Starship Asterisk*

The Red Spider Planetary Nebula

Explanation: Oh what a tangled web a planetary nebula can weave. The Red Spider Planetary Nebula shows the complex structure that can result when a normal star ejects its outer gases and becomes a white dwarf star. Officially tagged NGC 6537, this two-lobed symmetric planetary nebula houses one of the hottest white dwarfs ever observed, probably as part of a binary star system. Internal winds emanating from the central stars, visible in the center, have been measured in excess of 1000 kilometers per second. These winds expand the nebula, flow along the nebula's walls, and cause waves of hot gas and dust to collide. Atoms caught in these colliding shocks radiate light shown in the above representative-color picture by the Hubble Space Telescope. The Red Spider Nebula lies toward the constellation of the Archer (Sagittarius). Its distance is not well known but has been estimated by some to be about 4,000 light-years.

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Reminds me of the "X red Square nebula"...

and the larger image reminds me of the "Running Man Nebula"...

Why is there a dark patch in the center...is that a relative void or something???

:---[===] *

If the central star of this nebula is one of the hottest known, then it is interesting that the nebula is so red. I would have expected more blue-green OIII emission in the presence of such a very hot star.

Ann

You are looking at an hourglass figure at an angle. These things always do that.

Awesome but so frustrating! I'd love to be able to rotate a view of this nebula in 3-D so the complete shape could be seen.

What is a 1000 meters a second mean in laimans term. ( = to ? miles an hour).

royalpalms6@msn.com wrote:What is a 1000 meters a second mean in laimans term. ( = to ? miles an hour).

Your browser probably has a small search field in the top area, with a drop-down for selecting which search engine to use. Select Google. (Others will also work, I'm sure, but I used Google.) Enter this into that search field (or in Google's home page search field if you wish)...

"convert 1000 meters a second to mph"

The answer is in the search results: 2236.94 mph.

You can use the same technique to calculate any reasonable -- and some unreasonable -- conversions.

Rob

rstevenson wrote:

royalpalms6@msn.com wrote:
What is a 1000 meters a second mean in laimans term. ( = to ? miles an hour).

Your browser probably has a small search field in the top area, with a drop-down for selecting which search engine to use. Select Google. (Others will also work, I'm sure, but I used Google.) Enter this into that search field (or in Google's home page search field if you wish)...

"convert 1000 meters a second to mph"

The answer is in the search results: 2236.94 mph.

And don't forget we are talking 1000 kilometers per second here.

Ann wrote:
If the central star of this nebula is one of the hottest known, then it is interesting that the nebula is so red. I would have expected more blue-green OIII emission in the presence of such a very hot star.

Most of the oxygen is probably much more highly ionized than just doubly ionized .

And you are assuming that any doubly ionized oxygen there would last for a long enough period of time for a forbidden blue-green OIII photon to be emitted before being knocked about by an ultraviolet photon from the white dwarf.

Most of the hydrogen is fully ionized but an isolated proton & electron at least have the time to connect up and rapidly radiate non-forbidden Lyman & Balmer photons before an ultraviolet photon from the white dwarf comes along to re-ionize it.

Oh, I should have mentioned this earlier; my apologies. This APOD is mirrored here as well as on the other APOD mirrors.

Goddard's servers were shut down earlier today as a precaution against a power outage due to Hurricane Sandy.

emanating from the central stars, visible in the center

I don't see any stars. Only a weird whiteish thing with a black centre.

500pesos wrote:

emanating from the central stars, visible in the center

I don't see any stars. Only a weird whiteish thing with a black centre.

http://pintester.com/2012/08/honey-and- ... d-removal/

http://asterisk.apod.com/viewtopic.php?f=23&t=30183