Starship Asterisk*

by **VictorBorun** » Tue May 31, 2022 8:15 pm

AVAO wrote: ↑Tue May 31, 2022 5:16 pm I had the exact same idea while doing my research. But I could not identify a post-SN stellar system moving fast in the opposite directions.
thanX Jac

With time they will move angularily for an Earth observer and get identified

by **VictorBorun** » Tue May 31, 2022 7:27 pm

I have just read about a hypothetical mechanism that may work here:

if a Super Nova happens in a tight binary and sheds half of its mass, then even a spherical symmetric SN blow-up would leave the pair (a neutron star and a star) moving fast in opposite directions after their gravitational string got 2 times weaker and tore apart

Now the star, of 1 sun mass and enriched in Ca and other nucleosynthesis products of the SN, is just inside the shock bow at bottom right of the posted optical pic and of the X-rays Chandra's pic and of radio pic.
So the neutron star must be somewhere inside the other shock bow at top left of the X-rays Chandra's pic and of radio pic.
here is radio = red, X-rays = green and blue

by **AVAO** » Tue May 31, 2022 5:16 pm

VictorBorun wrote: ↑Mon May 30, 2022 3:31 pm
AVAO wrote: ↑Sat May 28, 2022 7:12 am "We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse. We find that the solar-type star is strongly polluted with calcium and other elements, which places the explosion within the class of calcium-rich supernovae – faint and fast transients, whose origin is strongly debated, and provides the first observational evidence that supernovae of this type can arise from core-collapse explosions." https://arxiv.org/abs/1702.00936

https://live.staticflickr.com/65535/521 ... 31ab_k.jpg
Composit image by Jac Berne (flickr)

I tried to use Composit image by Jac Berne as an in-between to fit the composite IR + X-rays:
RCW86_MP IR + X-ray after fitting to Jac Berne's composit.jpg
and the posted pic:
RCW86_MP after fitting to Jac Berne's composit.jpg

It looks like there are two shock bows, the main at the bottom right and another at the top left, invisible in the posted pic.
Were there two post-SN stellar systems, moving fast in the opposite directions?

I had the exact same idea while doing my research. But I could not identify a post-SN stellar system moving fast in the opposite directions.

thanX Jac

by **VictorBorun** » Mon May 30, 2022 3:31 pm

AVAO wrote: ↑Sat May 28, 2022 7:12 am "We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse. We find that the solar-type star is strongly polluted with calcium and other elements, which places the explosion within the class of calcium-rich supernovae – faint and fast transients, whose origin is strongly debated, and provides the first observational evidence that supernovae of this type can arise from core-collapse explosions." https://arxiv.org/abs/1702.00936

https://live.staticflickr.com/65535/521 ... 31ab_k.jpg
Composit image by Jac Berne (flickr)

I tried to use Composit image by Jac Berne as an in-between to fit the composite IR + X-rays:

and the posted pic:

It looks like there are two shock bows, the main at the bottom right and another at the top left, invisible in the posted pic.
Were there two post-SN stellar systems, moving fast in the opposite directions?

by **Chris Peterson** » Mon May 30, 2022 3:24 pm

VictorBorun wrote: ↑Mon May 30, 2022 3:14 pm
Chris Peterson wrote: ↑Mon May 30, 2022 2:03 pm
VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.
But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:
Click to view full size image

But the story doesn't say it was located near ε Centaurus. It was simply located in a large asterism which contains that star.
here's The Horn mansion with Southern Gate [南門] at the bottom.
I take it α Centauri is at the left bottom of the passage way, β Centauri stands in the way and ε Centauri is at the right end of the roof.
It puts the Guest star of the half a bamboo mat's size below Southern Gate rather than in the middle
The Horn mansion.jpg

I'd say, from the description, it doesn't place it anywhere obvious. I don't know that we even fully know how the asterism was interpreted.

by **VictorBorun** » Mon May 30, 2022 3:14 pm

Chris Peterson wrote: ↑Mon May 30, 2022 2:03 pm
VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.
But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:
Click to view full size image

But the story doesn't say it was located near ε Centaurus. It was simply located in a large asterism which contains that star.

here's The Horn mansion with Southern Gate [南門] at the bottom.
I take it α Centauri is at the left bottom of the passage way, β Centauri stands in the way and ε Centauri is at the right end of the roof.
It puts the Guest star of the half a bamboo mat's size below Southern Gate rather than in the middle

by **Chris Peterson** » Mon May 30, 2022 2:24 pm

Ann wrote: ↑Mon May 30, 2022 2:01 pm Please note that, because Alpha Centauri is so nearby, it is likely to move rather fast across the sky (relative to the Sun), and it may not have been a part of the Southern Gate asterism at the time when the supernova exploded there in 150 A.D.

