Starship Asterisk*

Ann wrote:
I had never seen the shock front of Cygnus X-1 before. How fascinating!

https://en.wikipedia.org/wiki/Cygnus_X-1 wrote:

[b][color=#0000FF]On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box [between the Tulip nebula & Eta Cygni]. An artist's illustration on the right depicts the Cygnus X-1 system.[/color][/b]

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<<Cygnus X-1 (abbreviated Cyg X-1) is a galactic X-ray source in the constellation Cygnus, and the first such source widely accepted to be a black hole. It was discovered in 1964 during a rocket flight and is one of the strongest X-ray sources seen from Earth, producing a peak X-ray flux density of 2.3×10⁻²³ Wm⁻² Hz⁻¹ (2.3×10³ Jansky). The compact object is now estimated to have a mass about 14.8 times the mass of the Sun and has been shown to be too small to be any known kind of normal star, or other likely object besides a black hole. If so, the radius of its event horizon is about 44 km.

Cygnus X-1 belongs to a high-mass X-ray binary system, located about 6070 light years from the Sun, that includes a blue supergiant variable star designated HDE 226868 which it orbits at about 0.2 AU, or 20% of the distance from the Earth to the Sun. A stellar wind from the star provides material for an accretion disk around the X-ray source. Matter in the inner disk is heated to millions of degrees, generating the observed X-rays. A pair of jets, arranged perpendicular to the disk, are carrying part of the energy of the infalling material away into interstellar space.

The Cygnus X-1 jets are inefficient radiators and so release only a small proportion of their energy in the electromagnetic spectrum. That is, they appear "dark". The estimated angle of the jets to the line of sight is 30° and they may be precessing. One of the jets is colliding with a relatively dense part of the interstellar medium (ISM), forming an energized ring that can be detected by its radio emission. This collision appears to be forming a nebula that has been observed in the optical wavelengths. To produce this nebula, the jet must have an estimated average power of (9±5)×10²⁹ W. This is more than 1,000 times the power emitted by the Sun. There is no corresponding ring in the opposite direction because that jet is facing a lower density region of the ISM.>>

E Fish wrote:I didn't know that Cygnus X-1 was called a microquasar. I thought it was just a black hole. Is that a new designation?

https://en.wikipedia.org/wiki/Cygnus_X-1 wrote:

[b][color=#0000FF]On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box [between the Tulip nebula & Eta Cygni]. An artist's illustration on the right depicts the Cygnus X-1 system.[/color][/b]

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E Fish wrote:I didn't know that Cygnus X-1 was called a microquasar. I thought it was just a black hole. Is that a new designation?

De58te wrote:

E Fish wrote:I didn't know that Cygnus X-1 was called a microquasar. I thought it was just a black hole. Is that a new designation?

Cygnus X-1 is a stellar-mass black hole, as the linked site says.
A microquasar is when there is a companion star and material is pulled into the accretion disc at temperatures in millions of degrees that they produce X-rays. The microquasar is this X-ray emitting accretion disc that is surrounding the black hole, not the black hole proper.

rstevenson wrote:

https://en.wikipedia.org/wiki/Cygnus_X-1 wrote:

[b][color=#0000FF]On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box [between the Tulip nebula & Eta Cygni]. An artist's illustration on the right depicts the Cygnus X-1 system.[/color][/b]

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In the artist's illustration above, there is a small white point of light where the material from the blue giant blends into the orange stream orbiting the black hole. Since this is an illustration, it seems rather unlikely that the white spot is a background star. But what could it represent? Does the stellar material reach a density sufficient to make it glow before it is torn apart again by the black hole?

