APOD: Wolf's Cave Nebula (2022 Nov 15)

[APOD Robot]

Wolf's Cave Nebula

Explanation: The mysterious blue reflection nebula found in catalogs as VdB 152 or Ced 201 really is very faint. It lies at the tip of the long dark nebula Barnard 175 in a dusty complex that has also been called Wolf's Cave. At the center of this deep telescopic view, the cosmic apparitions are nearly 1,400 light-years away along the northern Milky Way in the royal constellation Cepheus. Interstellar dust in the region blocks light from background stars and scatters light from the embedded bright star, giving the end nebula its characteristic blue color. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity. At the image bottom is the planetary nebula Dengel-Hartl 5, while red glowing gas from an ancient supernova remnant is also visible along the image's right side.

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[Ann]

Wolf's Cave Nebula. Image Credit & Copyright: Gianni Lacroce

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Beautiful image! The red details really make this image shine. Yes, I do like red sometimes, when it doesn't take over too much from the other colors, and particularly when there is some blue in the image to set it off!


Note the small bluish gray lenticular cloud above the "head" (or the mouth?) of the Wolf Cave Nebula:

Lenticular clouds in the Earth's skies.

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Lentcular clouds above the Wolf's Cave Nebula.

As for the star lighting up the Wolf's Cave Nebula in blue, we are told in the caption that the star just blundered in there:

APOD Robot wrote:

Interstellar dust in the region blocks light from background stars and scatters light from the embedded bright star, giving the end nebula its characteristic blue color. Though stars do form in molecular clouds, this star seems to have only accidentally wandered into the area, as its measured velocity through space is very different from the cloud's velocity.

That's curious. When I googled the star, BD+69 1231, Simbad Astronomical Database called it a young stellar object. I don't expect a young stellar object that has just recently emerged from its birth cocoon to leave its birthplace and just blunder into the best possible other birthplace for young stars some distance away.

The Wolf's Cave Nebula, vdB 152, looks like it might give birth to low-mass stars. Note the dark dust lane just below the bright blue reflection nebula. We expect stars to form from concentrated molecular clouds which look dark because of the presence of dust.

Take a look at this APOD from 2013 by Roberto Colombari, featuring the Pleiades:

M45: The Pleiades Star Cluster Credit & Copyright: Roberto Colombari

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The Pleiades have indeed just blundered into an unrelated dust cloud and lit it up. But the stars of the Pleiades are not young stellar objects. They are mature stars, about 100 million years old, and the brightest of the Pleiades are evolving off the main sequence.

Note, too, that although we can see a lot of dust in Roberto Colombari's image, there is no concentrated dark dust anywhere. There is nothing there that loks like a potential birthplace for stars.

But the Wolf's Cave Nebula looks like it might be just that.

Ann

[orin stepanek]

Ah; The wolf's cave! Is there a wolf star around? I don't Think wolves
live in a cave, thou I could be wrong! It Kinda; sorta, looks like a
bird to me ready to peck! I supose the birds eye would be the the
mouth of the cave! Can you see any wolves in it? Wolfs?

I noticed the Hartl name attached to this image; I have cousins with
that name!

[whatwhere]

Where is the wolf? Where is the cave?
If anything, I see a young penguin (white face, beak, trail of bubbles after a dive or upturn).

[whatwhere]

...Also an upswept wing. Almost uncanny, to be fair. Dare I say, un-canine!
But really, where is the wolf? Where is the cave?

[beryllium732]

The blue bright stars a top of the nebula are they also at the same 1400 light years distance?

[heehaw]

Ooops! Someone dropped a medical-test sample on that nice astronomical photograph

[johnnydeep]

...Also an upswept wing. Almost uncanny, to be fair. Dare I say, un-canine!
But really, where is the wolf? Where is the cave?

The "Wolf" here is just the last name of the astronomer who got the credit for his assistant's discovery. From the "Wolf's Cave" link in the description:

Max Wolf's assistant, August Kopff, photographically discovered the complex structure on October 21, 1908. To Wolf, it looked like a cave and he started calling it the Cave Nebula. Wolf also thought the nebula was an actual cave formation in the Milky Way stars. It was finally designated as vdB 152 and is still sometimes called Wolf's Cave.

