APOD: NGC 1499: The California Nebula (2022 Oct 22)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 4898
Joined: Fri Dec 04, 2009 3:27 am

APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by APOD Robot » Sat Oct 22, 2022 4:05 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 star Xi Persei just to the right of the nebula. A popular target for astrophotographers, this deep image reveals the glowing nebula, obscuring dust, and stars across a 3 degree wide field of view. The California nebula lies toward the constellation Perseus, not far from the Pleiades.

<< Previous APOD This Day in APOD Next APOD >>

User avatar
VictorBorun
Commander
Posts: 729
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by VictorBorun » Sat Oct 22, 2022 5:20 am

it's where our earthly experience with depth and illumination may be working well

User avatar
Ann
4725 Å
Posts: 12464
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by Ann » Sat Oct 22, 2022 5:48 am

20221011NGC1499CaliforniaNebula1024[1].jpg
NGC 1499: The California Nebula
Image Credit & Copyright: Stephen Kennedy

Today's APOD is a fine picture that brings out the two-ridge nature of the California Nebula. Possible runaway O7.5III-type star Menkib, Xi Persei (the only O-type star in constellation Perseus) has been plowing into higher-than-average density gas and pushing it and compressing it like a snowplow. The intense ultraviolet radiation of hot Xi Per ionizes the compressed gas and makes it glow red. Menkib is seen at upper center right in the APOD.

As a blue-loving Color Commentator, I was of course disappointed at the absolutely non-blue, almost egg-white appearance of Menkib. Yes, Menkib is certainly reddened dust, but its "apparent color" is almost as blue as Vega. I started hunting around for a picture that would appeal more to my color sensitivities and found a picture by Scott Rosen:

California Nebula Pleiades Scott Rosen.png
California Nebula and Pleiades widefield. Photo: Scott Rosen.


Do click the image to see the full size of Scott Rosen's image. I have annotated it and drawn the contours of the darkest and thickest dust in the vicinity. (And if you're wondering: Yes, Scott Rosen's image is "up-and-down"-reversed.)
Wikipedia wrote about Xi Per, the star ionizing the California Nebula:

The star has a mass of some 30 solar masses and a surface temperature of 35,000 kelvins, making it one of the hottest stars that can be seen with the naked eye. The fluorescence of the California Nebula (NGC 1499) is due to this star's prodigious radiation. It is a member of the Perseus OB2 association of co-moving stars, but may be a runaway star since it is now separated by 200 pc from the association's center and has an unusually high radial velocity.

I guess that the center of Perseus OB2 association of co-moving stars is near bright B1-type giants Zeta and Omicron Persei.


IC 348 near Omicron Persei is the only site of star formation in constellation Perseus, at least to my knowledge, and it may be the center of Perseus OB2. Xi Persei may have been born not far from IC 348 and then received a kick out of the association center so that it plowed a "double ridge of gas" in front of it, creating the California Nebula, and bathed it in ultraviolet light and made it glow red.


But, okay! I should have clicked on all the links in today's APOD caption to find the best portrait of the California Nebula, the Pleiades and IC 348. Here it is, by Rogelio Bernal Andreo! :D

Ann
You do not have the required permissions to view the files attached to this post.
Color Commentator

User avatar
AVAO
Science Officer
Posts: 217
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by AVAO » Sat Oct 22, 2022 8:37 am

Ann wrote: Sat Oct 22, 2022 5:48 am
But, okay! I should have clicked on all the links in today's APOD caption to find the best portrait of the California Nebula, the Pleiades and IC 348. Here it is, by Rogelio Bernal Andreo! :D

Ann
Why isn't there a red glow at the Pleiades?
Like Xi Persei, these are very bright and also radiate strongly in the X-ray.

User avatar
VictorBorun
Commander
Posts: 729
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by VictorBorun » Sat Oct 22, 2022 10:05 am

AVAO wrote: Sat Oct 22, 2022 8:37 am
Ann wrote: Sat Oct 22, 2022 5:48 am
But, okay! I should have clicked on all the links in today's APOD caption to find the best portrait of the California Nebula, the Pleiades and IC 348. Here it is, by Rogelio Bernal Andreo! :D

Ann
Why isn't there a red glow at the Pleiades?
Like Xi Persei, these are very bright and also radiate strongly in the X-ray.
My first thought is: you need a bulldozer of a star, i. e. massive and moving, to pile enough interstellar gas in this region.

