Page 1 of 1
APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 4:06 am
by APOD Robot
NGC 604: Giant Stellar Nursery
Explanation: Located some 3 million light-years away in the arms of nearby spiral
galaxy M33, giant stellar nursery
NGC 604 is about 1,300 light-years across. That's nearly 100 times the size of the Milky Way's
Orion Nebula, the closest large star forming region to planet Earth. In fact, among the star forming regions within the Local Group of galaxies, NGC 604 is second in size only to 30 Doradus, also known as
the Tarantula Nebula in the Large Magellanic Cloud. Cavernous bubbles and cavities in NGC 604 fill this stunning infrared image from the
James Webb Space Telescope's NIRCam. They are carved out by energetic stellar winds from the region's more than 200 hot, massive, young stars, all still in early
stages of their lives.
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 5:07 am
by Ann
I have two favorite images of NGC 604. Today's APOD is not one of them.
Let's start with the Chandra portrait of NGC 604:
Possible location of the Chandra bubbles in the APOD.
Maybe it's just the right-hand bubble that is seen in the Chandra image.
Chandra X-ray Observatory wrote:
This composite image from Chandra X-ray Observatory data (colored blue), combined with optical light data from the Hubble Space Telescope (red and green), shows a divided neighborhood where some 200 hot, young, massive stars reside.
However, there is a difference between the two sides of this bifurcated stellar city. On the western (right) side, the amount of hot gas found in the bubbles corresponds to about 4300 times the mass of the sun. This value and the brightness of the gas in X-rays imply that the western part of NGC 604 is entirely powered by winds from the 200 hot massive stars.
The situation is different on the eastern (left) side of NGC 604. On this side, the X-ray gas contains 1750 times the mass of the sun and winds from young stars cannot explain the brightness of the X-ray emission. The bubbles on this side appear to be much older and were likely created and powered by young stars and supernovas in the past.
Wow! We are witnessing how star formation is progressing from one part of a giant molecular cloud to another.
All right! My second favorite picture of NGC 604 is one by Hubble:
I was disappointed when I first saw the Hubble portrait of M33, because I thought that the picture was so overwhelmingly yellow and monotonous. I was used to seeing M33 with a lot of blue stars and pink nebulas, the way it looks in the picture by Adam Block... wait... what's that tiny blue object at upper right in the Hubble image?
It's NGC 604! It is!
The Hubble picture really puts NGC 604 in its place. It is so small compared with M33 itself, but it stands out incredibly.
Ann
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 2:37 pm
by Christian G.
I'm still somewhat puzzled by JWST colour choices. Is there a scientific reason why they chose pink/red for NGC 604 but a kind of rusty brownish not-really-red for the Tarantula Nebula? Is it to reflect different molecular properties or are these different colours for no real reason?
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 2:54 pm
by Chris Peterson
Christian G. wrote: ↑Thu Apr 25, 2024 2:37 pm
I'm still somewhat puzzled by JWST colour choices. Is there a scientific reason why they chose pink/red for NGC 604 but a kind of rusty brownish not-really-red for the Tarantula Nebula? Is it to reflect different molecular properties or are these different colours for no real reason?
604.png
2070.jpg
Where did you find the Tarantula image? (And to me, it looks like both the images you provided are using the same palette.)
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 3:19 pm
by Christian G.
Chris Peterson wrote: ↑Thu Apr 25, 2024 2:54 pm
Christian G. wrote: ↑Thu Apr 25, 2024 2:37 pm
I'm still somewhat puzzled by JWST colour choices. Is there a scientific reason why they chose pink/red for NGC 604 but a kind of rusty brownish not-really-red for the Tarantula Nebula? Is it to reflect different molecular properties or are these different colours for no real reason?
604.png
2070.jpg
Where did you find the Tarantula image? (And to me, it looks like both the images you provided are using the same palette.)
I found it here:
https://www.nasa.gov/universe/a-cosmic- ... asas-webb/
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 3:55 pm
by Chris Peterson
Christian G. wrote: ↑Thu Apr 25, 2024 3:19 pm
Chris Peterson wrote: ↑Thu Apr 25, 2024 2:54 pm
Christian G. wrote: ↑Thu Apr 25, 2024 2:37 pm
I'm still somewhat puzzled by JWST colour choices. Is there a scientific reason why they chose pink/red for NGC 604 but a kind of rusty brownish not-really-red for the Tarantula Nebula? Is it to reflect different molecular properties or are these different colours for no real reason?
604.png
2070.jpg
Where did you find the Tarantula image? (And to me, it looks like both the images you provided are using the same palette.)
I found it here:
https://www.nasa.gov/universe/a-cosmic- ... asas-webb/
It's unclear what mapping was used in either image, or indeed, which filters. As a rule, color images have little scientific value. They are created for press releases and education, not science. So the choice of colors is often aesthetic, or intended to emphasize particular structure. This is particularly true where some or all of the data is completely outside the human visual spectrum, and where more than three filters are used.
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 5:19 pm
by AVAO
Chris Peterson wrote: ↑Thu Apr 25, 2024 3:55 pm
It's unclear what mapping was used in either image, or indeed, which filters. As a rule, color images have little scientific value. They are created for press releases and education, not science. So the choice of colors is often aesthetic, or intended to emphasize particular structure. This is particularly true where some or all of the data is completely outside the human visual spectrum, and where more than three filters are used.
Chris' comments are certainly correct.
In addition, simply add the following information:
The filters F090W, F200W, F335M, F444W were used for both images.
In the image of NGC 604, F187N (cyan) and F470N (intense red) were also used,
which is why the inner clouds turn into white-blue and the outer clouds turn into intense red.
In fact, the pictures are not really comparable...
...I love this treasure chest far away...
jac berne (flickr) artistic composit, mixed sources
Re: APOD: NGC 604: Giant Stellar Nursery (2024 Apr 25)
Posted: Thu Apr 25, 2024 7:04 pm
by VictorBorun
Ann wrote: ↑Thu Apr 25, 2024 5:07 am
Let's start with my Chandra portrait of NGC 604:
APOD 25 April 2024 annotated.png
Possible location of the Chandra bubbles in the APOD.
Maybe it's just the right-hand bubble that is seen in the Chandra image.
Chandra X-ray Observatory wrote:
This composite image from Chandra X-ray Observatory data (colored blue), combined with optical light data from the Hubble Space Telescope (red and green), shows a divided neighborhood where some 200 hot, young, massive stars reside.
However, there is a difference between the two sides of this bifurcated stellar city. On the western (right) side, the amount of hot gas found in the bubbles corresponds to about 4300 times the mass of the sun. This value and the brightness of the gas in X-rays imply that the western part of NGC 604 is entirely powered by winds from the 200 hot massive stars.
The situation is different on the eastern (left) side of NGC 604. On this side, the X-ray gas contains 1750 times the mass of the sun and winds from young stars cannot explain the brightness of the X-ray emission. The bubbles on this side appear to be much older and were likely created and powered by young stars and supernovas in the past.
Wow! We are witnessing how star formation is progressing from one part of a giant molecular cloud to another.
Ann
your
Possible location of the Chandra bubbles in the APOD fits just fine