APOD: NGC 1499: The California Nebula (2019 Aug 23)

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APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by APOD Robot » Fri Aug 23, 2019 4:07 am

Image NGC 1499: The California Nebula

Explanation: Drifting through the Orion Arm of the spiral Milky Way Galaxy, this cosmic cloud by chance echoes the outline of California on the west coast of the United States. Our own Sun also lies within the Milky Way's Orion Arm, only about 1,500 light-years from the California Nebula. Also known as NGC 1499, the classic emission nebula is around 100 light-years long. The California Nebula shines with the telltale reddish glow characteristic of hydrogen atoms recombining with long lost electrons. The electrons have been stripped away, ionized by energetic starlight. Most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot, bluish star Xi Persei just to the right of the nebula. A popular target for astrophotographers, this deep California Nebula image is a 6 panel telescopic mosaic and covers a wide field of view. The nebula lies toward the constellation Perseus, not far from the Pleiades.

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Ann
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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by Ann » Fri Aug 23, 2019 5:53 am

First of all, thank you Sara Wager for a gorgeous portrait of the California Nebula! :D I love "true-color" (RGB or RGB + Hα) astro images, and I love the shades of reddish-pink and blue that I can see in your picture. Also, the fact that yours is such a deep and wide-angle picture allows us to see more of the California Nebula.

I would have loved to paste your image into my own post, but I can't, since it is too big. So I will post another image of the California Nebula next to a picture of the Flaming Star Nebula, because I think that these two nebulas (and their ionizing stars) are very interestingly similar yet different at the same time.

The Flaming Star Nebula. Photo: Rolf Geissinger.
The California Nebula. Photo: Hytham Abu-Safieh.

























In the California Nebula, an O-type runaway star is piling up a nebula in front of it, a nebula with two shock fronts of piled-up ionized gas. In the Flaming Star Nebula, the star has overtaken the nebula and slammed into it, causing chaotic ripples in the nebula.

Note the long tail of fainter nebulosity at right in the Flaming Star Nebula. Note, in the Sara Wager image in today's APOD, that you can see a faint "tail" (at upper right) in the California Nebula, too.

The two ionizing stars, Xi Persei and AE Aurigae, are also interestingly similar. Both are runaway O-type stars, but Xi Persei is a bit hotter, heavier, brighter and more evolved.

Ann
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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by orin stepanek » Fri Aug 23, 2019 11:15 am

I'm not too bright; but with all that dust; I'd expect the California Nebula to be a star forming region! :?
Orin

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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by neufer » Fri Aug 23, 2019 12:14 pm

orin stepanek wrote:
Fri Aug 23, 2019 11:15 am

with all that dust; I'd expect the California Nebula to be a star forming region! :?
  • Not so much these days:
https://en.wikipedia.org/wiki/Cinema_of_the_United_States#Decline_of_the_studio_system_(late_1940s) wrote:
During the Golden Age of Hollywood, which lasted from the end of the silent era in American cinema in the late 1920s to the early 1960s, thousands of movies were issued from the Hollywood studios. The studio system and the Golden Age of Hollywood succumbed to two forces that developed in the late 1940s:
  • 1) a federal antitrust action that separated the production of films from their exhibition;
    and 2) the advent of television.
Art Neuendorffer

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Ann
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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by Ann » Fri Aug 23, 2019 3:03 pm

orin stepanek wrote:
Fri Aug 23, 2019 11:15 am
I'm not too bright; but with all that dust; I'd expect the California Nebula to be a star forming region! :?
The California Nebula in infrared light. Photo: WISE.
Some low-mass stars may form in the California Nebula, but I strongly doubt that the California is a very fertile star-spawning region. It looks just too "thin" to me to give birth to a lot of stars!

If stars are born in the California Nebula, they are likely born in the two parallel ridges of piled-up gas and dust which are colored green in the image from WISE.

Ionizing star Menkib, Xi Persei, can be seen at upper left. The red patch in front of it is shock wave of gas that has been ionized by the runaway star.

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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by Psnarf » Fri Aug 23, 2019 3:11 pm

Sew! this is a huge region of protons? A stream of electrons from Xi Persei zipping through the cloud of widely separated protons fall into the protons releasing the photons we detect? Fascinating! Once captured, do incoming electrons then transfer enough of their energy to the captured electrons, knocking them into the next higher energy level only to fall back releasing another photon?
-Mebrain Hertz

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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by starsurfer » Fri Aug 23, 2019 4:28 pm

APOD Robot wrote:
Fri Aug 23, 2019 4:07 am
is a 6 panel telecopic mosaic and covers a wide field of view.
Should say telescopic.

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Re: APOD: NGC 1499: The California Nebula (2019 Aug 23)

Post by Chris Peterson » Fri Aug 23, 2019 5:04 pm

Psnarf wrote:
Fri Aug 23, 2019 3:11 pm
Sew! this is a huge region of protons? A stream of electrons from Xi Persei zipping through the cloud of widely separated protons fall into the protons releasing the photons we detect? Fascinating! Once captured, do incoming electrons then transfer enough of their energy to the captured electrons, knocking them into the next higher energy level only to fall back releasing another photon?
-Mebrain Hertz
Photons from the star ionize the hydrogen, either raising electrons into higher shells, or knocking them away completely (leaving free protons). When those electrons recombine with the protons we get different wavelengths of light released, including the h-alpha emissions typically captured in astronomical images.
Chris

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