Starship Asterisk*

Stardust in Perseus

Explanation: This cosmic expanse of dust, gas, and stars covers some 6 degrees on the sky in the heroic constellation Perseus. At upper left in the gorgeous skyscape is the intriguing young star cluster IC 348 and neighboring Flying Ghost Nebula with clouds of obscuring interstellar dust cataloged as Barnard 3 and 4. At right, another active star forming region NGC 1333 is connected by dark and dusty tendrils on the outskirts of the giant Perseus Molecular Cloud, about 850 light-years away. Other dusty nebulae are scattered around the field of view, along with the faint reddish glow of hydrogen gas. In fact, the cosmic dust tends to hide the newly formed stars and young stellar objects or protostars from prying optical telescopes. Collapsing due to self-gravity, the protostars form from the dense cores embedded in the molecular cloud. At the molecular cloud's estimated distance, this field of view would span over 90 light-years.

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Today's APOD is so beautiful! And it displays two regions of star formation with reflection and emission nebulas, but one appears to be large and the other one small:


The bright blue star right next to star cluster IC 348, with its faint red emission nebula, is of spectral class B1III. This means that the star, Omicron Persei, is a blue giant (but not a supergiant) star, and it is just hot enough to ionize a faint red emission nebula. If you ask me, that is why the nebula surrounding cluster IC 348 is both red and faint. In my opinion, then, it is likely that the nebula surrounding IC 348 is being ionized by Omicron Persei. That also means, of course, that I think that Omi Per and IC 348 are physically related.

This is what cluster IC 348 looks like in infrared light (or rather, in two micron light):


IC 348 looks at least reasonably respectable, doesn't it?

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. 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.

NGC 1333 is quite interesting, too.

Wikipedia wrote about NGC 1333:

The nebula region has a combined mass of approximately 450 M_☉, 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. 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. In 2011 researchers reported finding 30 to 40 brown dwarf objects in the cloud and in the Rho Ophiuchi cloud complex.

So IC 348 is older than NGC 1333, and the stars have mostly emerged from their stellar cocoons (yes, but there is still nebulosity surrounding the stars). The stars of NGC 1333 are younger than those in IC 348 and appear more tumultuous.

IC 348 looks bigger than NGC 1333 to me.

Ann

Ann wrote: ↑Thu Jan 12, 2023 11:55 am IC 348 looks bigger than NGC 1333 to me.

Ann

IC 348 is huge and intricate in IR, as you can from this unWISE image (W1 & W2 bands).

As for NGC 1333, for me it's conclusive proof that Balrogs have wings.

Knight of Clear Skies wrote: ↑Thu Jan 12, 2023 12:28 pm

Ann wrote: ↑Thu Jan 12, 2023 11:55 am IC 348 looks bigger than NGC 1333 to me.

Ann

IC 348 is huge and intricate in IR, as you can from this unWISE image (W1 & W2 bands).

Thanks, that's a great image! It demonstrates that although the nebulosity of IC 348 may be ionized from the outside (by Omicron Persei), it is being hollowed out from within.

As for NGC 1333, for me it's conclusive proof that Balrogs have wings.

Are they really related?

Maybe they are second cousins.

Ann

Stardust; It's what we're all made of! Oh! I just like this Amazing the beauties found in space!

Embedded in the link “ embedded in the molecular cloud” was the statement “…We also identify the filamentary structure of Perseus and discuss the relation between filaments and star formation, confirming that stars form preferentially in filaments…”.

That I find a curiosity of unprecedented magnitude in my mind. Though known about for the majority of my lifetime, filaments in space leading to star formation seems to have not left its mark.

Fred the Cat wrote: ↑Thu Jan 12, 2023 3:21 pm Embedded in the link “ embedded in the molecular cloud” was the statement “…We also identify the filamentary structure of Perseus and discuss the relation between filaments and star formation, confirming that stars form preferentially in filaments…”.

That I find a curiosity of unprecedented magnitude in my mind. Though known about for the majority of my lifetime, filaments in space leading to star formation seems to have not left its mark.

For me the Spider Nebula IC 417 is the best example for that topic.


https://www.sci.news/astronomy/image-sp ... 03792.html

"Along the sinuous tail in the center, and to the left, the groupings of red point sources clumped in the green are also young stars."