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

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4779
Joined: Fri Dec 04, 2009 3:27 am

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

Post by APOD Robot » Sat May 28, 2022 4:06 am

Image RCW 86: Historical Supernova Remnant

Explanation: In 185 AD, Chinese astronomers recorded the appearance of a new star in the Nanmen asterism. That part of the sky is identified with Alpha and Beta Centauri on modern star charts. The new star was visible for months and is thought to be the earliest recorded supernova. This deep image shows emission nebula RCW 86, understood to be the remnant of that stellar explosion. The narrowband data trace gas ionized by the still expanding shock wave. Space-based images indicate an abundance of the element iron and lack of a neutron star or pulsar in the remnant, suggesting that the original supernova was Type Ia. Unlike the core collapse supernova explosion of a massive star, a Type Ia supernova is a thermonuclear detonation on a a white dwarf star that accretes material from a companion in a binary star system. Near the plane of our Milky Way galaxy and larger than a full moon on the sky this supernova remnant is too faint to be seen by eye though. RCW 86 is some 8,000 light-years distant and around 100 light-years across.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post by Ann » Sat May 28, 2022 6:47 am

Supernova remnants are interesting as astro-archeological finds in the sky. Finding supernova remnants in the sky is a bit like finding shards of broken pottery from previous civilizations in the ground.

I like this portrait of the Galactic center from the MeerKAT radio array in South Africa ( and I hope I get to keep the picture):


Interesting, isn't it? "SNR" means supernova remnant. So as you can see, there are several supernova remnants in the Galactic core.

As for today's APOD, I'm slightly surprised that the remnant is so tattered and so apparently close to "disintegration", in view of the fact that the supernova remnant is not that old, less than 2,000 years. Don't they last longer than that? But perhaps this supernova remnant is located in a "busy" part of the Milky Way, where there are many large molecular clouds and heavy stellar traffic to tear the hapless supernova remnant asunder? But its environment in today's APOD looks kind of uneventful.

The supernova remnant is remarkably asymmetrical:

Supernova remnant RCW 86 Martin Pugh.png

Anyway. RCW 86 is the remnant of a type Ia supernova. The progenitors of these supernovas are made of "prime fuel" through and through, because their cores are made of lighter-than-iron elements that can be used to extract energy through fusion. 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.)

Anyway, today's APOD gives me a chance to post a picture that I have wanted to post for a long time:

Puppis A supernova remnant Spitzer Chandra dead astronaut.png

Does this supernova remnant, Puppis A, look like a dead astronaut floating in space? You bet it does! And it is fitting that it should look like a dead astronaut, too, because a supernova remnant is like a "dead star floating in space".

Puppis A is interesting in itself:
Spitzer Caltech wrote:

The destructive results of a mighty supernova explosion reveal themselves in a delicate blend of infrared and X-ray light, as seen in this image from NASAs Spitzer Space Telescope and Chandra X-Ray Observatory, and the European Space Agency's XMM-Newton.

The bubbly cloud is an irregular shock wave, generated by a supernova that would have been witnessed on Earth 3,700 years ago. The remnant itself, called Puppis A, is around 7,000 light-years away, and the shock wave is about 10 light-years across.
Yeah? Puppis A supernova would have been witness by humans 3,700 years ago, but its remnant is still, well, "going strong". But the RCW 86 supernova remnant in today's APOD looks definitely worse for wear, even though it is only half as old as Puppis A. What gives?

Maybe the answer is that RCW 86 was photographed in visible light, but Puppis A was imaged in infrared light and X-rays?

Ann
You do not have the required permissions to view the files attached to this post.
Color Commentator

User avatar
AVAO
Science Officer
Posts: 170
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

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

Post 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

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

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

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post 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

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

Image
Credit: NASA/JPL-Caltech/B. Williams (NCSU)
https://chandra.harvard.edu/photo/2011/rcw86/more.html
Thanks, AVAO, very interesting!

Ann
Last edited by Ann on Sat May 28, 2022 1:10 pm, edited 2 times in total.
Color Commentator

User avatar
orin stepanek
Plutopian
Posts: 7722
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

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

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

Hmmm!

.jpg
RCW86_MP1024.jpg
Kinda reminds me of kitty falling! :mrgreen:
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

De58te
Science Officer
Posts: 496
Joined: Mon Sep 30, 2013 6:35 pm

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

Post 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.

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

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

Post 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

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post by Ann » Sat May 28, 2022 5:39 pm

orin stepanek wrote: Sat May 28, 2022 12:24 pm Hmmm!
Kinda reminds me of kitty falling! :mrgreen:
Love the kittie, Orin! :D :kitty: I agree that there is a similarity between the shape of the kitty and the shape of the supernova remnant! 😃

Ann
Color Commentator

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post 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:

Supernova remnant RCW 86 fast moving progenitor Spitzer WISE.png
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:


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
You do not have the required permissions to view the files attached to this post.
Color Commentator

DL MARTIN

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

Post 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?

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

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

Post 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?

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
orin stepanek
Plutopian
Posts: 7722
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

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

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

Ann wrote: Sat May 28, 2022 5:39 pm
Love the kittie, Orin! :D :kitty: 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!
Orin

Smile today; tomorrow's another day!

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

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

Post 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:
no Southern Gate.jpg
You do not have the required permissions to view the files attached to this post.

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post 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:

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
Last edited by Ann on Mon May 30, 2022 2:06 pm, edited 1 time in total.
Color Commentator

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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:

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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Ann
4725 Å
Posts: 12253
Joined: Sat May 29, 2010 5:33 am

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

Post 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

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
Color Commentator

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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!
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

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

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

Chris Peterson wrote: Mon May 30, 2022 2:03 pm
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
You do not have the required permissions to view the files attached to this post.

User avatar
Chris Peterson
Abominable Snowman
Posts: 16916
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

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

Post 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
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.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
VictorBorun
Commander
Posts: 624
Joined: Fri Oct 16, 2020 10:25 pm

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

Post 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
Image
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?
You do not have the required permissions to view the files attached to this post.

User avatar
AVAO
Science Officer
Posts: 170
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

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

Post 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
Image
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