Supernova

[The Code]

G Day harry

When is matter not matter? when its half energy?

[Chris Peterson]

The core has a high density, its grvity controlls the heat release and the prevention of the solar envelope from expanding.

Over billions of years the core loses mass and thus the ability to control the heat release from the core and the temp lid within the solar envelope, this temp expands the solar envelope.

The high energy photons originating from the core and reconnecting electromagnetic fields break up the heavier elements by photodisintergration.

During the process the core is rejuvinated and may even go through a phase transition to Neutrons or a pasta of subatomic particles that may include quarks. The composition of the core is complicated by the size of the Star.

There isn't a single correct statement in that group.

[Chris Peterson]

When is matter not matter? when its half energy?

Matter isn't usually though of a fundamental thing. It is a form of energy, and when we consider the energy content of the Universe, that includes matter.

Matter, of course, can be created. It merely involves the conversion of energy.

[harry]

G'day

This info may help

http://burro.astr.cwru.edu/stu/advanced/index.html

http://burro.astr.cwru.edu/stu/advanced ... death.html

Supernova

With nothing less to fuse, gravity wins out against a now non-existent outward pressure, and compresses the core. As it is squeezed, it becomes degenerate, and is held up by degeneracy pressure. However, now photons have enough energy to destroy nuclei:

56 Fe plus High energy photons gives you 13 He plus 4 N
4Helium plus high enery photons give you 2 Protons and 2Neutrons


This is known as photodisintegration, but it uses energy rather than creates it. In the extreme conditions at the core of such a star, free protons capture the free electrons, producing a neutron and an electron neutrino. However, remember that the electrons were what was holding up the core against gravity.

With the sudden release of the degeneracy pressure, the core again starts to collapse, but this time there is nothing to stop it. The effective free-fall depends on density, and since the density increases the closer to the center, the inner portions of the star react first. With collapse speeds of about 70,000 km/s, the inner core collapses from about 1 REarth to 50 km in one second.

As the core collapses, the outer layers have nothing to support them, and they collapse inwards, too. Once the density reaches about 1015 gm/cm3, the collapse is again halted. This is about the density of an atomic nucleus. The stop of collapse is caused by neutron degeneracy.

The core rebounds a little, sending out a shock wave. As this shockwave travels out, it eventually meets the shockwave of material falling in. When this occurs, there is a tremendous explosion called a Type II supernova.

The outer layers are blast off in a violent explosion. When they become optically thin, the energy escapes and we can see it. The peak optical luminosity for a typical Type II supernova is approximately 109 LSun. Approximately 100 times more energy is released in the form of neutrinos. The net effect is a brightness that outshines an entire galaxy.

In addition protons with the addition of an electron form a Neutron. The end result is a confinement of Neutrons in a zone that is able to keep them stable for billions of years.

[The Code]

When is matter not matter? when its half energy?

Matter isn't usually though of a fundamental thing. It is a form of energy, and when we consider the energy content of the Universe, that includes matter.

Matter, of course, can be created. It merely involves the conversion of energy.

Matter can not be created or destroyed ,,, come on chris you know this...

http://en.wikipedia.org/wiki/Conservation_of_mass

[harry]

G'day

Chris said

Chris Peterson wrote:
mark swain wrote:
When is matter not matter? when its half energy?
Matter isn't usually though of a fundamental thing. It is a form of energy, and when we consider the energy content of the Universe, that includes matter.

Matter, of course, can be created. It merely involves the conversion of energy.

He did not say matter created from nothing.
He said the creation of matter by conversion of energy.

as per

E = MC ^2 M=E / C^2

When you compact matter to the extremes such as Neutrino matter, once ejected to space it reforms normal matter as we know it. In actual fact normal matter in space is degenerate matter found in compact objects such as Neutro Star, Quark Stars and so on to the ultimate so called Black Hole (without a singularity).

[The Code]

What you see in our universe happened 13.7 seconds ago or 13.7 billion years ago..

The space it created could be meaningless....

[Chris Peterson]

Matter can not be created or destroyed ,,, come on chris you know this...

Matter can be converted to energy, and energy to matter. Energy is seen as the most fundamental state, since that's all that was present at the beginning of the Universe- there was no matter at all. That's why the Universe is generally studied in terms of its energy content, not its matter content.

