Starship Asterisk*

Chris Peterson wrote:

dougettinger wrote:Do astronomers have actual evidence of a binary pair where one was known to have been a supernova either Type Ia or Type II due to its remnants ? The Necklace Nebula is obviously evidence for a binary pair after one entered the red giant phase.

Yes. This one is very cool because it's such a historical supernova.

APOD Robot wrote: The Necklace Nebula

Explanation: The small constellation Sagitta sports this large piece of cosmic jewelry, dubbed the Necklace Nebula.

Chris Peterson wrote:

dougettinger wrote:
Do astronomers have actual evidence of a binary pair where one was known to have been a supernova either Type Ia or Type II due to its remnants ? The Necklace Nebula is obviously evidence for a binary pair after one entered the red giant phase.

Yes. This one is very cool because it's such a historical supernova.

http://www.ing.iac.es/PR/AR2005/chap1.html wrote:

Centre of Tycho's supernova remnant. The star marked as 'G' is identified as the companion G0–G2 star of Tycho Brahe´s 1572 supernova. Since 1572, Tycho G has moved 2.6 arcseconds south.

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The Companion Star to Type Ia Tycho Brahe's 1572 Supernova

<<The brightness of type Ia supernovae, and their homogeneity as a class, makes them powerful tools in cosmology, yet little is known about the progenitor systems of these explosions. They are thought to arise when a white dwarf accretes matter from a companion star, is compressed and undergoes a thermonuclear explosion. Unless the companion star is another white dwarf (in which case it should be destroyed by the mass-transfer process itself), it should survive and show distinguishing properties.

Tycho’s supernova is one of only two type Ia supernovae observed in our Galaxy, and so provides an opportunity to address observationally the identification of the surviving companion.

A team of astronomers carried out an imaging and spectroscopic survey using ISIS, UES and the Auxiliary Camera on the WHT of the central region of Tycho's supernova remnant, around the position of the explosion. The analysis of the data excluded red giants as the mass donor of the exploding white dwarf. However, they found a type G0–G2 star, similar to our Sun in surface temperature and luminosity (but lower surface gravity), moving at more than three times the mean velocity of the stars at that distance, which they claim to be the surviving companion of the supernova.>>

http://www.riggenho.com/tycoGpro.htm wrote:

Building a 136 km/s Tycho “G” Pro

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Building a Tyco “G” Pro -- a hot TycoPro with traction magnets and other performance mods...! by Terry Flynn

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dougettinger wrote:Do astronomers have actual evidence of a binary pair where one was known to have been a supernova either Type Ia or Type II due to its remnants ? The Necklace Nebula is obviously evidence for a binary pair after one entered the red giant phase.

dougettinger wrote:Thanks for your simple but very adequate reply. Since I have you in this frame of mind, what do you suppose happens to a neighboring binary when the progenitor is a supernova ? Is the star swept away in the blast? Is it destroyed ? Or does it maintain some orbit and keep fusing ?

dougettinger wrote:I did not make myself well understood. When the progenitor star begins to shed its outer layers, why does not the neighboring binary capture some or all of these materials being shed ?

dougettinger wrote:What is owlice reference in the following submission ?

dougettinger wrote:A white dwarf may draw material from a close binary neighbor.
When one binary star dies why is not its material captured by the other binary star when it sheds its outer layers ?

Chris Peterson wrote:

dougettinger wrote:A white dwarrf may draw material from a close binary neighbor. When one binary star dies why is not its material captured by the other binary star when it sheds its outer layers ?

Any star can capture material from a close binary. In this case, it is unlikely that the progenitor has had enough time to become a white dwarf yet. It is probably still fusing hydrogen. Even if hydrogen fusion has stopped, the star is probably still in the process of consolidating into a white dwarf.

I'm not positive, but I suspect that the careful photometry involved in determining that there is actually a binary progenitor would have detected signs of material falling inwards in an accretion disc.

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dougettinger wrote:A white dwarrf may draw material from a close binary neighbor. When one binary star dies why is not its material captured by the other binary star when it sheds its outer layers ?

mpharo wrote:This little nebula has at least 13 orange stars in a circle with a star at the center. The necklace has a light blue surrounding and a bright green glow around it's small circumference. I like that contrast of colors. I wonder what the two dark blue circles are in the center.

harry wrote:The papers that I posted are mainstream and are not backyard papers.

harry wrote:The papers that I posted are mainstream and are not backyard papers.
...
Then I would advise a bit of research. Maybe arXiv or NASA ADS

Neither of the papers Harry listed are particularly relevant to your questions. But I think your understanding is pretty good, as outlined above. The key concept is that the star has a powerful magnetic field, and the twisting of this field- especially by a rapidly rotating star- is what fundamentally drives jet formation. It has nothing to do with matter in any sort of exotic state.

