APOD: Clouds of the Carina Nebula (2021 May 02)

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APOD: Clouds of the Carina Nebula (2021 May 02)

Post by APOD Robot » Sun May 02, 2021 4:05 am

Image Clouds of the Carina Nebula

Explanation: What forms lurk in the mists of the Carina Nebula? The dark ominous figures are actually molecular clouds, knots of molecular gas and dust so thick they have become opaque. In comparison, however, these clouds are typically much less dense than Earth's atmosphere. Featured here is a detailed image of the core of the Carina Nebula, a part where both dark and colorful clouds of gas and dust are particularly prominent. The image was captured in mid-2016 from Siding Spring Observatory in Australia. Although the nebula is predominantly composed of hydrogen gas -- here colored green, the image was assigned colors so that light emitted by trace amounts of sulfur and oxygen appear red and blue, respectively. The entire Carina Nebula, cataloged as NGC 3372, spans over 300 light years and lies about 7,500 light-years away in the constellation of Carina. Eta Carinae, the most energetic star in the nebula, was one of the brightest stars in the sky in the 1830s, but then faded dramatically.

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Ann
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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by Ann » Sun May 02, 2021 6:06 am

As some of you may know, I'm not the greatest fan of the aesthetic qualities of Hubble palette images (even if I do realize that such images can provide important information on the elements found in a nebula - and also they are much easier to acquire with amateur equipment under light-polluted skies than RGB images).

Even so, just for comparison, I'm going to post a few RGB (or mostly RGB) images of the Carina Nebula! :D


The Hubble palette image at top left is sharply green and orange-red due to the fact that the ubiquitous Hydrogen Alpha is mapped as green, and the pseudo-green of Hα and the red of SII combine to make sharply orange hues.

The ESO image looks strikingly blue. That is probably because an ultraviolet filter has been used for this image (as well as B,V, R, Hα and SII filters). There must be a lot of ultraviolet light in the Carina Nebula, and when UV is mapped as blue, the V-shaped highly ionized part of the Carina Nebula is likely to take on a bluish cast.

The picture by Maicon Germiniani is the one that is by far the most visually appealing to me. I find the the image as beautiful as if it had been a painting by an abstract colorist. Maicon Germiniani describes some technical details about the making of his image on this page, but as far as I can understand, this is an LRGB image. No Hα filter has been used, and no UV.

Harel Boren's image at bottom right looks almost "all red". Like Maicon Germiniani's image, Harel Boren's picture is, I believe, an LRGB image. But while Maicon Germiniani's image is rich in colors, Harel Boren's is, indeed, almost all red.

I believe that Harel Boren is right. The Carina Nebula is overwhelmingly dominated by hydrogen alpha light, which is indeed very red. But even in a red nebula there are some small variations in hue as well as in brightness.


Finally, at top right in Harel Boren's image, Chilean poet Gabriela Mistral is surveying the skies from her own private nebula, the Gabriela Mistral Nebula or NGC 3324.

Why does the nebula look so yellow in the picture I have posted at left? It does not look yellow at all in Harel Boren's image.

Well, check out this page. The yellow color is due to the fact that the 660 nm filter, which would normally be shown as red (since light of a wavelength of 660 nm is red), has been mapped as bright yellow in the ESO image.

There you go. Filters, filters. Mapping, mapping. Processing, processing.

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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by orin stepanek » Sun May 02, 2021 12:06 pm

280px-Eta_Carinae.jpg
Is Eta Carinae a double star?
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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by Chris Peterson » Sun May 02, 2021 1:03 pm

orin stepanek wrote:
Sun May 02, 2021 12:06 pm
280px-Eta_Carinae.jpg

Is Eta Carinae a double star?
Yes, it is a system of two very massive stars.
Chris

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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by johnnydeep » Sun May 02, 2021 7:36 pm

Chris Peterson wrote:
Sun May 02, 2021 1:03 pm
orin stepanek wrote:
Sun May 02, 2021 12:06 pm
280px-Eta_Carinae.jpg

Is Eta Carinae a double star?
Yes, it is a system of two very massive stars.
Interestingly (or not), the WikiPedia page begins by saying it is composed of at least two stars, but there's no further mention that it might have additional stellar members that I can find. I guess this means that the only definitive thing we can say at this point is that there are definitely two large components.
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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by VictorBorun » Sun May 02, 2021 9:41 pm

orin stepanek wrote:
Sun May 02, 2021 12:06 pm
280px-Eta_Carinae.jpg
Is Eta Carinae a double star?
Will some one please help me see this Eta Carinae butterfly thing in the posted pic?

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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by Ann » Mon May 03, 2021 5:05 am

VictorBorun wrote:
Sun May 02, 2021 9:41 pm
orin stepanek wrote:
Sun May 02, 2021 12:06 pm
280px-Eta_Carinae.jpg
Is Eta Carinae a double star?
Will some one please help me see this Eta Carinae butterfly thing in the posted pic?

You can't see it, because Eta Carina itself is so bright that the Homunculus Nebula (the "butterfly thing") is totally overexposed in the APOD.

At right you can see an infrared image of the Homunculus Nebula, taken with the NACO near-infrared adaptive optics instrument on ESO's Very Large Telescope. At infrared wavelengths, the blisteringly hot stars of Eta Carina look fainter than they do in optical light, and the surrounding nebula can be seen.

Note that the Homunculus Nebula does not look exactly the same in the picture in the ESO image, the one I posted here, as it does in the Hubble image earlier in the thread. The two images were made with different telescopes using different filters.

Go to this page to see higher resolved versions of the ESO mosaic that I posted here.

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Re: APOD: Clouds of the Carina Nebula (2021 May 02)

Post by VictorBorun » Fri May 07, 2021 8:51 am

cool!