[The Code]

Chris

Matter and energy... are the same thing....The Big Bang,, Was Energy Converting to Matter. I would like to learn the laws, that make the Above Fact

[Chris Peterson]

Matter and energy... are the same thing....The Big Bang,, Was Energy Converting to Matter. I would like to learn the laws, that make the Above Fact

E=mc^2

[The Code]

mark swain wrote:Matter and energy... are the same thing....The Big Bang,, Was Energy Converting to Matter. I would like to learn the laws, that make the Above Fact


E=mc^2

Matter and energy... are the same thing....The Big Bang,, Was Energy Converting to Matter. I would like to learn the laws, that make the Above Fact

E=mc^2


The law does not tell of the anti mater universe... which has to be fact

[Chris Peterson]

The law does not tell of the anti mater universe... which has to be fact

There is no antimatter Universe. There is the Universe, and it contains both matter and antimatter, and the law E=mc^2 applies equally to both.

[The Code]

There is no antimatter Universe.

Matter can not be destroyed... You may be correct at this point in time,, but this may not be true for all time. The anti matter came from some where.

[Chris Peterson]

Matter can not be destroyed... You may be correct at this point in time,, but this may not be true for all time. The anti matter came from some where.

Yeah, it came (and comes) from the same place any matter comes from. Energy. There's nothing special about antimatter- these are just a family of particles that fit nicely into the standard theory of particle physics. What isn't entirely certain is why the Universe settled into a state where most of the matter isn't "anti". But there are good theories to explain this. Basically, it is assumed that matter and antimatter were created in nearly equal amounts in the early Universe. Only a tiny imbalance between the two- something like one part in a billion- is necessary to explain the current dominance of matter over antimatter.

Of course, antimatter is being created and destroyed all the time, both naturally and in labs.

[The Code]

Matter can not be destroyed... You may be correct at this point in time,, but this may not be true for all time. The anti matter came from some where.

Yeah, it came (and comes) from the same place any matter comes from. Energy. There's nothing special about antimatter- these are just a family of particles that fit nicely into the standard theory of particle physics. What isn't entirely certain is why the Universe settled into a state where most of the matter isn't "anti". But there are good theories to explain this. Basically, it is assumed that matter and antimatter were created in nearly equal amounts in the early Universe. Only a tiny imbalance between the two- something like one part in a billion- is necessary to explain the current dominance of matter over antimatter.

Of course, antimatter is being created and destroyed all the time, both naturally and in labs.

Everything that was The Big bang,,, made its own lab... matter likes to take different forms... I must expect energy to take different forms also... thanks 4 your input Chris,,, I will return to this subject.

[harry]

G'day Mark

I would not put all my eggs on the Big Bang.

It's more important to know how things work rather than working with a Theoretical Model even though it is the standard model with many variations.

--------------------
Just sharing the reading, if I have posted this before, it's an oops. In addition I'm not trying to prove a point.

TOPICAL REVIEW: The gravitational-wave signature of core-collapse supernovae
Mar-09
http://adsabs.harvard.edu/abs/2009CQGra..26f3001O
http://adsabs.harvard.edu/cgi-bin/nph-d ... db_key=AST

We review the ensemble of anticipated gravitational-wave (GW) emission processes in stellar core collapse and postbounce core-collapse supernova evolution. We discuss recent progress in the modeling of these processes and summarize most recent GW signal estimates. In addition, we present new results on the GW emission from postbounce convective overturn and protoneutron star g-mode pulsations based on axisymmetric radiation-hydrodynamic calculations. Galactic core-collapse supernovae are very rare events, but within 3 5 Mpc from Earth, the rate jumps to 1 in ~2 years. Using the set of currently available theoretical gravitational waveforms, we compute upper-limit optimal signal-to-noise ratios based on current and advanced LIGO/GEO600/VIRGO noise curves for the recent SN 2008bk which exploded at ~3.9 Mpc. While initial LIGOs cannot detect GWs emitted by core-collapse events at such a distance, we find that advanced LIGO-class detectors could put significant upper limits on the GW emission strength for such events. We study the potential occurrence of the various GW emission processes in particular supernova explosion scenarios and argue that the GW signatures of neutrino-driven, magneto-rotational, and acoustically-driven core-collapse SNe may be mutually exclusive. We suggest that even initial LIGOs could distinguish these explosion mechanisms based on the detection (or non-detection) of GWs from a galactic core-collapse supernova.

