Stellar Remnants

[harrycostas]

Re: Betelgeuse is one strange place

G'day from the land of ozzzz

Does a supernova or a nova spell the end of a star or just a phase change in it's evolution?

 

[MeteorWayne]

For a Nova, it's just a phase in it's evolution. For a supernova, it depends on the mass. Some are blasted to bits and spread through space, others are left with a black hole or other dense object behind.

 

[harrycostas]

Re: Betelgeuse is one strange place

G'day

Even a remnant compact object would have a gravity sink that would attract matter from the nebulae or merge with a star and or waiting for the right moment to form a new solar envelope.

 

[MeteorWayne]

Re: Betelgeuse is one strange place

Attract matter from what nebula?
You really should educate youself on stellar evolution.

Free mentor adviace

 

[harrycostas]

Re: Betelgeuse is one strange place

G'day MeteorWayne

With due respect, if you knew anything about stellar evolution and Nebulae you would have understood what I said.

I keep on educating myself on the topics regardless.

When a Star ejects its solar envelope in many cases a compact remnant is left behind acting as a gravity sink. The ejected matter forming the nebula is attracted back in other cases it may attract other matter from other Nebula or even merge with another Star.

The force that ejects matter away is found in the core of the old Sun that creates jets that are able to eject matter away in the form of exploding bubbles or jet streams, yes other surface jets do form but! they do not have the magnetic drive compared to the core mass.

http://chandra.harvard.edu/photo/2006/pne/
Mz 3:
Planetary Nebulas - Fast Winds from Dying Stars

NGC 6543:
The Cat's Eye Nebula Redux
http://chandra.harvard.edu/photo/2008/catseye/

http://antwrp.gsfc.nasa.gov/apod/ap080617.html
APOD: 2008 June 17- Eta Carinae and the Homunculus Nebula

 

[MeteorWayne]

Re: Betelgeuse is one strange place

harry,
First of all this discussion is pretty unrelated to the current evolution of Betelgeuse, which is the subject of the topic.

Perhaps the subject of what happens to a compact stellar remnant would be best in it's own thread?

Once again, I don't understand the point of your links. Is it that after the core is exposed the stellar wind increases to millions of miles (or km) per hour and the material is ejected into deep space, far from the remnant? So what is left surround the remnant is far less dense than the rest of interstellar space? So that the gravity sink (which is of couse far less massive than the star originally was due to the ejected mass) has little or nothing to collect, and whatever is there is moving away at a higher velocity that the escape velocity of the remnant?

Eventually, sure it may attract some gas from another area, but so what? A stellar remnant is far too small (mass wise)to collect a significant amount of material...the nebula from which even a solar mass star forms begins with many times the mass of the final star so can collect gas; a tiny remnant doesn't have enough.

As for colliding with another star, do you have any idea how unlikely that is? It may have happened (for such tiny remnants) a handful of times in the entire history of the Milky way. Or once. Or never, since it's so unlikely.

And what is the point? Are you saying the star is reborn?

As for this statemnt, can you try again? I have no idea as to the point you are trying to make.

"The force that ejects matter away is found in the core of the old Sun that creates jets that are able to eject matter away in the form of exploding bubbles or jet streams, yes other surface jets do form but! they do not have the magnetic drive compared to the core mass."

Wayne

 

[harrycostas]

G'day MeteorWayne

Where did you get the idea that supernova remnants are too small?

Where do you think Neutron Stars and exotic stars such as Quarks and so called stellar black holes come from?

And as for a gravity sink even the smallest of remnant is able to form a seed so that nebula dust clusters on.

 

[MeteorWayne]

If you would reread what I said, I said they don't have enough mass, not that they were too small. Perhaps you don't understand the difference?

I know where they come from; what I am saying is that they are not massive enough to collect any significant mass from the surrounding material which has been blasted billions of miles away.

And again, I ask what the heck is your point? Are you saying they can collect enough mass to be resurrected as stars? If so, you are in the deep depths of foolishness..

Please post your obligatory unrelated links now....

