APOD: The Dark Seahorse in Cepheus (2021 Nov 05)

[APOD Robot]

The Dark Seahorse in Cepheus

Explanation: Light-years across, this suggestive shape known as the Seahorse Nebula appears in silhouette against a rich, luminous background of stars. Seen toward the royal northern constellation of Cepheus, the dusty, obscuring clouds are part of a Milky Way molecular cloud some 1,200 light-years distant. It is also listed as Barnard 150 (B150), one of 182 dark markings of the sky cataloged in the early 20th century by astronomer E. E. Barnard. Packs of low mass stars are forming within, but their collapsing cores are only visible at long infrared wavelengths. Still, the colorful stars of Cepheus add to this pretty, galactic skyscape.

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[Ann]

I apologize for not posting a version of today's APOD, because it is too large (~700 KB), and I am only allowed to post three attachments here.

Yes, but look at this wide field image of Barnard 150 (the Seahorse) set in perspective...

The Dark Seahorse and friends in Cepheus. Photo: José Jiménez.

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It looks amazing, isn't it? The Dark Seahorse is dead center, looking like a man running with one short and one extremely long leg, or perhaps like a dancing or stumbling man trailing a very long tail behind him. (Can't see the Seahorse, sorry.)

At far left is bright spiral galaxy NGC 6946 - surely you can find it. To the lower left of it is cluster NGC 6939. You can see both objects together here. At right is the red emission nebula Sharpless 2–129, also known as the Flying Bat Nebula , and inside it is the elongated blue nebula known as Ou4, or the Giant Squid Nebula . Talk about an impressive neighborhood for the Dark Seahorse, right?

Anyway. The Dark Seahorse is an elongated dust lane, a concentration of gas and dust, and these things are so often elongated. A variation of the dark dust lane is the Bok Globule, which is an "island" of gas and dust inside an emission nebula, where it is being pummeled by stellar winds and harsh ultraviolet radiation, so that it - the Bok Globule - is being evaporated. This is my favorite Bok Globule:

Finger of God and man hanging on Carina Nebula.png

Finger of God (or possibly a ruder finger)
in the Carina Nebula. Photo: Hubble.

Finger of God and man hanging on annotated.png

Finger of God and a man hanging on to it.

Let's return to the more "normal elongated dust lanes. An interesting one is known as the Snake Nebula in Sagittarius (not to be confused with this guy in Ophiuchus):

Two infrared views of the Snake Nebula by the Spitzer and Herschel telescopes. Massive stars are forming in the locations called P1 and P6.

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Note that the long Snake Nebula is only forming stars in a very few places. That is what star formation is like, as far as I can understand: It takes a concentration of gas and dust to form stars, which means that stars form where there is dust (and gas), but dust lanes are "barren" in most places.

To see what that means, take a look at this pair of galaxies:

Interacting galaxies AM 1316-241, consisting of a foreground spiral galaxy and a background elliptical. The light from the elliptical reveals the nature of the dust lane of the spiral. NASA, ESA, the Hubble Heritage (STScI/AURA)-ESA/Hubble Collaboration, and W. Keel .

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A very long, curving outer dust lane in the spiral galaxy is seen in silhouette against the background light of the elliptical galaxy. A few blue spots in the dark dust reveals sites of star formation. But as you can see, most of the dark dust is "barren".

Does the Dark Seahorse of Cepheus carry any roe in its depths? Who knows?

Tiny seahorse.png

Ann

[orin stepanek]

b150_avitabile1092c.jpg

I drew a circle to show my thoughts of dark seahorse
nebula!

Seahorse-Australia.jpg

Borrowed from XgeoX post in the horse head nebula post for
comparison of dark cloud nebula with seahorse!

[neufer]

Winged hippocamp in a fountain, Kansas City, Missouri, (1937)

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<<The hippocampus or hippocamp, also hippokampos (plural: hippocampi or hippocamps; Ancient Greek: ἱππόκαμπος, from ἵππος, "horse" and κάμπος, "sea monster"), often called a sea-horse in English,is a mythological creature shared by Phoenician, Etruscan, Pictish, Roman and Greek mythology, though its name has a Greek origin. The hippocampus is typically depicted as having the upper body of a horse with the lower body of a fish. Coins minted at Tyre around the 4th century BC show the patron god Melqart riding on a winged hippocampus and accompanied by dolphins.

