APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

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Expand view Topic review: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Thu Jan 14, 2021 7:27 am

If the foreground galaxy, NGC 3314B, has outer dusty thorus we would not see it.
The hole or brane or disk central part occupies the whole backlight area.
Or may be there is no outer dusty thorus.

And yes, the brown/blue galaxy against backlight/black is amazing here

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Ann » Tue Jan 12, 2021 6:31 am

VictorBorun wrote: Mon Jan 11, 2021 10:22 pm What I find surprising about that secretive dusty outskirts beside the fact that it's huge and dwarfing the light-emitting part of the galaxy.
It's clearly non-planar. So the normal matter (can not call it light matter any more) part is overall not a disk but an R=200 kly thorus with an R=20 kly disk brane across the hole. The brane gets thinner at R=4 kly where its prone to form a stable bar ripple, and at R=1 kly there is a core super globular stellar cluster, and at R=1 ly there may be a tiny thorus and disk of accretion by the central black hole.

But how the dusty outskirts survive at such distance from the dark matter globe halo — which is of constant density at R<4 kly and rarefy to nothing at R=40 kly? The dusty skirt is so lose it should have been stripped at encounters with other galaxies.

Maybe they do things different at faraway galaxy clusters. In some each galaxy has a compact dark halo, in others each galaxy has a dusty outskirt.
Victor, much of that is math-speak that you will have to ask someone else about. But I do want to show you another pair of overlapping galaxies.

NGC 3314 is a pair of overlapping but non-interacting galaxies, which is to say that they are so far separated that they don't affect one another gravitationally.

As you can see, the dust lanes of the foreground galaxy, NGC 3314B, look very dark when seen in silhouette against the bright disk of galaxy NGC 3314A. But when seen against the blackness of space, the dust of NGC 3314B almost "disappears". By contrast, the blue star clusters of the arms of NGC 3314B become very obvious against the black background of space, but when seen against the bright background of the disk of NGC 3314A, they almost disappear.

We have good reasons to think that there is more star formation in the extended arms of NGC 3314B than there is closer to the center of that galaxy. It seems likely, too, that there is more dark and concentrated dust closer to the center of NGC 3314B than in the outer parts of the arms.

Still, I think it is remarkable to see how NGC 3314B turns from "brown" when seen in silhouette against the bright disk of NGC 3314A, to "blue" when seen against the blackness of space.

Ann

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Mon Jan 11, 2021 10:22 pm

What I find surprising about that secretive dusty outskirts beside the fact that it's huge and dwarfing the light-emitting part of the galaxy.
It's clearly non-planar. So the normal matter (can not call it light matter any more) part is overall not a disk but an R=200 kly thorus with an R=20 kly disk brane across the hole. The brane gets thinner at R=4 kly where its prone to form a stable bar ripple, and at R=1 kly there is a core super globular stellar cluster, and at R=1 ly there may be a tiny thorus and disk of accretion by the central black hole.

But how the dusty outskirts survive at such distance from the dark matter globe halo — which is of constant density at R<4 kly and rarefy to nothing at R=40 kly? The dusty skirt is so lose it should have been stripped at encounters with other galaxies.

Maybe they do things different at faraway galaxy clusters. In some each galaxy has a compact dark halo, in others each galaxy has a dusty outskirt.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by neufer » Mon Jan 11, 2021 6:46 pm

Ann wrote: Mon Jan 11, 2021 6:13 pm
VictorBorun wrote: Mon Jan 11, 2021 4:09 pm
" a small foreground galaxy " has a bar, doesn't it?
Victor, I wish I knew, but I don't!

I joined Galaxy Zoo for a while, where you were supposed to classify galaxies, but
I gave up quickly because they asked me if the little blobs they showed me had a bar.

How the heck would I know?
https://www.classicfm.com/discover-music/latest/minor-key-joke/ wrote:
<<C, E-flat, and G go into a bar. The bartender says, "Sorry, but we don't serve minors." So E-flat leaves, and C and G have an open fifth between them. After a few drinks, the fifth is diminished, and G is out flat. F comes in and tries to augment the situation, but is not sharp enough. D comes in and heads for the bathroom, saying, "Excuse me; I'll just be a second." Then A comes in, but the bartender is not convinced that this relative of C is not a minor. Then the bartender notices B-flat hiding at the end of the bar and says, "Get out! You're the seventh minor I've found in this bar tonight."

