APOD: Rings Around the Ring Nebula (2024 Apr 28)

[APOD Robot]

Rings Around the Ring Nebula

Explanation: The Ring Nebula (M57) is more complicated than it appears through a small telescope. The easily visible central ring is about one light-year across, but this remarkably deep exposure - a collaborative effort combining data from three different large telescopes - explores the looping filaments of glowing gas extending much farther from the nebula's central star. This composite image includes red light emitted by hydrogen as well as visible and infrared light. The Ring Nebula is an elongated planetary nebula, a type of nebula created when a Sun-like star evolves to throw off its outer atmosphere and become a white dwarf star. The Ring Nebula is about 2,500 light-years away toward the musical constellation Lyra.

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[Christian G.]

Had Messier discovered this planetary nebula with the same fine details seen here, I'm sure he would have ditched the term "planetary" nebula right away! We read over and over that it's a misnomer; what would be a better term? Red giant remnant?

[Chris Peterson]

Had Messier discovered this planetary nebula with the same fine details seen here, I'm sure he would have ditched the term "planetary" nebula right away! We read over and over that it's a misnomer; what would be a better term? Red giant remnant?

I've always liked the term, and wouldn't label it a "misnomer". "Planetary" is simply an adjective describing the general planet-like appearance of most of these objects through a telescope. It reflects a bit of astronomical history. And we have plenty of words these days that stem from earlier understanding and would be "wrong" if taken literally. Including "nebula" for that matter!

[Sa Ji Tario]

The instruments of the observers of the 16th and 17th centuries were less precise than the 150 mm amateur telescopes, but with the desire to discover they solved it. When the Ring Nebula is observed with an amateur telescope, a milky circle appears to the eye with a dark center and nothing more resolution, but since we know that is what we are looking at...

[Chris Peterson]

The instruments of the observers of the 16th and 17th centuries were less precise than the 150 mm amateur telescopes, but with the desire to discover they solved it. When the Ring Nebula is observed with an amateur telescope, a milky circle appears to the eye with a dark center and nothing more resolution, but since we know that is what we are looking at...

Even those who originally coined and used the term knew they weren't looking at planets.

[Roy]

Interesting adjective "elongated". Implies ovoid, but outermost wisps are almost perfectly circular. We do not know the viewing aspect. Could be looking down the barrel of somethig like the butterfly nebula.

[Chris Peterson]

Interesting adjective "elongated". Implies ovoid, but outermost wisps are almost perfectly circular. We do not know the viewing aspect. Could be looking down the barrel of somethig like the butterfly nebula.

In fact, we understand both the viewing aspect and the 3D structure of the Ring Nebula quite well.
_

Click to play embedded YouTube video.

[johnnydeep]

So, something similar will likely be the fate of our own Sun, correct? From the link -

Planetary Nebulae
Planetary nebulae (PN) represent the last stages of evolution for low- and intermediate-mass stars whose Main Sequence mass was less than about 8 solar masses. After evolving through the Asymptotic Giant Branch (AGB) on the Hertzsprung-Russell diagram, a phase characterised by shell burning resulting in radial pulsations that drive prodigious mass-loss, these stars possess thick, dusty, molecular circumstellar envelopes. In the rapid (few x 1000 yr) post-AGB or proto-planetary nebula (PPN) phase, the mass loss drops dramatically and the circumstellar envelope detaches from the star. The ejection of the envelope exposes the evolving progenitor star which is increasing in temperature and on its way to becoming a white dwarf. Once the central star temperature reaches ~30,000 K, it emits most of its radiation in the ultraviolet region. This radiation ionises the remnant circumstellar envelope, producing the optically-visible planetary nebula. The planetary nebula is still expanding however, and eventually its material will disperse into space, leaving the exposed white dwarf.

