APOD: Spiral Galaxy NGC 6744 (2022 Jun 23)

[Ann]

I'd say there is a bar.

Ann

[Chris Peterson]

Bar of NGC 6744 APOD 23 June 2022.png

I'd say there is a bar.

Ann

Maybe. But I'm far from convinced. In particular, the odd coincidence of it lining up with the tip axis... which is exactly the direction we would expect to see both artifacts and optical illusions in... is suspicious.

[AVAO]

...As the galaxy is a disc, that would imply that the core is, as well.

...maybe ...maybe not...but definitely a foggy area there


https://www.flickr.com/photos/185130090 ... ed-public/
jac berne (flickr)

[Locutus76]

In the June 23, 2022 APOD of the Spiral Galaxy NGC 6744, there is a blue dot along the ~11:00 line moving away from the galaxy. Quite a few of the stars have a light blue color, but this star(?) has a distinctly different color (a darker blue) from all the others. What is it? and what gives it this deeper blue color?

A similar darker blue star can be found at the exact opposide side of NCC 6744, around the 4:00 line near the edge of the image…

There are several little blue dots scattered in the disk. They are almost certainly clusters.

In fact, they are clusters. Because NGC 6744 is a very big galaxy with quite small clusters.

Ann

Indeed. However the blue dot I was referring to lies well outside NGC 6744, almost near the bottom of the image. I can’t post an image apparently, but if you follow NGC 6744A almost straight down to the small group of 4 stars near the image edge, then the blue one is just above and right of that small group. Not very important, I know. But remarkably blue it is.

[johnnydeep]

A similar darker blue star can be found at the exact opposide side of NCC 6744, around the 4:00 line near the edge of the image…

There are several little blue dots scattered in the disk. They are almost certainly clusters.

In fact, they are clusters. Because NGC 6744 is a very big galaxy with quite small clusters.

Ann

Indeed. However the blue dot I was referring to lies well outside NGC 6744, almost near the bottom of the image. I can’t post an image apparently, but if you follow NGC 6744A almost straight down to the small group of 4 stars near the image edge, then the blue one is just above and right of that small group. Not very important, I know. But remarkably blue it is.

I'm not finding that. But the bluest round thing I see is this one in the top left quadrant:

I can't believe that's "just" a cluster so far away from NGC 6744... or is it?

[Ann]

There are several little blue dots scattered in the disk. They are almost certainly clusters.

In fact, they are clusters. Because NGC 6744 is a very big galaxy with quite small clusters.

Ann

Indeed. However the blue dot I was referring to lies well outside NGC 6744, almost near the bottom of the image. I can’t post an image apparently, but if you follow NGC 6744A almost straight down to the small group of 4 stars near the image edge, then the blue one is just above and right of that small group. Not very important, I know. But remarkably blue it is.

I'm not finding that. But the bluest round thing I see is this one in the top left quadrant:

Click to view full size image

I can't believe that's "just" a cluster so far away from NGC 6744... or is it?

That doesn't look like a star cluster at all. It looks very much like a single star.

There are at least three blue stars near the bottom of the image:

These objects look like stars to me. It is interesting that they are so faint.

It is hard to say why stars would be so small and faint and also so blue. It is tempting to say that they are white dwarfs, but white dwarfs are typically so faint that they wouldn't show up in an image like this.

White dwarf stars in globular cluster NGC 6397.

---

Another possibility is that these stars are bluish, and that they look very blue precisely because they are so faint, so that they are not at all overexposed. Brighter blue stars might look much whiter, because they would be more overexposed.

In the end though, your guess as to what these objects are is as good as mine.

Ann