Rob

https://en.wikipedia.org/wiki/W50_(nebula) wrote:

[b][color=#008000]Radio image of supernova remnant W50 in green[/color], [color=#FF0000]infrared background in red.[/color] [color=#008000]NRAO/AUI/NSF, K. Golap, M. Goss[/color]; [color=#FF0000]NASA’s Wide Field Survey Explorer (WISE)[/color][/b]

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<<W50 or SNR G039.7-02.0, once referred to as the Manatee Nebula, is a Supernova remnant located in the constellation Aquila, about 18,000 light years away. In its centre lies the micro-quasar SS433, whose jets are distorting the remnant's shell. Most likely W50 and SS 433 are related objects, remnants from a supernova which occurred about 20,000 years ago.>>

Ann wrote:

rstevenson wrote: In the artist's illustration above, there is a small white point of light where the material from the blue giant blends into the orange stream orbiting the black hole. Since this is an illustration, it seems rather unlikely that the white spot is a background star. But what could it represent? Does the stellar material reach a density sufficient to make it glow before it is torn apart again by the black hole?

Rob

I'm just guessing, mind you. Could that perhaps be the spot where gas flowing from the blue giant companion hits the swirling accretion disk, so that a lot of energy is produced in that small spot?

Ann

Ann wrote:What a nice picture! And Ivan Eder is one of my favorite astrophotographers.

I had never seen the shock front of Cygnus X-1 before. How fascinating!

Ann

MarkBour wrote:

Ann wrote:

rstevenson wrote:
In the artist's illustration above, there is a small white point of light where the material from the blue giant blends into the orange stream orbiting the black hole. [What] could it represent? Does the stellar material reach a density sufficient to make it glow before it is torn apart again by the black hole?

Could that perhaps be the spot where gas flowing from the blue giant companion hits the swirling accretion disk, so that a lot of energy is produced in that small spot?

[I'm not trying to create a dispute about the reference to this system (Cygnus X-1), but the article on the Chandra site that I think Art (neufer) got the 2-part illustration from, has as its right panel, an illustration that was actually an earlier APOD: 20 Nov 2013 https://apod.nasa.gov/apod/ap131120.html, where it was labelled that the artist's impression is for the system 4U1630-47, which was investigated by CSIRO and ESA.] [In] that discussion the same question about the bright white spot was asked and BDanielMayField gave an answer just like Ann's.

BDanielMayfield wrote:
That bright spot would be the place where gas falling from the companion star hits the rapidly rotating outer edge of the accretion disk. Friction from this collision is what would cause this point to be white hot. The rotation rate gets faster and faster of course as the gas/plasma in the accretion disk spirals toward the black hole. Friction between particles heats this material again as it migrates toward the inner edge of the disk.

https://en.wikipedia.org/wiki/Pinch_(plasma_physics) wrote:
<<A pinch is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal. Pinches were the first device used by humankind for controlled nuclear fusion. The phenomenon may also be referred to as a Bennett pinch (after Willard Harrison Bennett), electromagnetic pinch, magnetic pinch, pinch effect or plasma pinch. Pinches occur naturally in electrical discharges such as lightning bolts, the aurora, current sheets, and solar flares.>>

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(1) Pinches apply a huge voltage across a tube. This tube is filled with fusion fuel, typically deuterium gas. If the multiplication of the voltage & the charge is higher than the ionization energy of the gas the gas ionizes. (2) Current jumps across this gap. (3) The current makes a magnetic field which is perpendicular to the current. This magnetic field pulls the material together. (4) These atoms can get close enough to fuse.

neufer wrote:

BDanielMayfield, ages ago wrote: That bright spot would be the place where gas falling from the companion star hits the rapidly rotating outer edge of the accretion disk. Friction from this collision is what would cause this point to be white hot. The rotation rate gets faster and faster of course as the gas/plasma in the accretion disk spirals toward the black hole. Friction between particles heats this material again as it migrates toward the inner edge of the disk.

I don't believe that the gas falling from the companion star actually ever "hits" the rapidly rotating outer edge of the accretion disk.

Rather... the gas stream probably smoothly converges into a tight non-intersecting spiral
(with each spiral band moving at approximately the same velocity as its neighboring bands in any event).