[harry]

G'day caunuk100

That post was in relation to a comment in the previous post.

As for not related to Supernova think again.

Detection is the first step in science.

Please do not use silly statements like

Interesting but not particularly relevant to supernovae. Heaven help anyone who wants to use this forum to research a topic!! Perhaps a moderator will move this to a new thread.

Where do you think cosmic rays come from?

[canuck100]

Where do you think cosmic rays come from?

If you take the trouble to visit the AMS Experiment Web SIte, at http://cyclo.mit.edu/~bmonreal/and read their objectives you will see why I said that your post had little to do with supernovae.

In general, AMS is trying to study the sources of cosmic rays. These sources include ordinary things like stars and supernovae, as well as (perhaps!) exotica like quark stars, dark-matter annihilations, and galaxies made entirely of antimatter.

The web site explicitly states that the production of cosmic rays by supernovae is well understood and that this experiment is designed to research areas that are far less well understood.
They then list their scientific objectives, most of which have primarily to do with studying cosmic rays from exotic sources. The web site clearly lists nine scientific goals:

• 1. Antimatter--detection of anti-helium nuclei,
  2. Dark matter--detection of high energy positrons resulting from neutralino collisions,
  3. Strange quark matter - detection of high mass particles with low charge/mass ratios 4. Age of cosmic rays - detection of Beryllium-10
  5. Find "interesting" sources emitting ultra high energy gamma rays,
  6. Research earth's particle environment created by cosmic ray bombardment of the atmosphere,
  7. Microquasars - detection of anomalies in cosmic ray spectrum,
  8. Microscopic black holes - detection of low-energy antiprotons and antideuterons
  9. Search for any unpredicted or unexpected result.

In a very broad sense, I suppose the AMS Experiment is related to supernovae but in a broad sense the advancement of physics in any one area advances our understanding in other areas.
However, someone searching this forum for information and links that would further their understanding of supernovae would not be assisted by links to the AMS Experiment.
In your very first post on this thread you stated

Supernova, what do we really know about its formation. I'm going to post papers written on the subject rather than giving an opinion.

The AMS Experiment is not designed to investigate the formation of supernovae.

[harry]

G'day canuck100

No trouble in reading

http://cyclo.mit.edu/~bmonreal/

Thank you

I think you read my post out of context. Oh!!! well does not matter.

For some WIKI explains Supernova particularly, although limited in info.

http://en.wikipedia.org/wiki/Supernova

Core collapse
See also: Gravitational collapse
The core collapses in on itself with velocities reaching 70,000 km/s (0.23c),[59] resulting in a rapid increase in temperature and density. The energy loss processes operating in the core cease to be in equilibrium. Through photodisintegration, gamma rays decompose iron into helium nuclei and free neutrons, absorbing energy, whilst electrons and protons merge via electron capture, producing neutrons and electron neutrinos which escape.

In a typical Type II supernova, the newly formed neutron core has an initial temperature of about 100 billion kelvin (100 GK); 6000 times the temperature of the sun's core. Much of this thermal energy must be shed for a stable neutron star to form (otherwise the neutrons would "boil away"), and this is accomplished by a further release of neutrinos.[60] These 'thermal' neutrinos form as neutrino-antineutrino pairs of all flavors, and total several times the number of electron-capture neutrinos.[61] About 1046 joules of gravitational energy—approximately 10% of the star's rest mass—is converted into a ten-second burst of neutrinos; the main output of the event.[54][62] These carry away energy from the core and accelerate the collapse, while some neutrinos may be later absorbed by the star's outer layers to provide energy to the supernova explosion.[63]

The inner core eventually reaches typically 30 km diameter,[54] and a density comparable to that of an atomic nucleus, and further collapse is abruptly stopped by strong force interactions and by degeneracy pressure of neutrons. The infalling matter, suddenly halted, rebounds, producing a shock wave that propagates outward. Computer simulations indicate that this expanding shock does not directly cause the supernova explosion;[54] rather, it stalls within milliseconds[64] in the outer core as energy is lost through the dissociation of heavy elements, and a process that is not clearly understood is necessary to allow the outer layers of the core to reabsorb around 1044 joules[nb 3] (1 foe) of energy, producing the visible explosion.[65] Current research focuses upon a combination of neutrino reheating, rotational and magnetic effects as the basis for this process.[54]

When the progenitor star is below about 20 solar masses (depending on the strength of the explosion and the amount of material that falls back), the degenerate remnant of a core collapse is a neutron star.[59] Above this mass the remnant collapses to form a black hole.[56][66] (This type of collapse is one of many candidate explanations for gamma ray bursts—producing a large burst of gamma rays through a still theoretical hypernova explosion.)[67] The theoretical limiting mass for this type of core collapse scenario was estimated around 40–50 solar masses.

