APOD: The Dark River to Antares (2020 May 16)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3921
Joined: Fri Dec 04, 2009 3:27 am

APOD: The Dark River to Antares (2020 May 16)

Post by APOD Robot » Sat May 16, 2020 4:05 am

Image The Dark River to Antares

Explanation: A dark river seems to flow through this sky from the horizon toward colorful clouds near red giant star Antares. Murky looking, the dark river is a dusty nebula obscuring background starlight near the central Milky Way, although the dark dust nebula contains mostly hydrogen molecular gas. Dust scattering starlight around Antares, alpha star of Scorpius, creates the unusual yellow-hued reflection nebula. Above it, bright blue double star Rho Ophiuchi is embedded in more typical dusty bluish reflection nebulae, with red emission nebulae also scattered through the interstellar space. Globular star cluster M4 looks almost like a bright star just above and right of Antares, though it lies far behind the colorful clouds, at a distance of some 7,000 light-years. The dark river itself is about 500 light years away. To create the startling night sky view, all background and foreground exposures were made back to back with the same camera and telephoto lens on the same night from the same location. In combination they produce a stunning image that reveals a range of brightness and color that your eye can't quite perceive. Recorded in the early hours of January 31, the composite also captures Mars still near the eastern horizon and rising to join rival Antares on the celestial stage. Bright Mars and its watery reflection are left of a lonely tree in the Bosque del Apache National Wildlife Refuge, New Mexico, planet Earth.

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

User avatar
orin stepanek
Plutopian
Posts: 5431
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: The Dark River to Antares (2020 May 16)

Post by orin stepanek » Sat May 16, 2020 11:59 am

Kudos to Paul on this very beautiful photo! 8-)

Reflections_APOD1200.jpg
You do not have the required permissions to view the files attached to this post.
Last edited by orin stepanek on Sat May 16, 2020 4:38 pm, edited 1 time in total.
Orin

Smile today; tomorrow's another day!

GeoXXXXX

Re: APOD: The Dark River to Antares (2020 May 16)

Post by GeoXXXXX » Sat May 16, 2020 2:41 pm

Antares in all it’s glory...
Image
It’s a big one...
Image
Rho O. In IR...
Image

Eric

User avatar
Cousin Ricky
Science Officer
Posts: 306
Joined: Mon Aug 26, 2013 4:08 pm
Location: St. Thomas, U.S. Virgin Islands (+18.3, -64.9)

Re: APOD: The Dark River to Antares (2020 May 16)

Post by Cousin Ricky » Sat May 16, 2020 3:39 pm

The sky is so clear that the stars are visible right down to the horizon!

User avatar
Chris Peterson
Abominable Snowman
Posts: 14996
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Dark River to Antares (2020 May 16)

Post by Chris Peterson » Sat May 16, 2020 4:09 pm

Cousin Ricky wrote:
Sat May 16, 2020 3:39 pm
The sky is so clear that the stars are visible right down to the horizon!
It was certainly made from a dry, dark location. But any reasonably dark location will shows stars to the horizon in a long exposure.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
AVAO
Ensign
Posts: 37
Joined: Tue May 28, 2019 12:24 pm
AKA: multiwavelength traveller
Location: Zurich

Re: APOD: The Dark River to Antares (2020 May 16)

Post by AVAO » Sat May 16, 2020 4:42 pm

ThanX GeoXXXXX

The Spotty Surface of Betelgeuse
Image

"The intriguing picture shows two, large, bright, star spots. The spots potentially represent enormous convective cells rising from below the supergiant's surface."
APOD 2010 January 6

Anatares Picture Comment:
"Using ESO’s Very Large Telescope Interferometer astronomers have constructed this remarkable image of the red supergiant star Antares. This is the most detailed image ever of this object, or any other star apart from the Sun."
Credit: ESO/K. Ohnaka

Other comment: "For the first time, they see direct signs of extremely turbulent processes inside such a giant star. It is believed that the dark spots are caused by massive eddies."