E-flat comes back the next night in a three-piece suit with nicely shined shoes. The bartender says, "You're looking sharp tonight. Come on in, this could be a major development." Sure enough, E-flat soon takes off his suit and everything else, and is au natural. Eventually C sobers up and realizes in horror that he's under a rest. C is brought to trial, found guilty of contributing to the diminution of a minor, and is sentenced to 10 years of D.S. without Coda at an upscale correctional facility.
>>

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Ann » Mon Jan 11, 2021 6:13 pm

VictorBorun wrote: Mon Jan 11, 2021 4:09 pm " a small foreground galaxy " has a bar, doesn't it?
NGC 6822 Waddington.png
Barred irregular galaxy NGC 6822. Photo: Bruce Waddington.
Victor, I wish I knew, but I don't! I joined Galaxy Zoo for a while, where you were supposed to classify galaxies, but I gave up quickly because they asked me if the little blobs they showed me had a bar. How the heck would I know?

As for that little foreground thing seen in front of the large galaxy with the impossibly long name, it looks like an irregular galaxy to me. Not that that means it can't be barred!
By the way, ink-black gobule is easy to tell from deep space black when you have an infrared picture to compare.
Ink-black is quite see-through in infrared.
Right you are, Victor. Dusty areas usually look transparent in infrared photography, whereas the emptiness of space looks black.

Ann

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Mon Jan 11, 2021 4:09 pm

" a small foreground galaxy " has a bar, doesn't it?

By the way, ink-black gobule is easy to tell from deep space black when you have an infrared picture to compare.
Ink-black is quite see-through in infrared.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Ann » Mon Jan 11, 2021 7:53 am

VictorBorun wrote: Mon Jan 11, 2021 5:31 am
orin stepanek wrote: Mon Jan 11, 2021 1:35 am OMG! Has anyone seen the man smiling to the right looking at the
stars?
He has just drawn a puzzle for us: what black is background black and what black is foreground black.
on the left the black is cosmologic background and on the right the black is foreground Bok globules.
Got a better one for you. :wink:

Dark is dark, and sometimes the dark stuff is foreground dust and sometimes it's just space.

Which begs the question as to why space is dark. Well, the best of the short answers, I guess, is that space is young and it has expanded fast, so that its expansion has outrun the speed of light, so that the light from many distant stars has not yet reached us and perhaps never will.

And maybe there is so much space out there that there simply aren't enough stars to cram space full of starlight anyway.

Ann

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Mon Jan 11, 2021 5:31 am

orin stepanek wrote: Mon Jan 11, 2021 1:35 am OMG! Has anyone seen the man smiling to the right looking at the
stars?
He has just drawn a puzzle for us: what black is background black and what black is foreground black.
on the left the black is cosmologic background and on the right the black is foreground Bok globules.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by orin stepanek » Mon Jan 11, 2021 1:35 am

30dor_hubble_960.jpg

OMG! Has anyone seen the man smiling to the right looking at the
stars?

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Mon Jan 11, 2021 1:34 am

ImageImage
Nice sight: if a garland of super giant stars is partially eclipsed by a super dense Bok globule, the light may just barely come through.

In near infrared 110W+160W that Bok globule is not nearly so dense and the stars shine right through.
It proves that in visible light they were trying to get through the ink-black globule and just showed it.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Mon Jan 11, 2021 12:35 am

And are they background tiles? They may be foreground cast-iron fence, two adjoining squares of different size:

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by johnnydeep » Sun Jan 10, 2021 10:27 pm

Chris Peterson wrote: Sun Jan 10, 2021 6:18 pm
johnnydeep wrote: Sun Jan 10, 2021 6:13 pm
Chris Peterson wrote: Sun Jan 10, 2021 4:20 pm

He's talking about the two red structures in the cavity, which look like a square and a triangle (or a square and square that is partly blocked from view along its diagonal). So yes, they do look a bit like tiles. But that's just pareidolia and our brain looking for patterns. It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning. Like the lines of stars that often jump out as us in rich star fields.
Ah. So these “tiles” then, I suppose:

57F6A849-8904-4C32-A25A-5CADB156A504.jpeg

Not very tile-like to me. Then again, I never see much of anything in Rorschach ink blot tests either. :ssmile:
But you were able to see them well enough once they were pointed out, given the precision of your outlines.
Yes, but it was a struggle, and I still wasn’t positive I found the same shapes as you guys.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by MarkBour » Sun Jan 10, 2021 7:18 pm

I've seen a couple of images of R136 before, but never realized that it was outside of the Milky Way.
To have this much resolution in an image of a star cluster that's 170,000 light years away seems quite amazing to me.
Ann wrote: Sun Jan 10, 2021 5:50 am ...
Note in the image of NGC 604 how the fierce stellar winds have blown bubbles in the surrounding nebula. Note the "wall" separating two large cavities, one on the left and one on the right.

The cavity on the right is full of massive stars, whereas the cavity on the left seems almost empty by comparison. The cavity on the left is clearly older, and the most massive stars that were born there there have spent their youthful energy and exploded as supernovas or turned into white dwarfs. But the stars in the cavity on the right are still in the prime of their lives.

Ann
I see what you're saying. The stars of the left cavity may have in some sense been the parents of the stars in the right cavity. (And, like good parents, they have faded, but can behold the glory of their children.)

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Chris Peterson » Sun Jan 10, 2021 6:18 pm

johnnydeep wrote: Sun Jan 10, 2021 6:13 pm
Chris Peterson wrote: Sun Jan 10, 2021 4:20 pm
johnnydeep wrote: Sun Jan 10, 2021 4:14 pm

"Ghostly red tiles"? I don't see them. Can you point them out with a pic and arrows?
He's talking about the two red structures in the cavity, which look like a square and a triangle (or a square and square that is partly blocked from view along its diagonal). So yes, they do look a bit like tiles. But that's just pareidolia and our brain looking for patterns. It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning. Like the lines of stars that often jump out as us in rich star fields.
Ah. So these “tiles” then, I suppose:

57F6A849-8904-4C32-A25A-5CADB156A504.jpeg

Not very tile-like me. Then again, I never see much of anything in Rorschach ink blot tests either. :ssmile:
But you were able to see them well enough once they were pointed out, given the precision of your outlines.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by johnnydeep » Sun Jan 10, 2021 6:13 pm

Chris Peterson wrote: Sun Jan 10, 2021 4:20 pm
johnnydeep wrote: Sun Jan 10, 2021 4:14 pm
VictorBorun wrote: Sun Jan 10, 2021 2:58 pm unusual to see spiked stars in another galaxy. They are bright and the LMC galaxy is near.

I wonder what large ghostly red tiles in the background of the top half of the left cavity can be.
They don't feel astronomic at all.
"Ghostly red tiles"? I don't see them. Can you point them out with a pic and arrows?
He's talking about the two red structures in the cavity, which look like a square and a triangle (or a square and square that is partly blocked from view along its diagonal). So yes, they do look a bit like tiles. But that's just pareidolia and our brain looking for patterns. It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning. Like the lines of stars that often jump out as us in rich star fields.
Ah. So these “tiles” then, I suppose:
Ghostly Red Tiles? Hardly!
Ghostly Red Tiles? Hardly!
Not very tile-like to me. Then again, I never see much of anything in Rorschach ink blot tests either. :ssmile:

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Chris Peterson » Sun Jan 10, 2021 5:23 pm

VictorBorun wrote: Sun Jan 10, 2021 5:21 pm
Chris Peterson wrote: Sun Jan 10, 2021 4:20 pm
johnnydeep wrote: Sun Jan 10, 2021 4:14 pm "Ghostly red tiles"?
It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning.
linear shock front…
Like this?
If we view it that close, we tend to see other structure. But that one, viewed at lower resolution, would look pretty similar to a straight line.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Sun Jan 10, 2021 5:21 pm

Chris Peterson wrote: Sun Jan 10, 2021 4:20 pm
johnnydeep wrote: Sun Jan 10, 2021 4:14 pm "Ghostly red tiles"?
It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning.
linear shock front…
Like this?

