APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 5604
Joined: Fri Dec 04, 2009 3:27 am

APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by APOD Robot » Mon Jul 10, 2023 4:05 am

Image Stars, Dust and Nebula in NGC 6559

Explanation: When stars form, pandemonium reigns. A textbook case is the star forming region NGC 6559. Visible in the featured image are red glowing emission nebulas of hydrogen, blue reflection nebulas of dust, dark absorption nebulas of dust, and the stars that formed from them. The first massive stars formed from the dense gas will emit energetic light and winds that erode, fragment, and sculpt their birthplace. And then they explode. The resulting morass can be as beautiful as it is complex. After tens of millions of years, the dust boils away, the gas gets swept away, and all that is left is a bare open cluster of stars.

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

User avatar
Ann
4725 Å
Posts: 13867
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by Ann » Mon Jul 10, 2023 5:33 am

APOD 10 July 2023 annotated.png
Stars, Dust and Nebula in NGC 6559
Image Credit & Copyright: Adam Block, Telescope Live
Likely mechanism for creating red ridge in APOD 10 July 2023.png
Likely mechanism for creating the red ridge of NGC 6559

NGC 6559 is a young region of star formation. It is full of gas and dust. A long winding dust lane seems to connect the hot O-type star 11 Sagittarii (HD 165921) with the blue reflection nebula illuminated by newborn B-type stars. The reason why the the reflection nebula is blue is because the B-type stars are not hot enough to ionize a red emission nebula. The likely reason why the red ridge is so very red is that it is being "pushed from two directions" and ionized by clashing stellar winds. Of course the ultraviolet light from 11 Sgr also contributes strongly to the ionization of ridge.

There are some similarities between the NGC 6559 region (the subject of today's APOD) and the star forming region of Perseus and Taurus:

The California Nebula is being both "pushed" and ionized by O-type star Xi Per.

Perhaps the mechanism for creating the red ridge of NGC 6559 is slightly similar.

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

User avatar
johnnydeep
Commodore
Posts: 3257
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by johnnydeep » Mon Jul 10, 2023 2:19 pm

Just wanted to give a hearty shoutout to the OpenStax Astronomy textbook that anyone can either read for free online or download the full 1133 page PDF and read offline with an e-reader. One big benefit of all the textbooks available at OpenStax is that they are constantly being updated to reflect new information, such as the JWST images from the link about star formation provided in the APOD text.

Good stuff! - see https://openstax.org/details/books/astronomy-2e
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

zendae
Ensign
Posts: 81
Joined: Thu Sep 10, 2015 2:46 pm
Location: Harleysville, Pa

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by zendae » Mon Jul 10, 2023 3:57 pm

"...the dust boils away, the gas gets swept away..."

There are a lot of tiny motes out there getting swept and blown hither and thither. I wonder if there is a 'particle to 3D area' ratio that determines when there is and when there is not a vacuum. Or is a vacuum such an absolute that it doesn't actually exist. Between visible and dark matter, is space a vacuum anywhere? Is it only a quantum size state. Is any space that has no particle in it a tiny vacuum.

User avatar
Chris Peterson
Abominable Snowman
Posts: 18618
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by Chris Peterson » Mon Jul 10, 2023 4:10 pm

zendae wrote: Mon Jul 10, 2023 3:57 pm "...the dust boils away, the gas gets swept away..."

There are a lot of tiny motes out there getting swept and blown hither and thither. I wonder if there is a 'particle to 3D area' ratio that determines when there is and when there is not a vacuum. Or is a vacuum such an absolute that it doesn't actually exist. Between visible and dark matter, is space a vacuum anywhere? Is it only a quantum size state. Is any space that has no particle in it a tiny vacuum.
Most of the volume of space is free of any particles (other than virtual ones). A true vacuum. But the density of particles is high enough that in most of the Universe the volume of particle free areas is small- cubic millimeters or less.
Chris

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

zendae
Ensign
Posts: 81
Joined: Thu Sep 10, 2015 2:46 pm
Location: Harleysville, Pa

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by zendae » Mon Jul 10, 2023 7:04 pm

Chris Peterson wrote: Mon Jul 10, 2023 4:10 pm

Most of the volume of space is free of any particles (other than virtual ones). A true vacuum. But the density of particles is high enough that in most of the Universe the volume of particle free areas is small- cubic millimeters or less.

zendae
Ensign
Posts: 81
Joined: Thu Sep 10, 2015 2:46 pm
Location: Harleysville, Pa

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by zendae » Mon Jul 10, 2023 7:04 pm

Thanks. That makes a lot of sense.

User avatar
orin stepanek
Plutopian
Posts: 8200
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by orin stepanek » Mon Jul 10, 2023 7:49 pm

NGC6559_Block_960.jpg
The dark nebula looks somewhat like a snake :roll:
Toilet-Paper-660x371.jpg
Naughty doggy! :lol2:
You do not have the required permissions to view the files attached to this post.
Orin

Smile today; tomorrow's another day!

User avatar
VictorBorun
Captain
Posts: 1146
Joined: Fri Oct 16, 2020 10:25 pm

Re: APOD: Stars, Dust and Nebula in NGC 6559 (2023 Jul 10)

Post by VictorBorun » Tue Jul 11, 2023 5:39 am

Ann wrote: Mon Jul 10, 2023 5:33 am ImageLikely mechanism for creating the red ridge of NGC 6559
This ridge— judging by visible brightness of the likely stellar wind sources — should drift in 2 o'clock direction.

I wonder if we know some H-alpha triple peaks somewhere

Image