It has moved about 2° since then, so the shape of the asterism hasn't changed all that much (and that star was likely one of the defining features of the asterism, in any case). It is interesting to consider precession, however. In 185 CE Centaurus was 10° higher in the southern sky. Today, much of that constellation cannot be seen from large parts of China.

by **Chris Peterson** » Mon May 30, 2022 2:09 pm

Ann wrote: ↑Mon May 30, 2022 2:07 pm
Chris Peterson wrote: ↑Mon May 30, 2022 2:03 pm
Ann wrote: ↑Mon May 30, 2022 2:01 pm

I agree with you. I googled "RCW 86 coordinates" and got the following ones: RA 14h 45m 02.30s | Dec -62º 20' 32.00"

That's nowhere near Epsilon Centauri. Instead, it is located between Alpha Centauri and Alpha Circini, just like your picture shows us.

Ann
But the story doesn't say it was located near ε Centaurus. It was simply located in a large asterism which contains that star.
Yes, Chris, but I just edited my post.

You gotta be quick around here sometimes!

by **Ann** » Mon May 30, 2022 2:07 pm

Chris Peterson wrote: ↑Mon May 30, 2022 2:03 pm
Ann wrote: ↑Mon May 30, 2022 2:01 pm
VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm

I can't make any sense of the Chinese story.
Wiki says:
a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.

But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:

Click to view full size image

I agree with you. I googled "RCW 86 coordinates" and got the following ones: RA 14h 45m 02.30s | Dec -62º 20' 32.00"

That's nowhere near Epsilon Centauri. Instead, it is located between Alpha Centauri and Alpha Circini, just like your picture shows us.

Ann
But the story doesn't say it was located near ε Centaurus. It was simply located in a large asterism which contains that star.

Yes, Chris, but I just edited my post.

Ann

by **Chris Peterson** » Mon May 30, 2022 2:03 pm

Ann wrote: ↑Mon May 30, 2022 2:01 pm
VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm
Ann wrote: ↑Sat May 28, 2022 6:24 pm
As to where exactly RCW 86 is located, you can find its coordinates here.
I can't make any sense of the Chinese story.
Wiki says:
a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.

But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:

Click to view full size image

I agree with you. I googled "RCW 86 coordinates" and got the following ones: RA 14h 45m 02.30s | Dec -62º 20' 32.00"

That's nowhere near Epsilon Centauri. Instead, it is located between Alpha Centauri and Alpha Circini, just like your picture shows us.

Ann

But the story doesn't say it was located near ε Centaurus. It was simply located in a large asterism which contains that star.

by **Ann** » Mon May 30, 2022 2:01 pm

VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm
Ann wrote: ↑Sat May 28, 2022 6:24 pm
VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
2) where is the 3/4 degree bubble of RCW 86 within Centaurus and within Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri]
As to where exactly RCW 86 is located, you can find its coordinates here.
I can't make any sense of the Chinese story.
Wiki says:
a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.

But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:

Click to view full size image

I agree with you. I googled "RCW 86 coordinates" and got the following ones: RA 14h 45m 02.30s | Dec -62º 20' 32.00"

That's nowhere near Epsilon Centauri. Instead, it is located between Alpha Centauri and Alpha Circini, just like your picture shows us.

But okay, Chris, all we know is that the supernova exploded in the part of the sky identified by the ancient Chinese as the Southern Gate.

Please note that, because Alpha Centauri is so nearby, it is likely to move rather fast across the sky (relative to the Sun), and it may not have been a part of the Southern Gate asterism at the time when the supernova exploded there in 150 A.D.

Ann

by **Chris Peterson** » Mon May 30, 2022 2:00 pm

VictorBorun wrote: ↑Mon May 30, 2022 1:33 pm
Ann wrote: ↑Sat May 28, 2022 6:24 pm
VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
2) where is the 3/4 degree bubble of RCW 86 within Centaurus and within Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri]
As to where exactly RCW 86 is located, you can find its coordinates here.
I can't make any sense of the Chinese story.
Wiki says:
a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.

But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:

no Southern Gate.jpg

What is the confusion? Those stars are just part of the asterism where the "guest star" appeared. The story does not say it appeared between those two stars.

by **VictorBorun** » Mon May 30, 2022 1:33 pm

Ann wrote: ↑Sat May 28, 2022 6:24 pm
VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
2) where is the 3/4 degree bubble of RCW 86 within Centaurus and within Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri]
As to where exactly RCW 86 is located, you can find its coordinates here.