I think someone took a close look at the strong confluence taking place at the entry point of the accretion disk spiral and determined that that would be the ideal spot for Z-pinch fusion of hydrogen to occur:

https://en.wikipedia.org/wiki/Pinch_(plasma_physics) wrote:
<<A pinch is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal. Pinches were the first device used by humankind for controlled nuclear fusion. The phenomenon may also be referred to as a Bennett pinch (after Willard Harrison Bennett), electromagnetic pinch, magnetic pinch, pinch effect or plasma pinch. Pinches occur naturally in electrical discharges such as lightning bolts, the aurora, current sheets, and solar flares.>>

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(1) Pinches apply a huge voltage across a tube. This tube is filled with fusion fuel, typically deuterium gas. If the multiplication of the voltage & the charge is higher than the ionization energy of the gas the gas ionizes. (2) Current jumps across this gap. (3) The current makes a magnetic field which is perpendicular to the current. This magnetic field pulls the material together. (4) These atoms can get close enough to fuse.

BDanielMayfield wrote:
However, remembering a few times when I've been snookered by the Artful neufer, I must ask: Has this Z-pinch at the outer edge of the accretion disk been confirmed or observed? Perhaps I shouldn't relinquish my earlier notion quite so easily.

Why would gas spilling from the swelling star not fall more directly towards the BH? What would cause a Z-pinch compression at that particular site?

• However, I have no idea if it actually is
  or even if the 'artwork' is realistic in regards to the hot spot.

neufer wrote:All I can say is that I think the 'artwork' itself was probably based on the Z-PINCH fusion idea (rather than any collision).

• However, I have no idea if it actually is
  or even if the 'artwork' is realistic in regards to the hot spot.

neufer wrote: I don't believe that the gas falling from the companion star actually ever "hits" the rapidly rotating outer edge of the accretion disk.

Rather... the gas stream probably smoothly converges into a tight non-intersecting spiral
(with each spiral band moving at approximately the same velocity as its neighboring bands in any event).

I think someone took a close look at the strong confluence taking place at the entry point of the accretion disk spiral and determined that that would be the ideal spot for Z-pinch fusion of hydrogen to occur:

https://en.wikipedia.org/wiki/Pinch_(plasma_physics) wrote:
<<A pinch is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal. Pinches were the first device used by humankind for controlled nuclear fusion. The phenomenon may also be referred to as a Bennett pinch (after Willard Harrison Bennett), electromagnetic pinch, magnetic pinch, pinch effect or plasma pinch. Pinches occur naturally in electrical discharges such as lightning bolts, the aurora, current sheets, and solar flares.>>

Ann wrote:

neufer wrote: I don't believe that the gas falling from the companion star actually ever "hits" the rapidly rotating outer edge of the accretion disk.

Rather... the gas stream probably smoothly converges into a tight non-intersecting spiral
(with each spiral band moving at approximately the same velocity as its neighboring bands in any event).

I think someone took a close look at the strong confluence taking place at the entry point of the accretion disk spiral and determined that that would be the ideal spot for Z-pinch fusion of hydrogen to occur:

https://en.wikipedia.org/wiki/Pinch_(plasma_physics) wrote:
<<A pinch is the compression of an electrically conducting filament by magnetic forces. The conductor is usually a plasma, but could also be a solid or liquid metal. Pinches were the first device used by humankind for controlled nuclear fusion. The phenomenon may also be referred to as a Bennett pinch (after Willard Harrison Bennett), electromagnetic pinch, magnetic pinch, pinch effect or plasma pinch. Pinches occur naturally in electrical discharges such as lightning bolts, the aurora, current sheets, and solar flares.>>

Fascinating, Art. I hadn't really thought of what causes the bright light of lightning bolts. So it is indeed fusion?

Some years ago a 14-year-old Swedish girl was knocked unconscious by a bolt of lightning. Otherwise unhurt, she told reporters afterwards:

"All I remember is a flash of bright blue light."

So, Art, and others who might know, are lightning bolts typically hot enough to be blue? What temperature are they usually?

Ann

geckzilla wrote:If the plasma created by lightning emits black-body radiation, then, at well over 10000 K, it should be blue.