APOD: Melotte 15 in the Heart Nebula (2024 Sep 17)

[APOD Robot]

Melotte 15 in the Heart Nebula

Explanation: Cosmic clouds form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are scattered in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrowband and broadband telescopic images, the view spans about 15 light-years and includes emission from ionized hydrogen, sulfur, and oxygen atoms mapped to green, red, and blue hues in the popular Hubble Palette. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - the Heart Nebula. IC 1805 is located about 7,500 light years away toward the boastful constellation Cassiopeia.

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[Ann]

Melotte 15 in the Heart Nebula Image Credit & Copyright: Richard McInnis

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What I find interesting about this image is that we can see large-scale structures in the shape of long twisted "tubes", and then there is a lot of small-scale turbulence inside those tubes.

What keeps the small-scale turbulence contained inside those long tubes?

Ann

[JohnD]

"Wider field images" may dub this the Heart Nebula, but I claim this bit as The British Isles!

[sc02492]

What I find interesting about this image is that we can see large-scale structures in the shape of long twisted "tubes", and then there is a lot of small-scale turbulence inside those tubes.

What keeps the small-scale turbulence contained inside those long tubes?

Ann

It's important to distinguish between true turbulence, which is a dynamic process involving chaotic changes in a fluid medium like liquid or gas, versus the illusion of turbulence created by the "static" signals used to create the image. I've become very fond of the Hubble Palette in the past several years because it creates interesting contrast changes within the image, when SII regions (red) merge into HII regions (green) to create yellow, for instance. When you actually process these images and see them blossom right before your eyes on the computer screen, it's really quite amazing and aesthetically pleasing. However, I have always interpreted this appearance as a static phenomenon representing the mapping of various regions of emission (SII, HII, OIII), as opposed to having anything to do with "turbulence".

[AVAO]

What I find interesting about this image is that we can see large-scale structures in the shape of long twisted "tubes", and then there is a lot of small-scale turbulence inside those tubes.

What keeps the small-scale turbulence contained inside those long tubes?

Ann

It's important to distinguish between true turbulence, which is a dynamic process involving chaotic changes in a fluid medium like liquid or gas, versus the illusion of turbulence created by the "static" signals used to create the image. I've become very fond of the Hubble Palette in the past several years because it creates interesting contrast changes within the image, when SII regions (red) merge into HII regions (green) to create yellow, for instance. When you actually process these images and see them blossom right before your eyes on the computer screen, it's really quite amazing and aesthetically pleasing. However, I have always interpreted this appearance as a static phenomenon representing the mapping of various regions of emission (SII, HII, OIII), as opposed to having anything to do with "turbulence".

Thank you for your very exciting and informative input. But I think there is a misunderstanding here. Ann tried to describe his visual perception. However, speaking of turbulence is probably a somewhat unfortunate description. Normally, this is used to characterise chaotic substructures. In this case, it probably means fragmented substructures within the very clearly visible helical main filament structures. In other wavelengths, such as in the IR, other characteristics emerge.

Click to view full size image 1 or image 2

Original data: NASA/ESA DSS2/HERSCHEL

Click to view full size image

Original data: NASA/ESA SST/ALLWISE

[Ann]

What I find interesting about this image is that we can see large-scale structures in the shape of long twisted "tubes", and then there is a lot of small-scale turbulence inside those tubes.

What keeps the small-scale turbulence contained inside those long tubes?

Ann

It's important to distinguish between true turbulence, which is a dynamic process involving chaotic changes in a fluid medium like liquid or gas, versus the illusion of turbulence created by the "static" signals used to create the image. I've become very fond of the Hubble Palette in the past several years because it creates interesting contrast changes within the image, when SII regions (red) merge into HII regions (green) to create yellow, for instance. When you actually process these images and see them blossom right before your eyes on the computer screen, it's really quite amazing and aesthetically pleasing. However, I have always interpreted this appearance as a static phenomenon representing the mapping of various regions of emission (SII, HII, OIII), as opposed to having anything to do with "turbulence".

Thank you for your very exciting and informative input. But I think there is a misunderstanding here. Ann tried to describe his visual perception. However, speaking of turbulence is probably a somewhat unfortunate description. Normally, this is used to characterise chaotic substructures. In this case, it probably means fragmented substructures within the very clearly visible helical main filament structures. In other wavelengths, such as in the IR, other characteristics emerge.

Click to view full size image 1 or image 2

Original data: NASA/ESA DSS2/HERSCHEL

Click to view full size image

Original data: NASA/ESA SST/ALLWISE

Thanks, Jac! Yes indeed, I used the wrong word here. The substructures are fragmented, not chaotic.

Ann

P.S. I'm a woman.

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Maybe not quite so grumpy!