I can't make any sense of the Chinese story.
Wiki says:
a 'guest star' appeared in the middle of the Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri], The size was half a bamboo mat. It displayed various colors, both pleasing and otherwise.[4] It gradually lessened. In the 6th month of the succeeding year it disappeared.

But worldwidetelescope.org shows RCW 86 between α Centauri and α Circini instead:

by **orin stepanek** » Sun May 29, 2022 2:35 am

Ann wrote: ↑Sat May 28, 2022 5:39 pm
Love the kittie, Orin! I agree that there is a similarity between the shape of the kitty and the shape of the supernova remnant!

Ann

Cats have a super sense of balance! They seem to always land on their feet!

by **Chris Peterson** » Sat May 28, 2022 10:47 pm

VictorBorun wrote: ↑Sat May 28, 2022 10:22 pm
Ann wrote: ↑Sat May 28, 2022 6:24 pm
VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
4) how can a massive star move fast enough to get to the boundary of its fast wind bubble before it goes SuperNova
As for why the progenitor star moved so fast, it was probably a runaway star. We see lots of them. Read about them here.
I still don't get it.
To kick a star you must kick some other thing with the same linear momentum.

That's one way. You can also have an asymmetrical supernova.

by **VictorBorun** » Sat May 28, 2022 10:22 pm

Ann wrote: ↑Sat May 28, 2022 6:24 pm
VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
4) how can a massive star move fast enough to get to the boundary of its fast wind bubble before it goes SuperNova
As for why the progenitor star moved so fast, it was probably a runaway star. We see lots of them. Read about them here.

I still don't get it.
To kick a star you must kick some other thing with the same linear momentum.

When two BHs merge and the more massive one has a large spin in the plane of the inspiral, a gravitational wave has large both rotation and linear momenta and gives a large recoil, about 1000 km/s, to the merged BH.
But we talk stars here, not a BHs' merger.

When stars in a globular stellar cluster or a galaxy have some peculiar motion, they nearly collide from time to time, exchanging linear momentum. All in all the more massive migrate down to lower orbits and the less massive migrate up or are even kicked out of the stellar cluster or the galaxy.
But we talk here of 10 suns mass star, it should not get kicked easily.

When stars' orbits in a complex system resonate, some stars in that system may get to a closer orbit and others get kicked out.
OK, there could be a complex system with a 100 suns super giant and a pair of 10 suns giant; one of the 10 suns giant got to a close orbit and the other was kicked and started its high speed journey. And it could happen to hold on a tight 1 sun mass star companion, to help later make a 5 suns mass RCW 86 nebula.
But then that 100 suns super giant already went Super Nova and became a BH. Is there a large enough BH in the direction that RCW 86 progenitor came from?

by **Chris Peterson** » Sat May 28, 2022 9:31 pm

DL MARTIN wrote: ↑Sat May 28, 2022 8:09 pm With the use of term astro-archeological finds unchallenged in the discussion segment, are we now prepared to accept that entities in the universe are not just away but ago?

Of course they are "ago". This one happened in historical times, and was recorded, which is unusual. To know this happened 1,837 years ago is very interesting, and provides a rare degree of precision in age.

by **DL MARTIN** » Sat May 28, 2022 8:09 pm

With the use of term astro-archeological finds unchallenged in the discussion segment, are we now prepared to accept that entities in the universe are not just away but ago?

by **Ann** » Sat May 28, 2022 6:24 pm

VictorBorun wrote: ↑Sat May 28, 2022 3:18 pm I wonder
1) why did Ancient Greeks named Centaurus what Babylonians called Man Bull
2) where is the 3/4 degree bubble of RCW 86 within Centaurus and within Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri]
3) why do they say that the bubble of RCW 86 is piriform
4) how can a massive star move fast enough to get to the boundary of its fast wind bubble before it goes SuperNova

Victor, you ask many questions that I can't answer, but I think that the supernova remnant formed like this:

The RCW 86 supernova remnant in infrared.
Data: Spitzer and WISE.

I think the progenitor of RCW 86 was a fast-moving massive star with a solar-mass companion. The pair interacted with another massive star and got a gravitational kick, which sent them "running" at a high speed. During their headlong flight, the massive component exploded as a supernova, and as it did so, it ejected an expanding shell of gas. But the supernova remnant, a neutron star, kept moving in the same direction. The neutron star has now caught up with the expanding supernova shell, and now it is ionizing a small part of that shell, making it glow brightly.

We may compare the appearance of the very bright and rather small arc of RWC 86 with the appearance of the California Nebula and its ionizing runaway star, Xi Per:

: California Nebula being ionized by hot runaway star Xi Per. Image: Remidone.

