APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

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APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by APOD Robot » Sun Feb 25, 2018 5:07 am

Image AE Aurigae and the Flaming Star Nebula

Explanation: Why is AE Aurigae called the flaming star? For one reason, the surrounding nebula IC 405 is named the Flaming Star Nebula because the region seems to harbor smoke, even though nothing is on fire, including interior star AE Aurigae. Fire, typically defined as the rapid molecular acquisition of oxygen, happens only when sufficient oxygen is present and is not important in such high-energy, low-oxygen environments. The material that appears as smoke is mostly interstellar hydrogen, but does contain smoke-like dark filaments of carbon-rich dust grains. The bright star AE Aurigae is visible near the nebula center and is so hot it is blue, emitting light so energetic it knocks electrons away from atoms in the surrounding gas. When an atom recaptures an electron, light is emitted creating the surrounding emission nebula. The Flaming Star nebula lies about 1,500 light years distant, spans about 5 light years, and is visible with a small telescope toward the constellation of the Charioteer (Auriga).

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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by Boomer12k » Sun Feb 25, 2018 6:11 am

Very nice Blue, and detail...

I am wondering if that was the star's "cocoon", and it is blowing it away, to show the blue butterfly that it is....

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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by Ann » Sun Feb 25, 2018 8:35 am

Boomer12k wrote:Very nice Blue, and detail...

I am wondering if that was the star's "cocoon", and it is blowing it away, to show the blue butterfly that it is....

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There is a lot of nice blue here indeed! :D
The Flaming Star Nebula in RGB.
Photo: Hunter Wilson.
AE Aurigae and the Flaming Star Nebula.
Photo: Martin Pugh.
























The color palette is a little unusual, and it can't be normally processed RGB. The picture at left shows the APOD, and the picture at right shows AE Aurigae and the Flaming Star Nebula in RGB (or possibly in HαRGB).

But I'm not complaining about today's APOD! It sure is beautiful! :D

As for your guess, Boomer, that the nebula might be the cocoon that the star is about to break out from... well, it depends on how you look at it. The nebula is not AE Aurigae's birth cocoon, that much is certain. AE Aurigae is a runaway star, rushing through space at breakneck speed, and the star has just run into a local cloud of gas and dust which it is lighting up as it is passing by. Look at the picture by Hunter Wilson. The red color of the nebula is the signature of ionized hydrogen and sulfur, and the brilliant ultraviolet light of AE Aurigae is responsible for ionizing the gas and making it shine red. The blue strands are tendrils of dust, lit up by the blue light of AE Aurigae.

So the Flaming Star Nebula is a combined emission and reflection nebula.

Ann
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De58te
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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by De58te » Sun Feb 25, 2018 11:32 am

Nice photo. I have a layman question. Apod robot says AE Auriga is the blue star near the centre of the nebula. Yet which one is AE, there are two blue stars which could be judged equally near the centre. (Three actually but I eliminate the third smaller one.) The upper one casts a lot of blue reflection light on the nebula as well, and looks slightly bigger, but the blue star that is in lower position seems to be making the lower nebula portion much brighter red than the upper. Having read before that emission nebulas are red then it seems to be that the lower blue star making the much brighter red emissions is AE Auriga?

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Ann
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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by Ann » Sun Feb 25, 2018 1:18 pm

De58te wrote:Nice photo. I have a layman question. Apod robot says AE Auriga is the blue star near the centre of the nebula. Yet which one is AE, there are two blue stars which could be judged equally near the centre. (Three actually but I eliminate the third smaller one.) The upper one casts a lot of blue reflection light on the nebula as well, and looks slightly bigger, but the blue star that is in lower position seems to be making the lower nebula portion much brighter red than the upper. Having read before that emission nebulas are red then it seems to be that the lower blue star making the much brighter red emissions is AE Auriga?
AE Aurigae is the brightest-looking star in the picture. (AE Aur is not only the brightest-looking star in the picture, but the intrinsically brightest star, as well.)

The "lower blue star" is not in any way responsible for the red nebula. That star is an F8-type star, probably no hotter than perhaps 6,500 K, which is way, way too cool to knock electrons of many hydrogen atoms into a "higher state of energy".

AE Aurigae, on the other hand, is an O9.5V-type star, and it may be as hot as 30,000 K. (In fact, according to Jim Kaler, AE Aur is as hot as 36,500 K.) The red light of the Flaming Star Nebula is all due to the fiercely energetic ultraviolet light of scorchingly hot AE Aurigae.

Ann
Last edited by Ann on Mon Feb 26, 2018 3:38 am, edited 1 time in total.
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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by jisles » Sun Feb 25, 2018 5:38 pm

AE Aurigae is not called the flaming star. The nebula is called the Flaming Star Nebula. "AE Aur is seen to light up the Flaming Star nebula, but it was not formed within it. Instead it is passing through the nebula at high speed and producing a violent bow shock and high energy electromagnetic radiation." - Wikipedia referencing López-Santiago, J.; Miceli, M.; Del Valle, M. V.; Romero, G. E.; Bonito, R.; Albacete-Colombo, J. F.; Pereira, V.; De Castro, E.; Damiani, F. (2012). "AE Aurigae: First Detection of Non-thermal X-Ray Emission from a Bow Shock Produced by a Runaway Star". The Astrophysical Journal Letters. 757: L6. arXiv:1208.6511 Freely accessible. Bibcode:2012ApJ...757L...6L. doi:10.1088/2041-8205/757/1/L6.
France, Kevin; McCandliss, Stephan R.; Lupu, Roxana E. (2007). "A Cometary Bow Shock and Mid-Infrared Emission Variations Revealed in Spitzer Observations of HD 34078 and IC 405". The Astrophysical Journal. 655 (2): 920. arXiv:astro-ph/0610953 Freely accessible. Bibcode:2007ApJ...655..920F. doi:10.1086/510481.

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Re: APOD: AE Aurigae and the Flaming Star Nebula (2018 Feb 25)

Post by alcor » Sun Feb 25, 2018 6:28 pm

It's not unusual that a star or a star cluster passes by a dark, dusty nebula. The Pleiades https://apod.nasa.gov/apod/ap171114.html is doing it too.
Click to play embedded YouTube video.
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AbDUCKtive reasoning

Post by neufer » Sun Feb 25, 2018 7:52 pm

jisles wrote:
AE Aurigae is not called the flaming star.

The nebula is called the Flaming Star Nebula.
https://en.wikipedia.org/wiki/Duck_test wrote:
<<The duck test is a form of abDUCtive reasoning. The test implies that a person can identify an unknown subject by observing that subject's habitual characteristics. It is sometimes used to counter abstruse, or even valid, arguments that something is not what it appears to be.

Indiana poet James Whitcomb Riley (1849–1916) may have coined the phrase when he wrote: When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.>>
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