Chris Peterson wrote:

dougettinger wrote:G'day, Harry. I am trying to better understand the dipolar jets of both protostars and dying stars. What is common to both is that material falls inward mostly by spinning plasma in the equatorial regions. The particles are being pushed together but are resisting due to their inherent magnetic properties. Time is needed to arrange the particles into more compact arrangements, but due to irregular densities many magnetized particles pop out at the center similar to squeezing a balloon around its girth. Until enough time is acquired to re-arrange the particles into higher compaction (elements with higher atomic numbers), the particles especially electrons are ejected at both poles of the imploding star by both pressure and electrical energy.

These are words that I can understand. Is this concept close to what you stated?

Neither of the papers Harry listed are particularly relevant to your questions. But I think your understanding is pretty good, as outlined above. The key concept is that the star has a powerful magnetic field, and the twisting of this field- especially by a rapidly rotating star- is what fundamentally drives jet formation. It has nothing to do with matter in any sort of exotic state.

I am still anxious to know what kind of stars were left in the aftermath of the creation of the Necklace Nebula (?)

Presumably, the progenitor star is still undergoing hydrogen fusion in its outer shell, or possibly has just begun cooling and is heading towards its white dwarf phase. The second star is unlikely to have changed from whatever it was before the progenitor star shed its envelope.

Chris Peterson wrote:Neither of the papers Harry listed are particularly relevant to your questions.

dougettinger wrote:G'day, Harry. I am trying to better understand the dipolar jets of both protostars and dying stars. What is common to both is that material falls inward mostly by spinning plasma in the equatorial regions. The particles are being pushed together but are resisting due to their inherent magnetic properties. Time is needed to arrange the particles into more compact arrangements, but due to irregular densities many magnetized particles pop out at the center similar to squeezing a balloon around its girth. Until enough time is acquired to re-arrange the particles into higher compaction (elements with higher atomic numbers), the particles especially electrons are ejected at both poles of the imploding star by both pressure and electrical energy.

These are words that I can understand. Is this concept close to what you stated?

I am still anxious to know what kind of stars were left in the aftermath of the creation of the Necklace Nebula (?)

harry wrote:G'day

Supernova is where a star explodes completely and a Nova is where the solar envelope is ejected to some degree.

Doug asked the questiion

What possible mechanism causes polar jets in the case of the Necklace Nebula or a dying star ? These jets, according to the article, occurred 5000 years prior to the nebula cloud being created.

What are the possible candidate types for the two stars orbiting in less than two days ? Would not the lesser mass body be eaten by the larger mass ? Could a neutron star feed on a white dwarf ?

The power for such jets lies in the dynamic properties of Nuclear phase transitions within compact Nuclear matter and their ability to form spontaneous dipolar jets with enough stability to form jets that may go for light years.

What possible mechanism causes polar jets in the case of the Necklace Nebula or a dying star ? These jets, according to the article, occurred 5000 years prior to the nebula cloud being created.

What are the possible candidate types for the two stars orbiting in less than two days ? Would not the lesser mass body be eaten by the larger mass ? Could a neutron star feed on a white dwarf ?

Abstract: The Galaxy Ultraviolet Explorer (GALEX) satellite has recently shown the presence of an extended, outer ring studded with UV-bright knots surrounding the lenticular galaxy NGC 4262. Such a structure---not detected in the optical---is coupled with a ring of atomic (HI) gas. We want to show that both star-forming and HI rings surrounding this SB0 galaxy share the same radial distance from the galaxy center and spatial orientation. We want also to model the kinematics of the ring(s) and of the galaxy body. We make use of archive FUV and NUV GALEX data plus HI observations from the literature. We confirm that the UV-bright and atomic gas rings of NGC 4262 have the same extent and projected spatial orientation. Their kinematics is not coupled with that of the galaxy stars. It is possible that NGC 4262 has undergone a major gas stripping event in the past which gave origin to the present "necklace" of UV-bright knots.

Chris Peterson wrote:

dougettinger wrote:I am still a little puzzled how one tells the difference between a supernova remnant and a planetary nebula that have occurred thousands of years ago.

Well, the easiest way is probably just to look at the velocity of the ejected material. Planetary nebulas have expansion rates on the order of a few tens of km/s. Supernova remnants have expansion rates on the order of 1000 km/s. The velocity of the expansion is a primary measurement, made by looking at the Doppler shift of specific emission lines at different parts of the structures.