By the way, it's not often that a massive star is kicked out of a stellar cluster. Mostly if two stars happen to interact closely, it's less massive of the two that soars and more massive one that sinks

User avatar
Ann
4725 Å
Posts: 12464
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by Ann » Sat Oct 22, 2022 10:15 am

AVAO wrote: Sat Oct 22, 2022 8:37 am
Ann wrote: Sat Oct 22, 2022 5:48 am
But, okay! I should have clicked on all the links in today's APOD caption to find the best portrait of the California Nebula, the Pleiades and IC 348. Here it is, by Rogelio Bernal Andreo! :D

Ann
Why isn't there a red glow at the Pleiades?
Like Xi Persei, these are very bright and also radiate strongly in the X-ray.
The Pleiades are way too cool to ionize a red emission nebula! The brightest and hottest of them are spectral classes B6-B8. That is to say that their temperatures are likely below 16,000 K. The temperature of Menkib, Xi Per, which ionizes the California Nebula, is 35,000 K.

To ionize a nebula, a star has to be at least spectral class B1. A star that could have ionized a nebula if there had been any significant amounts of gas in its vicinity is Beta Cephei, Alfirk. Its temperature is 27,000 K.

A star that is a little cooler than Beta Cephei, so that it just borderline barely ionizes parts of its nebula, is HD 200775, a young star of spectral class B2. It is surrounded by a lot of blue reflection nebulosity and a hint of pink Hα emission nebulosity in its own nebula, the Iris Nebula:

Beta Cep and constellation Cepheus Will Gater.png
Beta Cephei in constellation Cepheus by Will Gater.
Iris Nebula Adam Block annotated.png
The Iris Nebula and star HD 200775. The arrows point at weakly ionized regions.
I don't remember why I put the question mark there. Photo: Adam Block.

A star of spectral class B1 that does ionize a red emission nebula is BD+46 3474, ionizing star of the Cocoon Nebula:


Also it is not X-rays that ionize hydrogen and make it glow red. It is ultraviolet light, which is emitted in copious amounts by stars whose temperature is around 30,000 K and higher.

Ann
You do not have the required permissions to view the files attached to this post.
Color Commentator

User avatar
orin stepanek
Plutopian
Posts: 7883
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by orin stepanek » Sat Oct 22, 2022 1:18 pm

20221011NGC1499CaliforniaNebula1024.jpg
Sun and California both in Orion arm! I never noticed that before! I
learned something! 8-) Can it be seen with the naked eye? I'll look
for it when I view the 7 sisters! :wink:
You do not have the required permissions to view the files attached to this post.
Last edited by orin stepanek on Sun Oct 23, 2022 1:58 am, edited 2 times in total.
Orin

Smile today; tomorrow's another day!

User avatar
AVAO
Science Officer
Posts: 217
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by AVAO » Sat Oct 22, 2022 1:29 pm

Ann wrote: Sat Oct 22, 2022 10:15 am
AVAO wrote: Sat Oct 22, 2022 8:37 am
Why isn't there a red glow at the Pleiades?
Like Xi Persei, these are very bright and also radiate strongly in the X-ray.
The Pleiades are way too cool to ionize a red emission nebula! The brightest and hottest of them are spectral classes B6-B8. That is to say that their temperatures are likely below 16,000 K. The temperature of Menkib, Xi Per, which ionizes the California Nebula, is 35,000 K.

To ionize a nebula, a star has to be at least spectral class B1. A star that could have ionized a nebula if there had been any significant amounts of gas in its vicinity is Beta Cephei, Alfirk. Its temperature is 27,000 K.

A star that is a little cooler than Beta Cephei, so that it just borderline barely ionizes parts of its nebula, is HD 200775, a young star of spectral class B2. It is surrounded by a lot of blue reflection nebulosity and a hint of pink Hα emission nebulosity in its own nebula, the Iris Nebula:

Beta Cep and constellation Cepheus Will Gater.png
Beta Cephei in constellation Cepheus by Will Gater.
Iris Nebula Adam Block annotated.png
The Iris Nebula and star HD 200775. The arrows point at weakly ionized regions.
I don't remember why I put the question mark there. Photo: Adam Block.

A star of spectral class B1 that does ionize a red emission nebula is BD+46 3474, ionizing star of the Cocoon Nebula:


Also it is not X-rays that ionize hydrogen and make it glow red. It is ultraviolet light, which is emitted in copious amounts by stars whose temperature is around 30,000 K and higher.

Ann
ThanX Ann

I was sure, you had a good answer to that.
Your explanations are always so helpful!

Jac

User avatar
Cousin Ricky
Science Officer
Posts: 408
Joined: Mon Aug 26, 2013 4:08 pm
Location: St. Thomas, U.S. Virgin Islands (+18.3, -64.9)

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by Cousin Ricky » Sat Oct 22, 2022 2:14 pm

APOD Robot wrote: Sat Oct 22, 2022 4:05 am The California Nebula shines with the telltale reddish glow characteristic of hydrogen atoms recombining with long lost electrons... Most likely providing the energetic starlight that ionizes much of the nebular gas is the bright, hot star Xi Persei just to the right of the nebula.
This means that this star can ionize gas up to 50 light years away! :shock: That is impressive.

