APOD: M57: The Ring Nebula (2012 Apr 20)

[APOD Robot]

M57: The Ring Nebula

Explanation: Except for the rings of Saturn, the Ring Nebula (M57) is probably the most famous celestial band. Its classic appearance is understood to be due to perspective - our view from planet Earth looks down the center of a roughly barrel-shaped cloud of glowing gas. But expansive looping structures are seen to extend far beyond the Ring Nebula's familiar central regions in this intriguing composite of ground based and Hubble Space Telescope images with narrowband image data from Subaru. Of course, in this well-studied example of a planetary nebula, the glowing material does not come from planets. Instead, the gaseous shroud represents outer layers expelled from the dying, once sun-like star at the nebula's center. Intense ultraviolet light from the hot central star ionizes atoms in the gas. Ionized oxygen atoms produce the characteristic greenish glow and ionized hydrogen the prominent red emission. The central ring of the Ring Nebula is about one light-year across and 2,000 light-years away. To accompany tonight's shooting stars it shines in the northen constellation Lyra.

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[Mactavish]

Another image typical of Gendler's work. Brilliant!

[avdhoeven]

I like the contents of the image but in my opinion the processing is way overdone. I think much more detail in a softer way can be shown. But that's a personal opinion.

[rgendler]

People who are familiar with M57 will understand that the attempt here was "not" to produce a "soft" version but rather an extraordinarily deep and detailed version which requires aggressive and careful processing. There are many "softer" versions available on the web. I did not wish to make another one.

RG

[nstahl]

Another great APOD; my congratulations to the provider.

Now I hope neufer or someone can point me to an understandable explanation of how a dying star can produce a barrel-shaped nebula. Surely the axis of the barrel must be the star's axis of rotation, and I can see material preferentially being expelled perpendicular to that (e.g. near the equator) but for a barrel-shape, material expelled far from the equator would have to be traveling faster than material near the equator. ??!

[KarelSculptor]

Earlier the Shapley Nebula was called a planet forming Ring nebula, as this one is called a ring nebula which to my opinion it is not. In an earlier discussion with Vincent Icke I proposed the idea that nebula's like M27, Shapley and also the Red Square Nebula are bipolar nebulas. (The material is expelled by the poles, not by the equator) . The form that is made in space is an hour glass (Hour Glass Nebula) or a diabolo, not a Ring. . In my discussion with Vincent Icke he claimed that he already described this for most nebulas.

[neufer]

<<Rafflesia arnoldii is a member of the GeNus RafflesIa. It is noted for producing the largest individual flower on earth, and a strong odor of decaying flesh - the latter point earning it the nickname of "corpse flower". It is an endemic plant that occurs only in the rainforests of Sumatra Island, Indonesia. Although there are some plants with larger flowering organs like the Titan Arum and Talipot palm, those are technically clusters of many flowers.

The flower of Rafflesia arnoldii grows to a diameter of around one meter and weighing up to 11 kilograms. It lives as a parasite on the Tetrastigma vine, which grows only in primary (undisturbed) rainforests. Rafflesia lacks any observable leaves, stems or even roots, yet is still considered a vascular plant. Similar to fungi, individuals grow as thread-like strands of tissue completely embedded within and in intimate contact with surrounding host cells from which nutrients and water are obtained. This plant produces no leaves, stems or roots and does not have chlorophyll. It can only be seen when it is ready to reproduce. Perhaps the only part of Rafflesia that is identifiable as distinctly plant-like are the flowers; although, even these are unusual since they attain massive proportions, have a reddish-brown coloration and stink of rotting flesh, which is why it was nicknamed the "corpse flower". This scent attracts insects such as flies which then pollinate the rare plant. It is not to be confused with the Titan Arum, Amorphophallus titanum, which is also commonly referred to as the "corpse flower".

Rafflesia arnoldii is rare and fairly hard to locate. It is especially difficult to locate the flower in forests as the buds take many months to develop and the flower lasts for just a few days. The flowers are unisexual and thus proximity of male and female flowers is vital for successful pollination. These factors make successful pollination a rare event.

When Rafflesia is ready to reproduce, a tiny bud forms on the outside of the root or stem and develops over a period of a year. The cabbage like head that develops, eventually opens to reveal the flower. The stigma or stamen are attached to a spiked disk inside the flower. A foul smell of rotting meat attracts flies and beetles to pollinate. To pollinate successfully, the flies and/or beetles must visit both the male and female plants. The fruit produced are round lots filled with smooth flesh including many thousands of hard coated seeds that are eaten and spread by tree shrews. How many of these plants still survive is unknown, but as the remaining primary forests of Borneo and Sumatra disappear, it can be assumed that their numbers are dwindling. Some environmentalists are developing ways to recreate the species' environment in an effort to stimulate their recovery. This has proved unsuccessful so far. Steps are also being taken to conserve the forests of Sumatra and Borneo. To help counter the over-collection of this rare plant, residents that have Rafflesia on their private property are encouraged to save the flowers and charge a small fee to see them.>>

[Anthony Barreiro]

This is a beautiful image. One thing I love about astrophotography is all the many different ways the same object can look, based on which wavelengths of visible light are used and/or how invisible radiation is represented using the colors of visible light. It's a lovely complement to the predominant shades of grey I see through the eyepiece of my little telescope!

[LocalColor]

Wonderful!

[emc]

I believe this is a conjunct out of the dead horse string.
Superb "conjunctivity" sir!

[neufer]

Now I hope neufer or someone can point me to an understandable explanation of how a dying star can produce a barrel-shaped nebula.

http://asterisk.apod.com/viewtopic.php? ... 07#p174053

Surely the axis of the barrel must be the star's axis of rotation

If the star has planets or is part of a binary star system there are other axes to consider.

and I can see material preferentially being expelled perpendicular to that (e.g. near the equator) but for a barrel-shape, material expelled far from the equator would have to be traveling faster than material near the equator. ??!

Plasma material expelled near the equator runs into a spiral labyrinth of magnetic fields.

[emc]

I believe this is a conjunct out of the dead horse string.
Superb "conjunctivity" sir!

Sorry Art – I meant to say “ALSO” (actually I thought I had until I reviewed it just now… Grrrr!)