Starship Asterisk*

NGC 6960: The Witch's Broom Nebula

Explanation: Ten thousand years ago, before the dawn of recorded human history, a new light would have suddenly have appeared in the night sky and faded after a few weeks. Today we know this light was from a supernova, or exploding star, and record the expanding debris cloud as the Veil Nebula, a supernova remnant. This sharp telescopic view is centered on a western segment of the Veil Nebula cataloged as NGC 6960 but less formally known as the Witch's Broom Nebula. Blasted out in the cataclysmic explosion, the interstellar shock wave plows through space sweeping up and exciting interstellar material. Imaged with narrow band filters, the glowing filaments are like long ripples in a sheet seen almost edge on, remarkably well separated into atomic hydrogen (red) and oxygen (blue-green) gas. The complete supernova remnant lies about 1400 light-years away towards the constellation Cygnus. This Witch's Broom actually spans about 35 light-years. The bright star in the frame is 52 Cygni, visible with the unaided eye from a dark location but unrelated to the ancient supernova remnant.

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Not an expert here, but I noticed a huge lens arc in the top right corner. Is this from NGC 6960 or from something else? None of my internet searches came up with any mention of a lens arc in this galaxy.

Thanks!

NotAScientist wrote:Not an expert here, but I noticed a huge lens arc in the top right corner. Is this from NGC 6960 or from something else? None of my internet searches came up with any mention of a lens arc in this galaxy.

Thanks!

Good question. However, NGC 6960 is not a galaxy. A galaxy is a huge conglomerate of stars, and large galaxies can be extremely massive.

NGC 6960 is a supernova remnant and not particularly massive at all. What we see is gas that was blasted off the progenitor star when it exploded, and this gas is still speeding though space. The speeding gas from the supernova is colliding with the "interstellar medium", which is an extremely, extremely thin "gas" spread throughout the Milky Way. The collision between these two very different "gases" is what causes the glow. The arc in the upper right corner is not a lens, but simply an elegantly curved "collision front" which glows red from the energy of the collision.

Ann

I bet the terms "narrow band" and "wide (or broad?) band" have been defined in previous APOD postings, but I'm curious about what these mean--the term "narrow band" being used in this description. I presume it's something like the range of wavelengths to which a CCD or other telescopic collector is "tuned" to capture...or something. Perhaps including a hyperlink--which is so often, and very helpfully, done with postings would be good here--though I understand that after hyperlinking a term 50 times you might assume readers would know it by now! Please know how terrific this site is, and how much I, for one, appreciate all of the work that goes into it. Extraordinary!

Awesome Close Up....

R.I.P.....little Star.....

:---[===]*

sbraun wrote:I bet the terms "narrow band" and "wide (or broad?) band" have been defined in previous APOD postings, but I'm curious about what these mean--the term "narrow band" being used in this description. I presume it's something like the range of wavelengths to which a CCD or other telescopic collector is "tuned" to capture...or something. Perhaps including a hyperlink--which is so often, and very helpfully, done with postings would be good here--though I understand that after hyperlinking a term 50 times you might assume readers would know it by now! Please know how terrific this site is, and how much I, for one, appreciate all of the work that goes into it. Extraordinary!

Here is a simple explanation...and as you go down the page, you will see why I have not gotten into filters....

The bottom link is to the combined color picture of the filters on M27, one of my favorite objects. It is interesting to note the X pattern in the nebula...I had not noticed that before. Filters can show so much more details to an object.

http://www.astrodon.com/products/filters/narrowband/

http://www.astrodonimaging.com/gallery/ ... ?imgID=148

:---[===] *

To Ann et al:
Followed a couple of the links, but have not seen any discussion of possibly having identified the central remnant of the supernova. Has anyone done that? Thanks!

http://apod.nasa.gov/apod/ap121126.html - what? no central remnant??
https://en.wikipedia.org/wiki/File:Cygn ... abeled.png - the '+' marks the center. Whatever was there in 10,000BC is no longer.

Boomer12k wrote:

sbraun wrote:I bet the terms "narrow band" and "wide (or broad?) band" have been defined in previous APOD postings, but I'm curious about what these mean--the term "narrow band" being used in this description. I presume it's something like the range of wavelengths to which a CCD or other telescopic collector is "tuned" to capture...or something. Perhaps including a hyperlink--which is so often, and very helpfully, done with postings would be good here--though I understand that after hyperlinking a term 50 times you might assume readers would know it by now! Please know how terrific this site is, and how much I, for one, appreciate all of the work that goes into it. Extraordinary!

Here is a simple explanation...and as you go down the page, you will see why I have not gotten into filters....

