Well, wow! Today's APOD is so large that all my three attachments will be used up in a jiffy!
Okay, here's the first one...
The Pencil Nebula Supernova Shock Wave.
Image Credit & Copyright: Helge BΓΌsing
I like the caption:
This supernova shock wave plows through interstellar space at over 500,000 kilometers per hour. Centered and moving upward in the sharply detailed color composite its thin, bright, braided filaments are actually long ripples in a cosmic sheet of glowing gas seen almost edge-on.
...
Nearly 5 light-years long it represents only a small part of the Vela supernova remnant though.
Okay, so where in the Vela supernova remnant is the Pencil Nebula located?
Supernova remnants always contain at least some (blue-green) OIII emission. I'd say that Marco Lorenzi has used a lot of OIII to make the Vela supernova remnant look extra blue-green and set it apart from the red hydrogen alpha background.
Note the Pencil Nebula in Marco Lorenzi's image! It is at far left, at 9 o'clock.
Okay, but if we have a supernova remnant, then we may have some sort of compact body that was left behind after the explosion. And we do - it's the Vela pulsar! Time for my second attachment!
The Vela pulsar in the Vela supernova remnant. Note the
Pencil Nebula at lower left. Credit: Optical: DSS/Davide De Martin
X-ray: NASA/CXC/Univ of Toronto/M.Durant et al.
The Vela pulsar is one of the most important sources of X-rays in the Milky Way.
I found this video of the Vela Pulsar on Youtube:
Click to play embedded YouTube video.
And let's take a moment to consider the colors of the Pencil Nebula, and the optical colors of all of the Vela supernova remnant. The colors are blue-green and red.
The blue-green gaseous filaments of the Vela supernova remnant are the outermost ones, the ones that crash into the interstellar medium and make it glow green from OIII. Behind the green OIII, the nebulosity is red from hydrogen alpha.
OIII represents a considerably higher degree of ionization than HΞ±. Green represents the impact itself, and red is the debris that follows after.
Ann
Well, wow! Today's APOD is so large that all my three attachments will be used up in a jiffy!
Okay, here's the first one...
[float=left][attachment=1]NGC2736_Helge_Buesing1024[1].jpg[/attachment][c][size=85][color=#0040FF]The Pencil Nebula Supernova Shock Wave.
Image Credit & Copyright: Helge BΓΌsing[/color][/size][/c][/float]
[clear][/clear]
I like the caption:
[quote]This supernova shock wave plows through interstellar space at over 500,000 kilometers per hour. Centered and moving upward in the sharply detailed color composite its thin, bright, braided filaments are actually long ripples in a cosmic sheet of glowing gas seen almost edge-on.
...
Nearly 5 light-years long it represents only a small part of the Vela supernova remnant though.[/quote]
Okay, so where in the Vela supernova remnant is the Pencil Nebula located?
[img3="Vela Supernova Remnant. Note the Pencil Nebula at far left.
Credit & Copyright: Marco Lorenzi (Star Echoes)"]https://apod.nasa.gov/apod/image/1009/vela_lorenzi_c0.jpg[/img3]
Supernova remnants always contain at least some (blue-green) OIII emission. I'd say that Marco Lorenzi has used a lot of OIII to make the Vela supernova remnant look extra blue-green and set it apart from the red hydrogen alpha background.
[b][color=#008080]Note the Pencil Nebula in Marco Lorenzi's image![/color][/b] It is at far left, at 9 o'clock.
Okay, but if we have a supernova remnant, then we may have some sort of compact body that was left behind after the explosion. And we do - it's the Vela pulsar! Time for my second attachment!
[float=left][attachment=0]vela_optical_xray[1].jpg[/attachment][c][size=85][color=#0040FF]The Vela pulsar in the Vela supernova remnant. Note the
Pencil Nebula at lower left. Credit: Optical: DSS/Davide De Martin
X-ray: NASA/CXC/Univ of Toronto/M.Durant et al. [/color][/size][/c][/float]
[clear][/clear]
The Vela pulsar is one of the most important sources of X-rays in the Milky Way.
[img3="Milky Way in X-rays. Note the Vela pulsar (actually the Vela supernova remnant), the big yellowish blob at right. Credit: SRG/eROSITA"]https://i0.wp.com/math.ucr.edu/home/baez/astronomical/eROSITA_x-ray_map_1.jpg[/img3]
I found this video of the Vela Pulsar on Youtube:
[youtube]https://www.youtube.com/watch?v=fmN0CEH9Exg[/youtube]
And let's take a moment to consider the colors of the Pencil Nebula, and the optical colors of all of the Vela supernova remnant. The colors are blue-green and red.
[img3="Vela supernova remnant. Credit: Harel Boren. The outermost gaseous filaments are green from doubly ionized oxygen, OIII. "]https://upload.wikimedia.org/wikipedia/commons/thumb/2/2d/Vela_Supernova_Remnant_by_Harel_Boren_%28155256626%29_%28cropped%29.jpg/513px-Vela_Supernova_Remnant_by_Harel_Boren_%28155256626%29_%28cropped%29.jpg[/img3]
The blue-green gaseous filaments of the Vela supernova remnant are the outermost ones, the ones that crash into the interstellar medium and make it glow green from OIII. Behind the green OIII, the nebulosity is red from hydrogen alpha.
OIII represents a considerably higher degree of ionization than HΞ±. Green represents the impact itself, and red is the debris that follows after.
Ann