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Strange Object Found -- "The Long-Sought 'Missing Link' That Creates a Neutron Star or Black Hole"

 

 

  Image_1774e-Cassiopeia-A

 

The object, called Supernova 2012ap (SN 2012ap) is what astronomers term a core-collapse supernova. This type of blast occurs when the nuclear fusion reactions at the core of a very massive star no longer can provide the energy needed to hold up the core against the weight of the outer parts of the star. The core then collapses catastrophically into a superdense neutron star or a black hole. The rest of the star's material is blasted into space in a supernova explosion.

Astronomers using the National Science Foundation's Very Large Array (VLA) have found a long-sought "missing link" between supernova explosions that generate gamma-ray bursts (GRBs) and those that don't. The scientists found that a stellar explosion seen in 2012 has many characteristics expected of one that generates a powerful burst of gamma rays, yet no such burst occurred.

"This is a striking result that provides a key insight about the mechanism underlying these explosions," said Sayan Chakraborti, of the Harvard-Smithsonian Center for Astrophysics (CfA). "This object fills in a gap between GRBs and other supernovae of this type, showing us that a wide range of activity is possible in such blasts," he added.

The most common type of such a supernova blasts the star's material outward in a nearly-spherical bubble that expands rapidly, but at speeds far less than that of light. These explosions produce no burst of gamma rays.

In a small percentage of cases, the infalling material is drawn into a short-lived swirling disk surrounding the new neutron star or black hole. This accretion disk generates jets of material that move outward from the disk's poles at speeds approaching that of light. This combination of a swirling disk and its jets is called an "engine," and this type of explosion produces gamma-ray bursts.

The new research shows, however, that not all "engine-driven" supernova explosions produce gamma-ray bursts.

"This supernova had jets moving at nearly the speed of light, and those jets were quickly slowed down, just like the jets we see in gamma-ray bursts," said Alicia Soderberg, also of CfA.

 

Image_2740_1e-SN-2012ap

 

An earlier supernova seen in 2009 also had fast jets, but its jets expanded freely, without experiencing the slowdown characteristic of those that generate gamma-ray bursts. The free expansion of the 2009 object, the scientists said, is more like what is seen in supernova explosions with no engine, and probably indicates that its jet contained a large percentage of heavy particles, as opposed to the lighter particles in gamma-ray-burst jets. The heavy particles more easily make their way through the material surrounding the star.

"What we see is that there is a wide diversity in the engines in this type of supernova explosion," Chakraborti said. "Those with strong engines and lighter particles produce gamma-ray bursts, and those with weaker engines and heavier particles don't," he added.

"This object shows that the nature of the engine plays a central role in determining the characteristics of this type of supernova explosion," Soderberg said.

Chakraborti and Soderberg worked with an international team of scientists from five continents. In addition to the VLA, they also used data from the Giant Meterwave Radio Telescope (GMRT) in India and the InterPlanetary Network (IPN) of spacecraft equipped with GRB detectors. The team, led by Chakraborti, is reporting their work in a paper accepted to the Astrophysical Journal. Other articles, led by co-authors Raffaella Margutti and Dan Milisavljevic, also report on the X-ray and optical follow-up on SN 2012ap using a suite of space and ground-based facilities.

In 2007 NASA’s Spitzer space telescope found the infrared signature of silica (sand) in the core-collapse supernova remnant Cassiopeia A shown at the top of the page The light from this exploding star first reached Earth in the 1600s. The cyan dot just off center is all that remains of the star that exploded. NASA/JPL-Caltech/ O. Krause (Steward Observatory)

Researchers from Washington University in St. Louis report finding tiny grains of silica, which they believe came from a core-collapse supernova, in primitive meteorites.

The Daily Galaxy via NRAO

Comments

There is no nuclear fusion at the core of any star.you cannot collapse something that does not exist.all the heavier elements are produced near the surface of a star.a prime example is the planets in our solar system.these elements are then carried away by the solar winds.

Really mikeyo?? most of the star systems we talk about today, like ours, do not form from pure hydrogen clouds. It is known that our solar system is inside of a supernova bubble. Most the of "metals" that form terrestrial planets and probably the cores of Jovian planets come from the stellar cloud as it condenses into a ring around a proto-star.

You cannot take any comments of mikeyo seriously. Like that of a troll.

@ mica,your putting the cart before the horse.try thinking outside of the box.what needs to happen to create these metals ?.look there is no such thing as a supernova.its a false theoretical term without any validity.just like this notion of a neutron star,this is an impossibility,just like black holes.a basic scientific analysis proves this.neutrons have positive,negative and neutral charges,you cannot keep them together,so how do you think its possible for them to make a star.I give up.

I think a forum's collection of intellect and informational value is best served by posts of those who understand the physics of a super nova event, and solar system(s) formation from the nebula of it. Heavier elements do not form other than fusion of lighter elements and ultimately from a hydrogen nucleus (proton). Period. Nuclear fusion can only take place under extreme pressure which in a star's case is also extreme temperature to crush a lighter nucleus with another to form a heaver nucleus. The pressure it takes to do that isn't possible in the outer layers of any star. That is just simple physics. When you know what it takes to make a neutron from a proton then you can understand partially what goes on in a star's core. Heavier atoms need both protons and neutrons in the nucleus to keep the nucleus from flying apart and you can't magically make a neutron out of a proton on the surface of a star, it is formed deep inside the core. That is fact and thinking --> inside the box and outside both

This is not the place to give a 101 level nuclear physics course but believe me the above is true just as our sky is blue and Sunday follows Saturday.

Really?! Neutrons are all neutral. PROTONS are POSITIVE and ELECTRONS are NEGATIVE in an atom...of course there are other positive and negative particles too. Go back to elementary school and learn that before you comment on a website for smart people.

Mikeyo, you misread my post. No further comment on this subject.

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