APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

Post a reply


This question is a means of preventing automated form submissions by spambots.
Smilies
:D :) :ssmile: :( :o :shock: :? 8-) :lol2: :x :P :oops: :cry: :evil: :roll: :wink: :!: :?: :idea: :arrow: :| :mrgreen:
View more smilies

BBCode is ON
[img] is ON
[url] is ON
Smilies are ON

Topic review
   

Expand view Topic review: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by geckzilla » Tue Jul 29, 2014 5:57 pm

Darwins wrote:Beautiful picture. Is the part I have circled in yellow the supernova?

Image
No. The progenitor is off the frame somewhere.
http://en.wikipedia.org/wiki/Cygnus_Loop
If you scroll down you can see an annotated image which denotes the approximate center. Whatever's left of the star ought to be there. It's not obvious.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Darwins » Tue Jul 29, 2014 5:05 pm

Beautiful picture. Is the part I have circled in yellow the supernova?

Image

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by retrogalax » Thu May 30, 2013 9:22 pm

I didn't think of the magnetic effect.I see the counter clockwise flexion (looking at the western and the eastern areas with the magnetic field orientation), thank you Art for the explanation.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by alter-ego » Thu May 30, 2013 5:48 am

neufer wrote:
alter-ego wrote:
I don't understand the role the B-field is that you're implying. The colored layers simply reflect the radial shock-front energy distribution where the atomic oxygen emission reveals that shell as the highest-energy, leading edge of the SN explosion, and hydrogen emission being the cooler emission following the shock wave. I'm not saying that magnetic fields don't exist in those regions, just that they are not needed to explain the emissions visible in the picture. Analogously, the higher-energy, SN1006 APOD shows the same shock-wave phenomenon but in the X-ray regime instead of the visible.
SN1006 APOD is analogous because the blue color is on the outside?

Does blue always go on the outside? [What about rainbows? http://apod.nasa.gov/apod/ap110814.html ]
Yeah, you gotta watch out for those rainbow shock fronts, they'll fool ya everytime :wink:

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Thu May 30, 2013 5:26 am

alter-ego wrote:
I don't understand the role the B-field is that you're implying. The colored layers simply reflect the radial shock-front energy distribution where the atomic oxygen emission reveals that shell as the highest-energy, leading edge of the SN explosion, and hydrogen emission being the cooler emission following the shock wave. I'm not saying that magnetic fields don't exist in those regions, just that they are not needed to explain the emissions visible in the picture. Analogously, the higher-energy, SN1006 APOD shows the same shock-wave phenomenon but in the X-ray regime instead of the visible.
SN1006 APOD is analogous because the blue color is on the outside?

Does blue always go on the outside? [What about rainbows? http://apod.nasa.gov/apod/ap110814.html ]

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by alter-ego » Thu May 30, 2013 4:25 am

neufer wrote:
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
------------------------------------------------------------------------------------
Note: Red blue glasses actually make the closer components of:
http://apod.nasa.gov/apod/ap121126.html appear to be closer :!:
I don't understand the role the B-field is that you're implying. The colored layers simply reflect the radial shock-front energy distribution where the atomic oxygen emission reveals that shell as the highest-energy, leading edge of the SN explosion, and hydrogen emission being the cooler emission following the shock wave. I'm not saying that magnetic fields don't exist in those regions, just that they are not needed to explain the emissions visible in the picture. Analogously, the higher-energy, SN1006 APOD shows the same shock-wave phenomenon but in the X-ray regime instead of the visible. I find the magnetic field discussion irrelevant and confusing to answer retrogalax's question about why the blue layer is where it is.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Beyond » Thu May 30, 2013 3:02 am

Well how about that :!: The mirror doesn't even need to be turned sideways. A straight on reflection is enough. Who wudda thought :?: It looks like even the itty-bitty things get confused by a mirror. :lol2: Hmm... people think their right and left sides get reversed, but the itty-bitty things get their up and down reversed. Sure is strange.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Thu May 30, 2013 2:23 am

Beyond wrote:
neufer wrote:
Meaning that the magnetic field
runs from the top to the bottom in: ...
Even in front of a mirror turned sideways :?: :?:

No... but parity conservation then requires
that the atomic hydrogen move clockwise.
http://www.flickr.com/photos/22611996@N02/6218610907/ wrote:
:arrow: <<This is my lino-cut portrait of Chien-Shiung Wu, her reflection (as in a mirror) and a schematic of her famous 1956 experiment which showed that unlike anything else, the weak force isn't the same if you reflect the set-up in the mirror (it isn't spatially invariant, it violates parity). She place radioactive Cobalt-60 in a strong magnetic field and showed that the emitted beta decay electrons went preferentially in one direction (shown as down towards the North pole of the electromagnet in the box on the left). When the mirror reflection of the experiment was performed, the emitted electrons go preferentially in the OPPOSITE direction (up towards the North pole of the electromagnet in the right side schematic).>>

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Beyond » Thu May 30, 2013 2:00 am

neufer wrote:Meaning that the magnetic field runs from the top to the bottom in: ...
Even in front of a mirror turned sideways :?: :?:

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Thu May 30, 2013 1:17 am

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
------------------------------------------------------------------------------------
Note: Red blue glasses actually make the closer components of:
http://apod.nasa.gov/apod/ap121126.html appear to be closer :!:

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by stephen63 » Thu May 30, 2013 12:42 am

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/

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Wed May 29, 2013 9:30 pm

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).

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by retrogalax » Wed May 29, 2013 8:29 pm

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

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Beyond » Wed May 29, 2013 8:14 pm

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

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Wed May 29, 2013 8:02 pm

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 :?:

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Beyond » Wed May 29, 2013 7:48 pm

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.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Anthony Barreiro » Wed May 29, 2013 7:20 pm

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.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Case » Wed May 29, 2013 5:36 pm

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.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Wed May 29, 2013 5:28 pm

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.

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by Case » Wed May 29, 2013 5:27 pm

Image
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:

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by AvidAmateur » Wed May 29, 2013 5:09 pm

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?

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by neufer » Wed May 29, 2013 4:45 pm

Image
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 :?: ]

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by jdjensen17 » Wed May 29, 2013 2:49 pm

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

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by stephen63 » Wed May 29, 2013 2:05 pm

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 :)

Re: APOD: NGC 6960: The Witch's Broom Nebula (2013 May 29)

by stephen63 » Wed May 29, 2013 2:00 pm

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.... :shock: :shock: :shock:

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 :wink:

Top