Here is Max Wolf's Dec. 1908 announcement in the Monthly Notices of the Royal Astronomical Society, Vol. 69, p.117

[whatwhere]

...The "Wolf" here is just the last name of the astronomer who got the credit for his assistant's discovery. From the "Wolf's Cave" link in the description...

Well, now I feel silly! I've often been frustrated when I see people that don't read a post fully, including the links provided, then comment in ignorance! Somehow today was my turn. My own searches did not provide an answer. Apologies to all!

I must also express gratitude that someone (you) responded regardless!

I also see many posts that ask, "Where is the [insert name here]?" in the image, and no one cares to share. Though, I imagine so many that frequent this site, do actually know the answers.

Thank you!

P.S. I still don't see a cave!

[orin stepanek]

The "Wolf" here is just the last name of the astronomer who got the credit for his assistant's discovery. From the "Wolf's Cave" link in the description:

Max Wolf's assistant, August Kopff, photographically discovered the complex structure on October 21, 1908. To Wolf, it looked like a cave and he started calling it the Cave Nebula. Wolf also thought the nebula was an actual cave formation in the Milky Way stars. It was finally designated as vdB 152 and is still sometimes called Wolf's Cave.

Here is Max Wolf's Dec. 1908 announcement in the Monthly Notices of the Royal Astronomical Society, Vol. 69, p.117

[/quote]
Well; I must confess that I was looking for a Wolf Star! I even read the Max Wolf's Cave Nebula story! I still think it look's like a bird! I can also see a cave' with the bird's eye being the entrance of the cave!

[Ann]

The blue bright stars a top of the nebula are they also at the same 1400 light years distance?

The bright blue star at the top of the nebula, SAO 10287 or BD+69 1231, has a Gaia parallax of 2.6998 ± 0.0139 milliarcseconds, which puts it at a distance of ~1,200 light-years.

And yes, the nebula is at the same distance as the star, because it is the star that lights up the nebula.

The star, by the way, is not all that extremely bright. It is similar to Sirius in brightness, so that it is some ~21 times brighter than the Sun. Admittedly it would look a bit brighter if it wasn't surrounded by a nebula, because it has "lost" some light to the nebula by lighting it up. But it still isn't "super-bright".

Ann

[VictorBorun]

The blue bright stars a top of the nebula are they also at the same 1400 light years distance?

The bright blue star at the top of the nebula, SAO 10287 or BD+69 1231, has a Gaia parallax of 2.6998 ± 0.0139 milliarcseconds, which puts it at a distance of ~1,200 light-years.

And yes, the nebula is at the same distance as the star, because it is the star that lights up the nebula.

The star, by the way, is not all that extremely bright. It is similar to Sirius in brightness, so that it is some ~21 times brighter than the Sun. Admittedly it would look a bit brighter if it wasn't surrounded by a nebula, because it has "lost" some light to the nebula by lighting it up. But it still isn't "super-bright".

Ann

I wonder why the dusty tail is curved like Sun's protuberance of plasma and magnetic field lines.
Can it be a smooth rotation of the stellar wind as the giant stars were passing through the space at the top of this APOD? If those giants are moving right to left, the direction of tail-blowing was rotating counter-clockwise

[VictorBorun]

Note the small bluish gray lenticular cloud above the "head" (or the mouth?) of the Wolf Cave Nebula:

Lenticular clouds in the Earth's skies.

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Detail from APOD 15 November 2022.png

Lentcular clouds above the Wolf's Cave Nebula.

I am totally at lost trying to think of a reason how the interstellar gas can imitate a lenticular cloud in the wind trail above a mountain

[johnnydeep]

...The "Wolf" here is just the last name of the astronomer who got the credit for his assistant's discovery. From the "Wolf's Cave" link in the description...

Well, now I feel silly! I've often been frustrated when I see people that don't read a post fully, including the links provided, then comment in ignorance! Somehow today was my turn. My own searches did not provide an answer. Apologies to all!

I must also express gratitude that someone (you) responded regardless!

No problem. I try to answer the questions I can if no one else has done so already. "There are no silly questions" as my teachers used to say.

