803 replies to this topic

[AllanDystrup]

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Cepheus OB & EN

     

     The view in late autumn from the solar system, out through the outer part of our Local Ori-Cyg arm, past the interarm-gap and towards and through the outer Perseus arm in the direction of Cassiopeia - Cepheus...
     WOW!, is that just filled with star clusters and nebulae, including associations of young and massive type-O and -B hot giant stars ionizing the surrounding molecular clouds, creating beautiful embroideries of emission fronts and dark pillars and globules.

 

     There are more objects in this area than I can / care to upload here to CN in the form of individual obs. reports, but I'll share some appetizers here, and then provide a link to a PDF with more background info and a collection af my reports from the area.

 

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     -- Allan

[AllanDystrup]

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CEP OB2a

     

  

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[AllanDystrup]

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[j.gardavsky]

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CEP OB2a 02.png

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Hello Allan,

 

and thank you very much for these amazing infos!

 

In the above picture, is the Cepheus Bubble the C2140+658 ?

See also IDSA p.8

 

Best regards,

JG

[AllanDystrup]

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Hi JD, -- and thank you back 

 

Yes, I'm pretty sure that C2140+658 -- as depicted in IDSA p.8 -- must be Stoyan & Schurig's attempt at schematically outlining the Cepheus Bubble;

Personally I'd rather draw the outline a bit more like this (below), based on this research: https://ui.adsabs.ha.....241P/abstract (download PDF), quote (Fig. 3):

 

"Sharpless H II regions and the CepOB2 association. The locations of the H II regions from the Sharpless catalog are indicated by circles, which have radii representing the approximate angular extent of the H II region. Except IC 1396 (S131), the H II regions do not have circular morphologies. The larger star symbols indicate O-type stars and smaller star symbols indicate stars of spectral types B0-B2"

 

 

     The IDSA is not so comprehensive with regard to emission nebulae (Sharpless) -- for instance it does not mark SH-2 140, 145, 150 and Sh-2 137, Sh2-139 etc., so for this purpose I rely more on sources like Bracken's "The Astrophotography Atlas" (though I observe visually, sort of ...)

 

     -- Allan

Edited by AllanDystrup, 18 October 2024 - 06:16 AM.

[j.gardavsky]

Hello Allan,

 

and thank you very much for the update.

 

On the eastern circumference, thare are two SNR relicts:

The G106.3+2.7 (Sh2-141 The Boomerang Nebula, first found by Gaze&Shajn [GS-55] 256, visible through the H-beta 5.5nm),

and the G108.2-0.6 shell.

 

Any other SNR relicts, belonging to the Cepheus bubble, as known?

 

Best regards,

JG

[AllanDystrup]

JG:
 

Any other SNR relicts, belonging to the Cepheus bubble, as known?

 

     The Cepheus Bubble (CB) itself is a now 10dg Ø expanding shell, created by several SNe in the 1.Gen OB-cluster at the position that is now occupied by the 2.Gen OC N7160. The closest we can come to a SNR from this event is the sphere of CO-emission and collapsing H-II regions observable as SH-2 nebulae today.
 

     Similarly the Cepheus Flare forms part of another big but older expanding shell of interstellar matter that encloses a supernova remnant void inside the Flare.
 

     Some massive 2.Gen stars at the periphery of the CB have recently gone supernova and left puffs of SNR, most being small and some mostly observable in the radio spectrum. I have not (yet) tried to hunt down these, though it could be interesting as a separate project.

 

Cep OB2B

 

Talking about the CB, I'll include this page of my obs. log (below), that also includes a ref. to a recent (2023) study of the history of star formation in the region of CEP OB2 + periphery

 

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     -- Allan

[AllanDystrup]

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[AllanDystrup]

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[AllanDystrup]

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Cep OB6

     

     

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[AllanDystrup]

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[AllanDystrup]

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[AllanDystrup]

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Cep OB1

     

     

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[AllanDystrup]

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     There's another concentration of hot OB-stars in Cepheus OB1, around 1dg SE of Epsilon Cep; This includes the evolved massive ultra-hot Wolf-Rayet stars: WR153ab and WR 152, which are ionizing the surrounding HI-cloud, creating the Dragon/Lion emission nebula (Sharpless 132).

 

     In this observation I focused on the stars of Cep OB1, and only caught the central, most luminous, part of Sh2-132, mostly because the observation conditions were rather bad: low transparency (~3/7) with 'soft' views due to banks of high, drifting fog. Besides the WR-stars, the Cep OB1 association also features the RW Cephei early K-type red/yellow luminous hypergiant, close to the small Be94 OC. RW is a semi-regular variable star similar to other cool massive stars like Betelgeuse and VY CMa that have undergone one or more dimming events.

 

 

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     -- Allan

[AllanDystrup]

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Cep OB3

     

     Cep OB3 is a stellar association in our Local Ori-Cyg spiral arm, close to the solar system. It is embedded in a cloud of interstellar dust and gas, showing sequential star formation propagating from a supernova explosion in the older (8 Myr) and less concentrated north-eastern subgroup: A, to the very young (5.5 Myr) and dense western subgroup: B.     

 

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[AllanDystrup]

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[AllanDystrup]

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Cep OB4

     

     

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[AllanDystrup]

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[AllanDystrup]

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Cas OB5

     

     

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[AllanDystrup]

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[AllanDystrup]

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The Owl (and Dolphin), the Pacman and the Rose...

     

     

     Below the Cassiopeia Arc of OB-associations in the Perseus Spiral Arm of the galactic disc are found some older open clusters with blue straggler stars (Owl, Rose), but also the 3.5 Myr young IC1590 in Pacman with the hot  type O6-trapezium system (HD 5005) at the core.

     Here's first the 21Myr old Owl OC with a pair of supergiant stars: φ1 - φ2 :

 

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     -- Allan

 

 

[AllanDystrup]

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Pacman

     

     

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[AllanDystrup]

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Caroline's Rose

     

     

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[AllanDystrup]

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[AllanDystrup]

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Summary 

Fall observation reports for Cepheus and Cassiopeia

     

     

     Let me wrap up these last posting of my obs. reports from my travels to the OB-associations and nebulae in the Cepheus and Cassiopeia regions of the autumn Milky Way; I'll do that by posting links to the uploaded PDF's covering these observations:

 

• OB-Associations in CEP & CAS: https://qualitycode....bs1-cep-cas.pdf

• Nebulae in CEP & CAS: https://qualitycode....bs1-cep-cas.pdf

 

     On the same site, you can find more observations/information on some of the more interesting NGC's in CEP:

https://qualitycode....icngc-s-cep.pdf

https://qualitycode....ngc-f-cep-2.pdf

 

     I'm in the process of 'bundeling' and uploading my obs. reports to this site: https://qualitycode....tion-log-pages/, but I still have a big pile in my out-box to post up there.

     So for now, I want thank those of you here at CN who have viewed (quite a few views in fact, -- more than 150.000 and counting), followed and even liked the post in this Rich Field thread. -- That makes it worth for me to continue sharing  

 

Thank you!

     -- Allan

Edited by AllanDystrup, 08 November 2024 - 10:42 AM.