King Cepheus is prominently featured in the Perseus legend as the husband of Cassiopeia and father of Princess Andromeda. Various sources described his kingdom to be the city of Joppa (Jaffa) in Phoenicia, which was named after the elder Cepheus' wife, Iope. The term Phoenicia is an ancient Greek exonym that most likely described one of their most famous exports, a dye also known as Tyrian purple; it did not correspond precisely to a cohesive culture or society as it would have been understood natively.>>

[johnnydeep]

The Seahorse Nebula demystified:

seahorse nebula.JPG

[Guy]

This site is kinda epic!

[neufer]

This site is kinda epic!

The ten main characteristics of an epic:

• Begins in medias res (“in the thick of things”).
  The setting is vast, covering many nations, the world or the universe.
  Begins with an invocation to amuse a muse (epic invocation).
  Begins with a statement of the theme.
  Includes the use of epithets.
  Contains long lists, called an epic catalogue.
  Features long and formal speeches.
  Shows divine intervention in human affairs.
  Features heroes that embody the values of the civilization.
  Often features the tragic hero's descent into the underworld or hell.

The hero generally participates in a cyclical journey or quest, faces adversaries (e.g., Ann, Bystander, Chris ...) that try to defeat him in his journey and returns home significantly transformed by his journey.

[starsurfer]

Doesn't the Barnard catalogue include 349 entries? The first part published in 1919 did have only 182 entries but then the second part was published in 1927.

[neufer]

Click to play embedded YouTube video.

[johnnydeep]

Click to play embedded YouTube video.

Some people have far too much CPU time on their hands.

[neufer]

Some people have far too much CPU time on their hands.

Structure of protein Carboxypeptidase U (CPU)

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<<Carboxypeptidase U (CPU) is an enzyme that, in humans, is encoded by the gene CPB2. CPU is synthesized by the liver and circulates in the plasma as a plasminogen-bound zymogen. When it is activated by proteolysis at residue Arg92 by the thrombin/thrombomodulin complex, CPU exhibits carboxypeptidase activity. Activated CPU reduces fibrinolysis by removing the fibrin C-terminal residues that are important for the binding and activation of plasminogen. Carboxypeptidases are enzymes that hydrolyze C-terminal peptide bonds. The carboxypeptidase family includes metallo-, serine, and cysteine carboxypeptidases. According to their substrate specificity, these enzymes are referred to as carboxypeptidase A (cleaving aliphatic residues) or carboxypeptidase B (cleaving basic amino residues). The protein encoded by this gene is activated by thrombin and acts on carboxypeptidase B substrates. After thrombin activation, the mature protein downregulates fibrinolysis.>>

[johnnydeep]

Some people have far too much CPU time on their hands.

Structure of protein Carboxypeptidase U (CPU)

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<<Carboxypeptidase U (CPU) is an enzyme that, in humans, is encoded by the gene CPB2. CPU is synthesized by the liver and circulates in the plasma as a plasminogen-bound zymogen. When it is activated by proteolysis at residue Arg92 by the thrombin/thrombomodulin complex, CPU exhibits carboxypeptidase activity. Activated CPU reduces fibrinolysis by removing the fibrin C-terminal residues that are important for the binding and activation of plasminogen. Carboxypeptidases are enzymes that hydrolyze C-terminal peptide bonds. The carboxypeptidase family includes metallo-, serine, and cysteine carboxypeptidases. According to their substrate specificity, these enzymes are referred to as carboxypeptidase A (cleaving aliphatic residues) or carboxypeptidase B (cleaving basic amino residues). The protein encoded by this gene is activated by thrombin and acts on carboxypeptidase B substrates. After thrombin activation, the mature protein downregulates fibrinolysis.>>

And some posters see very interesting, yet sometimes not very relevant, tangents Not complaining though...