Above 50 solar masses, stars were believed to collapse directly into a black hole without forming a supernova explosion,[68] although uncertainties in models of supernova collapse make accurate calculation of these limits difficult. In fact recent evidence has shown stars in the range of about 140–250 solar masses, with a relatively low proportion of elements more massive than helium, may be capable of forming pair-instability supernovae without leaving behind a black hole remnant. This rare type of supernova is formed by an alternate mechanism (partially analogous to that of Type Ia explosions) that does not require an iron core. An example is the Type II supernova SN 2006gy, with an estimated 150 solar masses, that demonstrated the explosion of such a massive star differed fundamentally from previous theoretical predictions.[69][70]

[bystander]

Let us stay on the topic of supernovae. Further digression will result in this topic being closed.

[harry]

G'day

What ever you say Bystander.

Is it that simple that we have two main types of supernova.

and the way we detect transient forms is just amazing.

During a supernova matter changes phase and is called a transient, not only that we expect a gravitational wave to occur and to be detected ( see earlier posts).

http://arxiv.org/abs/0909.0631
Optical follow-up of high-energy neutrinos detected by IceCube

Authors: A. Franckowiak, C. Akerlof, D. F. Cowen, M. Kowalski, R. Lehmann, T. Schmidt, F. Yuan, for the IceCube collaboration, for the ROTSE collaboration
(Submitted on 3 Sep 2009)

Abstract: Three-quarters of the 1 cubic kilometer neutrino telescope IceCube is currently taking data. Current models predict high-energy neutrino emission from transient objects like supernovae (SNe) and gammaray bursts (GRBs). To increase the sensitivity to such transient objects we have set up an optical follow-up program that triggers optical observations on multiplets of high-energy muon-neutrinos. We define multiplets as a minimum of two muon-neutrinos from the same direction (within 4 deg) that arrive within a 100 s time window. When this happens, an alert is issued to the four ROTSE-III telescopes, which immediately observe the corresponding region in the sky. Image subtraction is applied to the optical data to find transient objects. In addition, neutrino multiplets are investigated online for temporal and directional coincidence with gamma-ray satellite observations issued over the Gamma-Ray Burst Coordinate Network. An overview of the full program is given, from the online selection of neutrino events to the automated follow-up, and the resulting sensitivity to transient neutrino sources is presented for the first time.

[harry]

G'day

I'm taking Makc advice, I'm off on a holiday.

[canuck100]

In the thread discussing dark matter and dark energy, you commented:

You said that the BBT is widely accepted means very little to me. I have seen Standard models in the past fall by the side and through History people just follow the MOB.
. . .
The redshift is one data that is coming under fire due to the lack of info on the intrinsic properties of supernovas.

At http://www.sciencedaily.com/releases/20 ... 173322.htm a May 2009 article reports:

Cosmology's Best Standard Candles Get Even Better
. . .
Members of the international Nearby Supernova Factory (SNfactory), a collaboration among the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, a consortium of French laboratories, and Yale University, have found a new technique that establishes the intrinsic brightness of Type Ia supernovae more accurately than ever before. These exploding stars are the best standard candles for measuring cosmic distances, the tools that made the discovery of dark energy possible.
. . .
The new brightness-ratio correction appears to hold no matter what the supernova’s age or metallicity (mix of elements), its type of host galaxy, or how much it has been dimmed by intervening dust.

and at http://www.sciencedaily.com/releases/20 ... 143934.htm an August 2009 article reports:

Variability Of Type 1a Supernovae Has Implications For Dark Energy Studies
. . . a new study published this week in Nature reveals sources of variability in type 1a supernovae that will have to be taken into account if astronomers are to use them for more precise measurements in the future
. . .
In order to use type 1a supernovae for very sensitive distance measurements, better corrections for differences in brightness will have to be made.
. . .
Much of the diversity observed is due to chaotic processes and resulting asymmetry which are not expected to create systemic errors. Corrections can also be developed for differences in chemical composition.
. . .
"Since we are beginning to understand how type 1a supernovae work from first principles, these models can be used to refine our distance estimates and make measurements of the expansion rate of the universe more precise," Woosley said.