But wait!! It seems I was wrong about where the progenitor star actually exploded:

V.V. Gvaramadze et.al. wrote:

We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse.

So the supernova progenitor was located at the edge of a bubble of its own creation. All hot stars eventually start blowing a strong wind, which creates a bubble around the star. But if the star moves fast enough, it can almost "outrun" its own wind bubble. The progenitor star was asymmetrically located inside its own wind bubble, near the edge of its own bubble, as it exploded.

So it didn't explode in the middle of the bubble, but near the edge of it.

As for why the progenitor star moved so fast, it was probably a runaway star. We see lots of them. Read about them here.

As to where exactly RCW 86 is located, you can find its coordinates here.

Ann

by **Ann** » Sat May 28, 2022 5:39 pm

orin stepanek wrote: ↑Sat May 28, 2022 12:24 pm Hmmm!

Click to view full size image

Click to view full size image
Kinda reminds me of kitty falling!

Love the kittie, Orin!

I agree that there is a similarity between the shape of the kitty and the shape of the supernova remnant!

Ann

by **VictorBorun** » Sat May 28, 2022 3:18 pm

I wonder
1) why did Ancient Greeks named Centaurus what Babylonians called Man Bull
2) where is the 3/4 degree bubble of RCW 86 within Centaurus and within Southern Gate [南門] [an asterism consisting of ε Centauri and α Centauri]
3) why do they say that the bubble of RCW 86 is piriform
4) how can a massive star move fast enough to get to the boundary of its fast wind bubble before it goes SuperNova

by **De58te** » Sat May 28, 2022 1:03 pm

I wonder if this is a mere coincidence but in the MeerKAT Galactic Center portrait, isn't it strange that the objects in the northern section are objects named after airy, heavenly things such as harp, Christmas Tree and pelican, whereas in the southern section, with the exception of the radio bubble, are objects more ground based, unlikable things (for most people) such as mouse and snake.

by **orin stepanek** » Sat May 28, 2022 12:24 pm

Hmmm!

Kinda reminds me of kitty falling!

by **Ann** » Sat May 28, 2022 9:12 am

AVAO wrote: ↑Sat May 28, 2022 7:12 am
Ann wrote: ↑Sat May 28, 2022 6:47 am ...That's why these supernovas leave no neutron stars behind, because the progenitor stars are like huge solar mass thermonuclear bombs waiting to explode under the right circumstances. (The progenitor stars of core-collapse supernovas, by contrast, have "dead" iron cores that can't be used for fusion, and it is these cores that turn into neutron stars or occasionally black holes in the supernova explosion.)

Ann
...interesting hypothesis...

"We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse. We find that the solar-type star is strongly polluted with calcium and other elements, which places the explosion within the class of calcium-rich supernovae – faint and fast transients, whose origin is strongly debated, and provides the first observational evidence that supernovae of this type can arise from core-collapse explosions." https://arxiv.org/abs/1702.00936

https://live.staticflickr.com/65535/521 ... 31ab_k.jpg
Composit image by Jac Berne (flickr)

Credit: NASA/JPL-Caltech/B. Williams (NCSU)
https://chandra.harvard.edu/photo/2011/rcw86/more.html

Thanks, AVAO, very interesting!

Ann

by **AVAO** » Sat May 28, 2022 7:12 am

Ann wrote: ↑Sat May 28, 2022 6:47 am ...That's why these supernovas leave no neutron stars behind, because the progenitor stars are like huge solar mass thermonuclear bombs waiting to explode under the right circumstances. (The progenitor stars of core-collapse supernovas, by contrast, have "dead" iron cores that can't be used for fusion, and it is these cores that turn into neutron stars or occasionally black holes in the supernova explosion.)

Ann

...interesting hypothesis...

"We report the discovery of a solar-type star in a close, eccentric binary system with a neutron star within the young Galactic supernova remnant RCW 86. Our discovery implies that the supernova progenitor was a moving star, which exploded near the edge of its wind bubble and lost most of its initial mass due to common-envelope evolution shortly before core collapse. We find that the solar-type star is strongly polluted with calcium and other elements, which places the explosion within the class of calcium-rich supernovae – faint and fast transients, whose origin is strongly debated, and provides the first observational evidence that supernovae of this type can arise from core-collapse explosions." https://arxiv.org/abs/1702.00936

https://live.staticflickr.com/65535/521 ... 31ab_k.jpg
Composit image by Jac Berne (flickr)

Credit: NASA/JPL-Caltech/B. Williams (NCSU)
https://chandra.harvard.edu/photo/2011/rcw86/more.html

Starship Asterisk*

APOD: RCW 86: Historical Supernova Remnant (2022 May 28)

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