Amazing similarity?

This seems a bit strange to me...
Jac

alcor
Ensign
Posts: 32
Joined: Fri Nov 06, 2015 10:12 pm

Re: APOD: The Dark River to Antares (2020 May 16)

Post by alcor » Sat May 16, 2020 4:44 pm

The bright nebulae looks like spring flowers, on a (dark) stem, letting their seed go to wind.
Arne

De58te
Science Officer
Posts: 292
Joined: Mon Sep 30, 2013 6:35 pm

Re: APOD: The Dark River to Antares (2020 May 16)

Post by De58te » Sat May 16, 2020 11:23 pm

Nice photo. I think it is curious that the picture of red Antares kind of reminds me of the planet Mars taken with a blurry, and cheap Earth bound telescope. Even curious, if you take off the Ant prefix, you have the star named Ares which is the same name as the Greek god of war. War of course is the color of blood. And coincidence, Mars is actually the name of the Roman god of war.

User avatar
Chris Peterson
Abominable Snowman
Posts: 14996
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: The Dark River to Antares (2020 May 16)

Post by Chris Peterson » Sat May 16, 2020 11:38 pm

De58te wrote:
Sat May 16, 2020 11:23 pm
Nice photo. I think it is curious that the picture of red Antares kind of reminds me of the planet Mars taken with a blurry, and cheap Earth bound telescope. Even curious, if you take off the Ant prefix, you have the star named Ares which is the same name as the Greek god of war. War of course is the color of blood. And coincidence, Mars is actually the name of the Roman god of war.
Antares literally means the anti-Ares, the opponent of Mars (in Greek). So named because it looks very like Mars, and its position in the sky is such that Mars and it can be quite close together.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17039
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Dark River to Antares (2020 May 16)

Post by neufer » Sun May 17, 2020 12:52 am

Chris Peterson wrote:
Sat May 16, 2020 11:38 pm

Antares literally means the anti-Ares, the opponent of Mars (in Greek). So named because it looks very like Mars, and its position in the sky is such that Mars and it can be quite close together.
https://en.wikipedia.org/wiki/Antares wrote:
<<Some scholars have speculated that the star Antares may have been named after Antar, or Antarah ibn Shaddad, the Arab warrior-hero celebrated in the pre-Islamic poems Mu'allaqat.

Antarah ibn Shaddad al-Absi (AD 525–608), also known as ʿAntar, was a pre-Islamic Arab knight and poet, famous for both his poetry and his adventurous life. His chief poem forms part of the Mu'allaqāt, the collection of seven "hanging odes" legendarily said to have been suspended in the Kaaba. One of the seven clans of Bethlehem is called the Anatreh, named after ʿAntarah. It formerly acted as the guardians of the Church of the Nativity. >>
Art Neuendorffer

User avatar
MarkBour
Subtle Signal
Posts: 1022
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: The Dark River to Antares (2020 May 16)

Post by MarkBour » Sun May 17, 2020 3:54 am

GeoXXXXX wrote:
Sat May 16, 2020 2:41 pm
Antares in all it’s glory...
Image
Eric
Would it be fair to say that the larger the star, the more turbulent and irregularly shaped its photosphere? And perhaps also, the more mottled its appearance would be, were we able to resolve it?

I guess, to qualify my question, I'm wondering about models of stellar dynamics that are made by those more clever than I, and I'm asking if those models show any of these trends as correlated with size. The question may depend on the evolution of the star. For instance, when Sol becomes a red giant as predicted, it may act quite differently than a high-mass giant.
Mark Goldfain

User avatar
Ann
4725 Å
Posts: 10397
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Dark River to Antares (2020 May 16)

Post by Ann » Sun May 17, 2020 5:20 am

MarkBour wrote:
Sun May 17, 2020 3:54 am

Would it be fair to say that the larger the star, the more turbulent and irregularly shaped its photosphere? And perhaps also, the more mottled its appearance would be, were we able to resolve it?