User avatar
AVAO
Science Officer
Posts: 217
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by AVAO » Sat Oct 22, 2022 2:41 pm

Ann wrote: Sat Oct 22, 2022 5:48 am IC 348 near Omicron Persei is the only site of star formation in constellation Perseus, at least to my knowledge, and it may be the center of Perseus OB2. Xi Persei may have been born not far from IC 348 and then received a kick out of the association center so that it plowed a "double ridge of gas" in front of it, creating the California Nebula, and bathed it in ultraviolet light and made it glow red.

Ann

Bold hypothesis. But yeah, there seems to be a lot (star formation) going on at IC 348 :roll:

Area in Mid-IR:
Image

Core of IC 348 in different IR-wavelenghts (WISE/HERSCHEL):
Image
jac berne (flickr)

User avatar
Ann
4725 Å
Posts: 12464
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by Ann » Sat Oct 22, 2022 3:29 pm

AVAO wrote: Sat Oct 22, 2022 2:41 pm
Ann wrote: Sat Oct 22, 2022 5:48 am IC 348 near Omicron Persei is the only site of star formation in constellation Perseus, at least to my knowledge, and it may be the center of Perseus OB2. Xi Persei may have been born not far from IC 348 and then received a kick out of the association center so that it plowed a "double ridge of gas" in front of it, creating the California Nebula, and bathed it in ultraviolet light and made it glow red.

Ann

Bold hypothesis. But yeah, there seems to be a lot (star formation) going on at IC 348 :roll:
Isn't speculating fun? :) :D

Ann
Color Commentator

DL MARTIN

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by DL MARTIN » Sat Oct 22, 2022 4:57 pm

By placing the California Nebula in the Orion Arm 1500 light-years from the Sun, I've newly appreciated why distance can be independent of time past. Thank you. Some of us just take a little longer.

User avatar
Ann
4725 Å
Posts: 12464
Joined: Sat May 29, 2010 5:33 am

Re: APOD: NGC 1499: The California Nebula (2022 Oct 22)

Post by Ann » Sat Oct 22, 2022 5:55 pm

AVAO wrote: Sat Oct 22, 2022 2:41 pm
Ann wrote: Sat Oct 22, 2022 5:48 am IC 348 near Omicron Persei is the only site of star formation in constellation Perseus, at least to my knowledge, and it may be the center of Perseus OB2. Xi Persei may have been born not far from IC 348 and then received a kick out of the association center so that it plowed a "double ridge of gas" in front of it, creating the California Nebula, and bathed it in ultraviolet light and made it glow red.

Ann

Bold hypothesis. But yeah, there seems to be a lot (star formation) going on at IC 348 :roll:

Area in Mid-IR:
Image

Core of IC 348 in different IR-wavelenghts (WISE/HERSCHEL):
Image
jac berne (flickr)

I was wrong!!! :oops: IC 348 is not the only place where stars are forming in Perseus, because NGC 1333 is a well-known site of star formation in in this part of the sky!

Wikipedia wrote about NGC 1333:
The nebula region has a combined mass of approximately 450 M☉,[4] while the cluster contains around 150 stars with a median age of a million years and a combined mass of 100 M☉. The average star formation rate is 10×10−4 M☉ yr–1.[4] Within the nebular are 20 young stellar objects producing outflows, including Herbig–Haro objects. A total of 95 X-ray sources that are associated with known members of embedded star clusters.[6] In 2011 researchers reported finding 30 to 40 brown dwarf objects in the cloud and in the Rho Ophiuchi cloud complex.
Wikipedia wrote:
IC 348 is a star-forming region in the constellation Perseus located about 315 parsecs from the Sun. It consists of nebulosity and an associated 2-million-year-old cluster of roughly 400 stars within an angular diameter of 20″. The most massive stars in the cluster are the binary star system BD+31°643, which has a combined spectral class of B5.[3] Based upon infrared observations using the Spitzer Space Telescope, about half of the stars in the cluster have a circumstellar disk, of which 60% are thick or primordial disks.[4]

The age of this cluster has allowed three low mass brown dwarfs to be discovered. These objects lose heat as they age, so they are more readily discovered while they are still young.

At least IC 348 seems to be a more massive site of star formation than NGC 1333, with more stars and more massive stars forming there than in NGC 1333.

Then again, Perseus is located in the major Perseus arm of our galaxy, so clearly there is a lot more star formation there than just NGC 1333 and IC 348! Obviously! Where is the "slap-face, I'm-an-idiot" smiley? Okay, this one? :facepalm:

Ann
Color Commentator