 

[harrycostas]

G'day MeteorWayne

You said

I know where they come from; what I am saying is that they are not massive enough to collect any significant mass from the surrounding material which has been blasted billions of miles away.

And again, I ask what the heck is your point? Are you saying they can collect enough mass to be resurrected as stars? If so, you are in the deep depths of foolishness..

I understand the difference between size and mass, but you do not undestand the scope of the information relating to star formation and rejuvination and phase changes.

and as for significant mass, please provide some form of back up for your claim.

 

[ramparts]

G'day Harry! Harry, what exactly are you claiming?

 

[harrycostas]

G'day ramparts

Star formation is a very complicated process and there are various ways they may originate and rejuvinate.

Supernova remnants (not all) usually are quite compact. The reason for this is explained by how the supernova is formed. The supernova, its shape and process is dependent on the magnetic fields and their reconnection, which are controlled by a compact core.

 

[ramparts]

Well, what do you mean by there being various ways stars can form and "rejuvenate"? I know of one way of stars forming - gas in a cloud collapses on itself - but perhaps we can see various ways within that

 

[harrycostas]

G'day

G'day ramparts, please do not limit yourself to what you only know, read a bit mor on the phases of star formation, jet formation and the seeding of stars. The formation of stars from condensation of clouds maybe an option, but the probability of it occuring over the probability of the dust clustering to existing gravity sinks is quite small, given the motions within a galaxy and the surrounding stars.

I did not want to post any more links, but I cannot help myself to share the reading. Compact matter is one of the key issues in cosmology and over the last decade or so there has been a huge move to a greater understanding.

http://arxiv.org/abs/astro-ph/0312328
Revealing the obscured supernova remnant Kes 32 with Chandra

Authors: Jacco Vink (Columbia University and SRON National Institute for Space Research, The Netherlands)
(Submitted on 12 Dec 2003)

Abstract: I report here on the analysis and interpretation of a Chandra observation of the supernova remnant Kes 32. Kes 32 is rather weak in X-rays due to a large interstellar absorption, which is found to be ~4E22 cm^-2, larger than previously reported. Spectral analysis indicates that the ionization age of this object is very young, with n_e t ~ 4E9 cm^-3s, and a temperature of kT_e ~ 1 keV. The X-ray emission peaks at a smaller radius than in the radio. The low ionization age suggests that Kes 32 is a young remnant. However, a young age is in contradiction with the relatively large apparent size, which indicates an age of several thousand years, instead of a few hundred years. This problem is discussed in connection with Kes 32's unknown distance and its possible association with the Norma galactic arm.

http://arxiv.org/abs/astro-ph/0311526
Central Compact Objects in Supernova Remnants

Authors: George G. Pavlov, Divas Sanwal, Marcus A. Teter (Pennsylvania State University)
(Submitted on 23 Nov 2003)

Abstract: There are point-like sources in central regions of several supernova remnants which have not been detected outside the X-ray range. The X-ray spectra of these Central Compact Objects (CCOs) have thermal components with blackbody temperatures of 0.2-0.5 keV and characteristic sizes of 0.3-3 km. Most likely, the CCOs are neutron stars born in supernova explosions. We overview their observational properties, emphasizing the Chandra data, and compare them with magnetars.

 

[ramparts]

Oh! By "stars" you mean compact objects like neutron stars? In that case, yes, it's very true those form from supernovae

I'm guessing you posted the second paper to show that compact objects are found in supernova remnants (yes, I'm aware, thanks ), but I'm not sure why you post the first paper, which seems like a pretty routine observational paper about some particular (not very special) object.

 

[harrycostas]

G'day ramparts

If you do not realize the importance of the first paper then read it again and then tell me.