I guess, to qualify my question, I'm wondering about models of stellar dynamics that are made by those more clever than I, and I'm asking if those models show any of these trends as correlated with size. The question may depend on the evolution of the star. For instance, when Sol becomes a red giant as predicted, it may act quite differently than a high-mass giant.
Hey, I'm chiming in as an expert of stellar evolution modelling... :wink:

Stars are not always more turbulent and irregularly shaped the larger they are. Our own Sun is fairly sizable compared with M-type dwarfs, which make up the majority of stars in our galaxy. The illustration at right shows the relative sizes of the four closest stars to the Earth, the Sun (spectral class G2V), Alpha Centauri A (G2V), Alpha Centauri B (K1V) and Proxima Centauri (M5V). As you can see, Alpha Centauri A and B are similar to the Sun in size, whereas M-type dwarf Proxima Centauri is much smaller.

Note that the Sun as well as Alpha Centauri A and B are all main sequence objects. They are still fusing hydrogen to helium in their cores and have not undergone any drastic internal changes. (As for Proxima Centauri, it may not use up its internal hydrogen for trillions of years.)

Our Sun is an extremely round object:
Phys.org wrote:

The sun is nearly the roundest object ever measured. If scaled to the size of a beach ball, it would be so round that the difference between the widest and narrow diameters would be much less than the width of a human hair.
But I really think that when it comes to red giants, they are probably more irregular the larger they are. That is my opinion, for what it is worth.

I highly recommend this page, where you can see many little VLC media player movies describing the antics of red giant stars.











The more a star has "puffed itself up to enormous proportions", the more irregular it is likely to be. Famous variable star Mira is an asymptotic giant branch star, which is to say that it has scaled the ladder to red gianthood twice, the second time becoming larger, redder, cooler and more irregular than the first, and now it is about to cast off its atmosphere and turn into a hot white dwarf surrounded by a planetary nebula. It is of course some of the cast-off material that leaves a 13 light-year-long tail of UV-glowing gas behind Mira as the star speeds through the interstellar medium.

Read about Mira here.

Ann
Color Commentator

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17039
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Dark River to Antares (2020 May 16)

Post by neufer » Sun May 17, 2020 12:07 pm

Ann wrote:
Sun May 17, 2020 5:20 am
MarkBour wrote:
Sun May 17, 2020 3:54 am

Would it be fair to say that the larger the star, the more turbulent and irregularly shaped its photosphere? And perhaps also, the more mottled its appearance would be, were we able to resolve it?

I guess, to qualify my question, I'm wondering about models of stellar dynamics that are made by those more clever than I, and I'm asking if those models show any of these trends as correlated with size. The question may depend on the evolution of the star. For instance, when Sol becomes a red giant as predicted, it may act quite differently than a high-mass giant.
Hey, I'm chiming in as an expert of stellar evolution modelling... :wink:
  • I'm very good at integral and differential calculus,
    I know the scientific names of beings animalculous;
    In short, in matters both mundane and really rather quite bazaar,
    I am the very model of a mottled Major-Giant star.
https://www.etymonline.com/search?q=mottled wrote:
mottle (n.) "a pattern or arrangement of marks or blotches of different colors or shades," 1670s, probably a back-formation from motley.

