism for the early enrichment of heavy elements in the universe.

The authors go on to point out that such a stellar explosion might be observable in the distant universe. If such stellar explosions occurred, they would be seen in the near infrared, looking similar to supernovae with high redshift (around z = 20). But because of the intense mixing of elements in the star, the explosion would look distinctly different from usual supernovae. Right now we don’t have the ability to observe such explosions, but future missions such as the Euclid infrared telescope (scheduled to be launched in 2020) might be capable.

So we haven’t solved the mystery of supermassive black holes, but we may have discovered a new way for early stars to seed the universe with heavy elements.

Image: Ke-Jung Chen, et al.

Paper: Ke-Jung Chen et al. The General Relativistic Instability Supernova of a Supermassive Population III Star.  ApJ 790 162 (2014)
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Some supernovae are much brighter than usual. Superluminous supernovae, as they are sometimes known. Recent observations of some of these hint at a new kind of supernova known as a pair-instability supernova.
A supernova is a stellar explosion. They can occur when a large star exhausts its ability to fuse hydrogen into higher elements, and its core collapses. The resulting rebound rips apart the outer layers of the star, creating a supernova while the remains of the core collapses into a neutron star. Another type of supernova, known as a thermal runaway or type Ia, occurs when a white dwarf is a close companion with another star. As outer layers of t...
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Gaia finds first supernova

The Gaia satellite scans the sky to measure positions and movements of stars but its repeated observations also may discover stellar explosions. It just proved this by finding its first explosive event. And many more are expected to follow: "In a few months, they expect Gaia to discover about three new supernovas every day."
 
While scanning the sky to measure the positions and movements of stars in our Galaxy, Gaia has discovered its first stellar explosion in another galaxy far, far away. This powerful event, now named Gaia14aaa, took place in a distant galaxy some 500 million light-years away, and was revealed via a sudden rise in the galaxy's brightness between two Gaia observations separated by one month.

http://sci.esa.int/gaia/54630-gaia-discovers-its-first-supernova/

#Gaia   #supernova   #stellar   #galaxy  
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Studying the aftermath of a supernova explosion
 
Astronomers dissect the aftermath of a Supernova.

A team of astronomers has used radio telescopes in Australia and Chile to see inside the remains of a supernova. The supernova, known as SN1987A, was first seen by observers in the Southern Hemisphere in 1987 when a giant star suddenly exploded at the edge of a nearby dwarf galaxy called the Large Magellanic Cloud. Learn more: http://buff.ly/1AYnGd7
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The Cat's Eye Nebula - remains of a star

Seen with the Hubble Space Telescope, these expanding shells of gas are three thousand light-years away from Earth and about half a light year across. In the center of this nebula is a dying star, a sun-like star that has shrugged off its outer layers in several pulses, as seen by the concentric shells of gas moving outwards. The innermost structures seem to indicate more violent activity which currently is not well understood yet but may be due to a core He-flash, a violent phase of nuclear burning. In the end, a hot White Dwarf will be formed in the center that will just cool down while the ejected gas clouds keep expanding and cooling as well. The typical final fate of a low-mass star and our Sun will meet the same fate in 4.5 billion years.

Image Credit: NASA, ESA, HEIC, and The Hubble Heritage Team (STScI/AURA)
A different astronomy and space science related image is featured each day, along with a brief explanation.
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From the HAP website: The neutrino experiment Borexino  in the INFN  Gran Sasso Laboratories has managed to measure the energy of our star in real time: the energy released today at the centre of the Sun is exactly the same as that produced 100,000 years ago.

-- The Sun as Borexino Sees It in Real Time
http://www.hap-astroparticle.org/news.php#block405

#neutrinos #BOREXINO #Nature #astroparticle #HAPnews #whatyoumighthavemissedwhenIwasaway  
The neutrino experiment Borexino in the INFN Gran Sasso Laboratories has managed to measure the energy of our star in real time: the energy released today at the centre of the Sun is exactly the same as that produced 100000 years ago. For the first time in the history of scientific investigation ...
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If this doesn't fascinate you,  I don't know what will.
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INTERNATIONAL SCHOOL OF NUCLEAR PHYSICS
36th Course
Nuclei in the Laboratory and in the Cosmos
Erice-Sicily: September 16-24, 2014

The purpose of the meeting is to bring together experts and young researchers in the area of nuclear structure physics and nuclear astrophysics to discuss the current status of the field and to explore future directions, both in experiment and theory. With recent developments in instrumentation, theoretical tools and numerical simulations as well as significant progress in experiment and observation, the meeting is particularly timely. The aim is to cover a broad range of topics to elucidate synergies and identify areas of future progress. This should be especially beneficial to the younger participants of the meeting.

In detail, the following topics will be presented and discussed:
- Lattice QCD and light nuclei
- Nuclear structure from chiral EFT interactions
- Ab-initio methods for medium-mass nuclei
- Single-particle and collective dynamics
- Nuclear structure far from the line of stability
- Nuclei as a laboratory for beyond the Standard Model physics
- Neutron star matter
- Stellar burning
- Exploding stars and binary mergers of compact objects
- Nuclear synthesis in cosmic events
- Neutrino production in stars and supernova explosions
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Hubble finds companion star in supernova type IIb remnant

A type IIb supernova is hypothesized to be the explosion of a massive star in a binary system after it lost most of its hydrogen envelope to its companion star. So far, it was not possible to directly detect the companion star to support the hypothesis. The spectral lines of the suspected companion star could be identified in the new Hubble data, thus confirming the leading model for type IIb supernovae.

For details, see also http://hubblesite.org/newscenter/archive/releases/2014/38/full/
 
Hubble Finds Companion Star Hidden for 21 Years in a Supernova's Glare

For over two decades astronomers have been patiently monitoring the fading glow of a supernova in a nearby galaxy. They've been looking for a suspected companion star that pulled off almost all of the hydrogen from the doomed star that exploded. At last Hubble's ultraviolet-light sensitivity pulled out the blue glow of the star from the cluttered starlight in the disk of the galaxy.

This observation confirms the theory that the supernova originated in a double-star system where one star fueled the mass-loss from the aging primary star. The surviving star's brightness and estimated mass provide insight into the conditions that preceded the 1993 explosion.

Read more here:
http://hubblesite.org/newscenter/archive/releases/2014/38/
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