Before I post anymore links, I should ask:

Do you want to read more or am I wasting my time, if so,,,,,,It's OK?

oops one more

http://arxiv.org/abs/astro-ph/0508243
Chandra X-ray Observation of a Mature Cloud-Shock Interaction in the Bright Eastern Knot Region of Puppis A

Authors: Una Hwang, Kathryn A. Flanagan, Robert Petre
(Submitted on 10 Aug 2005)

Abstract: We present Chandra X-ray images and spectra of the most prominent cloud-shock interaction region in the Puppis A supernova remnant. The Bright Eastern Knot (BEK) has two main morphological components: (1) a bright compact knot that lies directly behind the apex of an indentation in the eastern X-ray boundary and (2) lying 1' westward behind the shock, a curved vertical structure (bar) that is separated from a smaller bright cloud (cap) by faint diffuse emission. Based on hardness images and spectra, we identify the bar and cap as a single shocked interstellar cloud. Its morphology strongly resembles the ``voided sphere'' structures seen at late times in Klein et al.'s experimental simulations of cloud-shock interactions, when the crushing of the cloud by shear instabilities is well underway. We infer an interaction time of roughly 3 cloud-crushing timescales, which translates to 2000-4000 years, based on the X-ray temperature, physical size, and estimated expansion of the shocked cloud. This is the first X-ray identified example of a cloud-shock interaction in this advanced phase. Closer to the shock front, the X-ray emission of the compact knot in the eastern part of the BEK region implies a recent interaction with relatively denser gas, some of which lies in front of the remnant. The complex spatial relationship of the X-ray emission of the compact knot to optical [O III] emission suggests that there are multiple cloud interactions occurring along the line of sight.

 

[MeteorWayne]

And none of the 3 links you posted, as usual, have anything to do with what you appear to be suggesting, which if I am guessing correctly (since you refuse to answer the direct question you've been asked several times now) is that matter falls back on the remnant.

None of them even vaguely suggest that.

 

[ramparts]

Harry, as in another thread, this is just a matter of common courtesy - if you're going to post information like a paper, please tell us why. Otherwise there's just no point.

 

[harrycostas]

G'day

To understand the papers is to understand the point.

That was the last paper.

 

[MeteorWayne]

Then it must be your last post,... since you seem to not answer direct questions, and only post papers that are irrelevant or refute the point you are trying to make....

 

[harrycostas]

G'day MeteorWayne

If there was a positive response I would go out of my way to explain. I do not want to waste my time.

 

[ramparts]

Harry, what do you mean "a positive response"? We're trying to engage with your ideas here, but it's hard to do that when we're so frequently met with answers like "figure it out yourself" or "do some research." If you can spend time posting your ideas, you need to be ready to spend time explaining them.

 

[MeteorWayne]

G'day MeteorWayne

If there was a positive response I would go out of my way to explain. I do not want to waste my time.

What would you consider a positive response? Someone foolish enough to believe that because you post unrelated papers it has some meaning? Someone who believes that when you post links that refute the points you allegedly are trying to make consider them evidence supporting your views?

Sorry my friend, we're smarter than that here.

MW

 

[harrycostas]

G'day MeteorWayne

You have missed the point, the point is science discussion, that is the positive.

What is the point of discussion when all that you are interested is being right ?

This is not science.

 

[silylene]

Haryy, you have me confused on the question and/or point that you are making. Let me rephrase your posts, as far as I can tell (I hope I am not misstating you):
-After a supernova, a black hole object can remain
-A black hole's gravitation can pull gases from surrounding environs back onto itself
-If enough gases got pulled back to the hole, then the star can be rejuvinated or reborn

Unfortunately I think you are wrong:
- In almost all cases there is not enough gases left in the environ after a supernova (b/c everything to blasted away) to infall back.
- In the unlikely case that a black hole does move into a gas-rich region, yes I agree, lots of gas can infall. (Unlikely since there are much fewer substantial clouds of gas lying around in our matured universe.)
- However, if substantial amounts of new gas infalls into the black hole, all you get is a bigger black hole with a couple of polar jets, but never a reborn star.

 

[kg]

I think you have to remember that a star remnent is very different than the core of a star. It so happens that gas falling onto the surface of a remnent is somewhat common but the "dead" star does not get rejuvinated. Because the gravity at the surface of a white dwarfe or neutron star is so intense it tends to explode when enough mass is dumped onto it. This usually happens with close binary stars when one of the pair matures first then syphons gas from the surface or the remaining star.
http://en.wikipedia.org/wiki/Nova