I also see many posts that ask, "Where is the [insert name here]?" in the image, and no one cares to share. Though, I imagine so many that frequent this site, do actually know the answers.

Thank you!

P.S. I still don't see a cave!

Yeah, I see no 'cave' either. Keep in mind that what people can see and imagine is highly dependent on the quality and resolving power of the optics used to take the image, as well as the particular filters used (if any) to restrict the output to specific wavelengths of light, and different optics can result in the emphasis (or even total absence) of radically different looking features. What might be evocative of a "wizard" or "flower" or "cave" in 1908, might be entirely lost in a modern image. And of course, sometimes, features simply get named after the discoverer.

[Ann]

WolfsCave_Lacroce_3053 -.jpg

Note the small bluish gray lenticular cloud above the "head" (or the mouth?) of the Wolf Cave Nebula:

Lenticular clouds in the Earth's skies.

---

Detail from APOD 15 November 2022.png

Lentcular clouds above the Wolf's Cave Nebula.

I am totally at lost trying to think of a reason how the interstellar gas can imitate a lenticular cloud in the wind trail above a mountain

Remember the Mandelbrot set? Where copies of the same shape are repeated at smaller and smaller (and maybe larger and larger) scales?

Click to view full size image

Maybe there are lenticular clouds above vdB 152 because there is a "wind trail" above a "mountain" below it - and that "mountain" is precisely the elongated cloud of gas and dust that is vdB 152?

Ann

[whatwhere]

Yeah, I see no 'cave' either. Keep in mind that what people can see and imagine is highly dependent on the quality and resolving power of the optics used to take the image, as well as the particular filters used (if any) to restrict the output to specific wavelengths of light, and different optics can result in the emphasis (or even total absence) of radically different looking features. What might be evocative of a "wizard" or "flower" or "cave" in 1908, might be entirely lost in a modern image. And of course, sometimes, features simply get named after the discoverer.

Yes! I don't imagine many people in 1908, let alone the few astronomers, had seen the underwater action of diving penguins. Otherwise it may very well have been named The Penguin!

[Fred the Cat]

WolfsCave_Lacroce_3053 -.jpg

Note the small bluish gray lenticular cloud above the "head" (or the mouth?) of the Wolf Cave Nebula:

Lenticular clouds in the Earth's skies.

---

Detail from APOD 15 November 2022.png

Lentcular clouds above the Wolf's Cave Nebula.

I am totally at lost trying to think of a reason how the interstellar gas can imitate a lenticular cloud in the wind trail above a mountain

Given an appetite for such things, I might label the nebula; " Jaws of a Sandworm".

Hungry for anything to spice up its existence.

On second thought, I don't think I " otter".

[Chris Peterson]

I am totally at lost trying to think of a reason how the interstellar gas can imitate a lenticular cloud in the wind trail above a mountain

Easy. Pareidolia.

[beryllium732]

The blue bright stars a top of the nebula are they also at the same 1400 light years distance?

The bright blue star at the top of the nebula, SAO 10287 or BD+69 1231, has a Gaia parallax of 2.6998 ± 0.0139 milliarcseconds, which puts it at a distance of ~1,200 light-years.

And yes, the nebula is at the same distance as the star, because it is the star that lights up the nebula.

The star, by the way, is not all that extremely bright. It is similar to Sirius in brightness, so that it is some ~21 times brighter than the Sun. Admittedly it would look a bit brighter if it wasn't surrounded by a nebula, because it has "lost" some light to the nebula by lighting it up. But it still isn't "super-bright".

Ann

Thank you! I wish there were a mouse clickable picture like the one the Deep Field pictures Hubble took so you can click on any galaxy and see the distance and redshift of it.

[starsurfer]

Beautiful image! I think this name comes from the fact it was identified by someone called Max Wolf. Also DeHt 5 actually is an example of a PN mimic.

[Ann]

Beautiful image! I think this name comes from the fact it was identified by someone called Max Wolf. Also DeHt 5 actually is an example of a PN mimic.

Thanks, starsurfer! I wanted you to chime in on DeHt 5. It didn't look like a "true" planetary to me.

Ann