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by johnnydeep » Sun Jan 10, 2021 4:26 pm

Ann wrote: Sun Jan 10, 2021 5:50 am
Professor Paul Crowther, University of Sheffield, wrote about the data that had been collected about R136a by STIS:

The ultraviolet STIS spectral survey of all stars more massive than ~25 solar masses has revealed:

a) the bulk of the visual brightest members of R136 are O2-3 stars
b) comparison of wind velocities of early O stars with those elsewhere in the LMC and the Milky Way indicate somewhat lower velocities for R136 stars
c) physical parameter estimates reveal several dozen stars more massive than 50 solar masses, with 9 stars exceeding 100 solar masses (including R136c)
d) we obtain a cluster mass of approximately 1.5 Myr
e) we have considered the integrated UV spectrum of R136a - close to 100 per cent of the HeII 1640 flux and 32 per cent of the far-UV continuum arises from very massive stars. Prominent HeII emission in the integrated spectrum of young star clusters would favour a mass function that extends well above 100 solar masses
Minor correction to the Crowther article: a "mass" of 1.5 Myr? So, it's probably either an age of 1.5 Myr, or a mass of 1.5 M☉. Per the wikipedia article about R136, it's the age.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Chris Peterson » Sun Jan 10, 2021 4:20 pm

johnnydeep wrote: Sun Jan 10, 2021 4:14 pm
VictorBorun wrote: Sun Jan 10, 2021 2:58 pm unusual to see spiked stars in another galaxy. They are bright and the LMC galaxy is near.

I wonder what large ghostly red tiles in the background of the top half of the left cavity can be.
They don't feel astronomic at all.
"Ghostly red tiles"? I don't see them. Can you point them out with a pic and arrows?
He's talking about the two red structures in the cavity, which look like a square and a triangle (or a square and square that is partly blocked from view along its diagonal). So yes, they do look a bit like tiles. But that's just pareidolia and our brain looking for patterns. It's a region of ionized hydrogen and it has some linear shock fronts around it (which are common enough). That they coincidentally lie at about 90° to each other makes our brains see structure that has no real physical meaning. Like the lines of stars that often jump out as us in rich star fields.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by johnnydeep » Sun Jan 10, 2021 4:14 pm

VictorBorun wrote: Sun Jan 10, 2021 2:58 pm unusual to see spiked stars in another galaxy. They are bright and the LMC galaxy is near.

I wonder what large ghostly red tiles in the background of the top half of the left cavity can be.
They don't feel astronomic at all.
"Ghostly red tiles"? I don't see them. Can you point them out with a pic and arrows?

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Chris Peterson » Sun Jan 10, 2021 4:11 pm

Robolt wrote: Sun Jan 10, 2021 3:42 pm Why do nearby stars, but not distant ones, show the spikes in the image?
Every star has diffraction spikes. Whether they rise above the noise floor and are visible is determined only by intensity. A star that is four times brighter and twice as far away will show identical spikes to one that is a quarter as bright and twice as close.

It looks like most or all of the bright stars in this image are at about the same distance, so the degree they show spikes is largely determined by their luminosity. There is no way from the image alone of accurately assessing which stars are closer and which are farther away.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by neufer » Sun Jan 10, 2021 3:58 pm

Robolt wrote: Sun Jan 10, 2021 3:42 pm
Why do nearby stars, but not distant ones, show the spikes in the image?
Why do you think that all the stars with (diffraction) spikes are "nearby" stars?

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by Robolt » Sun Jan 10, 2021 3:42 pm

Why do nearby stars, but not distant ones, show the spikes in the image?

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by VictorBorun » Sun Jan 10, 2021 2:58 pm

unusual to see spiked stars in another galaxy. They are bright and the LMC galaxy is near.

I wonder what large ghostly red tiles in the background of the top half of the left cavity can be.
They don't feel astronomic at all.

Re: APOD: Star Cluster R136 Breaks Out (2021 Jan 10)

by orin stepanek » Sun Jan 10, 2021 1:36 pm

30dor_hubble_960.jpg

I'm noticing what looks like a lot of double stars! 8-)
Very beautiful picture from 30 Doradus; Cluster R136!

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