Neither of these two recent, credible articles suggest that redshift data gleaned from type 1a supernovae is under attack.

Furthermore, demonstrating that they are not held sway by a "mob" mentality, some of these same researchers report on their areas of concern and the research they are undertaking to address these concerns at
http://www.sciencedaily.com/releases/20 ... 160108.htm in September 2009

Computer Code Gives Astrophysicists First Full Simulation Of Star's Final Hours
The precise conditions inside a white dwarf star in the hours leading up to its explosive end as a Type Ia supernova are one of the mysteries confronting astrophysicists studying these massive stellar explosions. But now, a team of researchers, composed of three applied mathematicians at the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory and two astrophysicists, has created the first full-star simulation of the hours preceding the largest thermonuclear explosions in the universe.
. . .
a team of researchers, composed of three applied mathematicians at the U.S. Department of Energy's (DOE) Lawrence Berkeley National Laboratory and two astrophysicists, has created the first full-star simulation of the hours preceding the largest thermonuclear explosions in the universe
. . . But what if Type Ia supernovae have not always exploded in the same way? What if they aren't standard? . . .
The problem is that astrophysicists still don't know exactly how a star of this type explodes. Over the years, several simulations have tried to answer the problem, but the traditional methods and available supercomputing power haven't been up to the task.
. . .
Almgren and Nonaka caution against reading too much into results from a single calculation. While the work described in this paper—their fourth in the Astrophysical Journal about MAESTRO—is an important step towards understanding this problem, more work is needed to be confident in the results. "We need to explore the effects of rotation, of resolution, and of different initial compositions of the star," says Zingale. "But with MAESTRO now up and running on today's fastest supercomputers, we are well on our way."

[bystander]

HEAPOW: The Shape of Things that Were (2009 Dec 21)

What's the difference between the two dead stars above? They both look like bright glowing balls of X-ray emitting gas, enormous nebulae produced by the explosion of stars that reached the end of their lives. One produced by the core collapse of a massive star that ran out of fuel, the other produced by the deflagration of the burnt-out core of a low mass star. Which is which? Hard to tell, but careful analysis of X-ray images obtained by the Chandra X-ray Observatory of 17 supernova remnants in the Milky Way and the Large Magellanic, like those above, showed subtle but distinct differences between the two types of supernova. In the case of the core collapse supernovae, the remnant left behind is significanly more asymmetric nebulae than the other type. There was one oddball in the study - a remnant that had the chemical abundances of a deflagration, but the shape of a core-collapse.

Supernova Explosions Stay In Shape (CXC 2009 Dec 17) Press Release Photos

• A new study of supernova remnants allowed scientists to categorize the explosion that created them based on their shape
  
  Supernovas that come from thermonuclear explosion on white dwarfs (known as Type Ia) produce very symmetric remnants
  
  Another type, created when a very massive star collapses, results in more asymmetrically shaped remnants

[harry]

G'day bystander

You may find this link interesting.

Please do not ask me if I have read it or not.


Typing Supernova Remnants Using X-ray Line Emission Morphologies
http://arxiv.org/abs/0910.3208
Authors: Laura A. Lopez (UCSC), Enrico Ramirez-Ruiz (UCSC), Carles Badenes (Princeton), Daniela Huppenkothen (Amsterdam), Tesla E. Jeltema (UCO/Lick Observatories), David A. Pooley (Wisconsin)
(Submitted on 19 Oct 2009)

Abstract: We present a new observational method to type the explosions of young supernova remnants (SNRs). By measuring the morphology of the Chandra X-ray line emission in seventeen Galactic and Large Magellanic Cloud SNRs with a multipole expansion analysis (using power ratios), we find that the core-collapse SNRs are statistically more asymmetric than the Type Ia SNRs. We show that the two classes of supernovae can be separated naturally using this technique because X-ray line morphologies reflect the distinct explosion mechanisms and structure of the circumstellar material. These findings are consistent with recent spectropolarimetry results showing that core-collapse SNe are intrinsically more asymmetric.