The bottom link is to the combined color picture of the filters on M27, one of my favorite objects. It is interesting to note the X pattern in the nebula...I had not noticed that before. Filters can show so much more details to an object.

http://www.astrodon.com/products/filters/narrowband/

http://www.astrodonimaging.com/gallery/ ... ?imgID=148

:---[===] *

Good link, Boomer. That pretty much explains it. They can get quite expensive, for sure.
I saw this image posted on his site and wondered when it would show up here

I'm guessing that IF there is no central remnant, then it is a Type 1a supernova. Of course, from what I've discovered here, it's never that simple

Why isn't the Western Veil on the left? Is it labeled from the perspective of where the star used to be?

jdjensen17 wrote:
Why isn't the Western Veil on the left?

Is it labeled from the perspective of where the star used to be?

The Western Veil is on the right (with North up) because we look up at the sky but down on the Earth such that East & West are reversed (; i.e., the sky is a mirror image of the Earth.)

The Western Veil would, however, be on the left (with South up) in the Southern Hemisphere since North & South are then reversed.

[Quiz question:

Why do mirrors switch left & right but not up & down ]

Why would light from a source 1400 light years away require 10,000 years to travel to earth visibility? Should it not require 1400 years?

neufer wrote:

jdjensen17 wrote:Why isn't the Western Veil on the left?

The Western Veil is on the right (with North up) because we look up at the sky but down on the Earth such that East & West are reversed.

Maybe my little drawing will help illustrate this mirroring of the directions:

AvidAmateur wrote:
Why would light from a source 1400 light years away require 10,000 years to travel to earth visibility?

Should it not require 1400 years?

Light from a source both 1400 light years away & 11,400 years ago
took 1400 light years to be observed on Earth 10,000 years ago.

AvidAmateur wrote:Why would light from a source 1400 light years away require 10,000 years to travel to earth visibility? Should it not require 1400 years?

The light that we see today started traveling towards us 1400 years ago: We see the nebula as it was 1400 years ago.
10,000 years ago there was no nebula, but a super bright exploding star. Since then, the remnant started fading and expanding, over thousands of years, into what we see today.

This is an awesome picture. I love imagining our distant ancestors being amazed by a brilliant new star in the sky. Who knows what stories and traditions they may have handed down to their descendants?

The Veil nebula is also a beautiful object through a large telescope under a dark sky, especially with an Oxygen-III filter that brings out the features that appear blue in Martin Pugh's photo here. Through a telescope our eyes don't perceive the kind of technicolor reds and blues you see in a long-exposure photo, but it does look faintly greenish. There's something magical about seeing it for yourself in real time and being able to zoom in and out and pan around to see different parts of the nebula.

neufer wrote:Why do mirrors switch left & right but not up & down

Mirrors don't switch anything. They merely reflect what is in front of them.

Beyond wrote:

neufer wrote:
Why do mirrors switch left & right but not up & down

Mirrors don't switch anything. They merely reflect what is in front of them.

Then why does your right hand become a left hand

It doesn't. Both hands are reflected in the part of the mirror that they are in front of.

Are the two layers in the veil caused by the different atomic masses of the molecules ? Why the blue layer is above ?

retrogalax wrote:
Are the two layers in the veil caused by
the different atomic masses of the molecules ?

• Yes.

retrogalax wrote:
Why the blue layer is above ?

For the same reason the blue layer is below the red layer
on the East side of the supernova remnant:
http://apod.nasa.gov/apod/ap121126.html

Doubly ionized oxygen (blue-green) has 8 times the
the mass-to-charge ratio (m/Q) of atomic hydrogen (red)
and thus will be much less affected by magnetic fields.

As the different plasmas passed through:

• 1) the remnant dipole field of the exploded star
  2) and/or the residual galactic magnetic field

the atomic hydrogen (red) curved in a counter-clockwise direction more than the doubly ionized oxygen
(about a northerly directed axis).

neufer wrote:
As the different plasmas passed through:

• 1) the remnant dipole field of the exploded star
  2) and/or the residual galactic magnetic field

the atomic hydrogen (red) curved in a counter-clockwise direction more than the doubly ionized oxygen
(about a northerly directed axis).

For us dummies(specifically me), does that follow the right hand rule?
http://www.magnet.fsu.edu/education/tut ... handrules/

stephen63 wrote:

neufer wrote:
As the different plasmas passed through:

• 1) the remnant dipole field of the exploded star
  2) and/or the residual galactic magnetic field

the atomic hydrogen (red) curved in a counter-clockwise direction more than the doubly ionized oxygen
(about a northerly directed axis).

For us dummies(specifically me),
does that follow the right hand rule?
http://www.magnet.fsu.edu/education/tut ... handrules/

• For all of us, actually.

Meaning that the magnetic field runs from the top to the bottom in: http://apod.nasa.gov/apod/ap121126.html

neufer wrote:Meaning that the magnetic field runs from the top to the bottom in: ...

Even in front of a mirror turned sideways