motley (adj.) late 14c., "parti-colored, variegated in color" (originally of fabric), from Anglo-French motteley, a word of unknown origin, perhaps based on Old English mot "speck" or a cognate Germanic word (see mote). But Klein's sources say probably from Gaulish. Century Dictionary rejects both. "Diversified in color," especially of a fool's dress. Hence, allusively, "a fool" (1600). As a noun meaning "cloth of contrasting mixed color" from late 14c.
https://www.etymonline.com/search?q=model wrote:
model (n.) 1570s, "likeness made to scale; architect's set of designs," from Middle French modelle (16c., Modern French modèle), from Italian modello "a model, mold," from Vulgar Latin *modellus, from Latin modulus "a small measure, standard," diminutive of modus "manner, measure". Sense of "a standard for imitation or comparison, thing or person that serves or may serve as a pattern or type" is from 1630s.
  • If the Model Boy was in either of these Sunday-schools, I did not see him. The Model Boy of my time—we never had but the one—was perfect: perfect in manners, perfect in dress, perfect in conduct, perfect in filial piety, perfect in exterior godliness; but at bottom he was a prig; and as for the contents of his skull, they could have changed place with the contents of a pie and nobody would have been the worse off for it but the pie.["Mark Twain," "Life on the Mississippi," 1883]
Meaning "motor vehicle of a particular design" is from 1900 (such as Model T, 1908; Model A, 1927; Ford's other early models included C, F, and B). Sense of "artist's model, living person who serves as the type of a figure to be painted or sculpted" is recorded by 1690s; that of "fashion model" is from 1904. German, Swedish modell, Dutch, Danish model are from French or Italian.
  • I know our mythic history, King Arthur's and Sir Caradoc's,
    I answer hard acrostics, I've a pretty taste for paradox,
    I quote in elegiacs all the crimes of Heliogabalus,
    In conics I can floor peculiarities parablous.
    I can tell undoubted Raphaels from Gerard Dows and Zoffanies,
    I know the croaking chorus from the Frogs of Aristophanes,
    Then I can hum a fugue of which I've heard the music's din afore,
    And whistle all the airs from that infernal nonsense Pinafore.
    Then I can write a washing bill in Balylonic cuneiform,
    And tell you every detail of Caractacus's uniform;
    In short, in matters both mundane and really rather quite bazaar,
    I am the very model of a mottled Major-Giant star.
Art Neuendorffer

User avatar
MarkBour
Subtle Signal
Posts: 1022
Joined: Mon Aug 26, 2013 2:44 pm
Location: Illinois, USA

Re: APOD: The Dark River to Antares (2020 May 16)

Post by MarkBour » Mon May 18, 2020 6:41 am

Thank you for the novel rhymes, Art,
and thank you for the expert opinion, Ann.
I did indeed very much enjoy viewing the simulations made by Bernd Freytag.
Mark Goldfain

User avatar
Ann
4725 Å
Posts: 10397
Joined: Sat May 29, 2010 5:33 am

Re: APOD: The Dark River to Antares (2020 May 16)

Post by Ann » Mon May 18, 2020 7:44 am

MarkBour wrote:
Mon May 18, 2020 6:41 am
Thank you for the novel rhymes, Art,
and thank you for the expert opinion, Ann.
I did indeed very much enjoy viewing the simulations made by Bernd Freytag.
Thank you, Mark! :D

And thank you too, Art. I really enjoyed your poem - slightly altered, I'm sure - and I particularly enjoyed this part of it:

Then I can write a washing bill in Balylonic cuneiform,
And tell you every detail of Caractacus's uniform;
In short, in matters both mundane and really rather quite bazaar,
I am the very model of a mottled Major-Giant star.


:lol2:

Anyway, I have to add something because one of my links is broken. So here again you can see what a 1 M star does during its asymptotic giant branch phase : It becomes brighter, redder and cooler, and it certainly becomes more irregular.

Ann
Color Commentator

User avatar
neufer
Vacationer at Tralfamadore
Posts: 17039
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: The Dark River to Antares (2020 May 16)

Post by neufer » Mon May 18, 2020 3:18 pm

Click to play embedded YouTube video.
Ann wrote:
Then I can write a washing bill in Balylonic cuneiform,

And tell you every detail of Caractacus's uniform;

In short, in matters both mundane and really rather quite bazaar,

I am the very model of a mottled Major-Giant star.
Note: Caratacus's uniform consisted
of your Class A loin cloth. :arrow:
Art Neuendorffer