[Chris Peterson]

So, something similar will likely be the fate of our own Sun, correct? From the link -

Planetary Nebulae
Planetary nebulae (PN) represent the last stages of evolution for low- and intermediate-mass stars whose Main Sequence mass was less than about 8 solar masses. After evolving through the Asymptotic Giant Branch (AGB) on the Hertzsprung-Russell diagram, a phase characterised by shell burning resulting in radial pulsations that drive prodigious mass-loss, these stars possess thick, dusty, molecular circumstellar envelopes. In the rapid (few x 1000 yr) post-AGB or proto-planetary nebula (PPN) phase, the mass loss drops dramatically and the circumstellar envelope detaches from the star. The ejection of the envelope exposes the evolving progenitor star which is increasing in temperature and on its way to becoming a white dwarf. Once the central star temperature reaches ~30,000 K, it emits most of its radiation in the ultraviolet region. This radiation ionises the remnant circumstellar envelope, producing the optically-visible planetary nebula. The planetary nebula is still expanding however, and eventually its material will disperse into space, leaving the exposed white dwarf.

I would not say "fate". But this will be a step in the evolution of the Sun into a white dwarf.

[johnnydeep]

So, something similar will likely be the fate of our own Sun, correct? From the link -

Planetary Nebulae
Planetary nebulae (PN) represent the last stages of evolution for low- and intermediate-mass stars whose Main Sequence mass was less than about 8 solar masses. After evolving through the Asymptotic Giant Branch (AGB) on the Hertzsprung-Russell diagram, a phase characterised by shell burning resulting in radial pulsations that drive prodigious mass-loss, these stars possess thick, dusty, molecular circumstellar envelopes. In the rapid (few x 1000 yr) post-AGB or proto-planetary nebula (PPN) phase, the mass loss drops dramatically and the circumstellar envelope detaches from the star. The ejection of the envelope exposes the evolving progenitor star which is increasing in temperature and on its way to becoming a white dwarf. Once the central star temperature reaches ~30,000 K, it emits most of its radiation in the ultraviolet region. This radiation ionises the remnant circumstellar envelope, producing the optically-visible planetary nebula. The planetary nebula is still expanding however, and eventually its material will disperse into space, leaving the exposed white dwarf.

I would not say "fate". But this will be a step in the evolution of the Sun into a white dwarf.

Ok, agreed. The Sun would be merely senescent, but not yet entirely dead!

[zendae]

So, something similar will likely be the fate of our own Sun, correct? From the link -

I would not say "fate". But this will be a step in the evolution of the Sun into a white dwarf.

Ok, agreed. The Sun would be merely senescent, but not yet entirely dead!

Maybe these stars are quite comfortable in anticipation; a ripening chrysalis perhaps.

[wilddouglascounty]

With the added detail, it reminds me of a single peony

[Christian G.]

I would not say "fate". But this will be a step in the evolution of the Sun into a white dwarf.

Ok, agreed. The Sun would be merely senescent, but not yet entirely dead!

Maybe these stars are quite comfortable in anticipation; a ripening chrysalis perhaps.

The ripening is only beginning, give them a quadrillion years and white dwarfs apparently turn into giant diamonds! Which of course are forever.

https://www.livescience.com/space/cosmo ... e-our-eyes

[Bird_Man]

Are the different "rings" shown in this image from successive shedding events when it "evolves to throw off it's outer atmosphere"?

[Chris Peterson]

Are the different "rings" shown in this image from successive shedding events when it "evolves to throw off it's outer atmosphere"?

Most likely.

[johnnydeep]

Ok, agreed. The Sun would be merely senescent, but not yet entirely dead!

Maybe these stars are quite comfortable in anticipation; a ripening chrysalis perhaps.

The ripening is only beginning, give them a quadrillion years and white dwarfs apparently turn into giant diamonds! Which of course are forever.

diamond star.png
https://www.livescience.com/space/cosmo ... e-our-eyes

Cool. And apparently, this Earth-sized diamond will have a refreshing crystalized oxygen core at its center!

Devoid of nuclear burning, a white dwarf is thought to exist as a homogeneous mixture of carbon and oxygen whose nuclei are liquid. (In the star’s ionized-plasma state, the electrons remain a Fermi gas and the nuclei are either liquid or solid.) When the nuclei freeze, the elements start segregating. Oxygen nuclei carry a higher charge than carbon, so they are the first to solidify—into a body-centered-cubic metal, according to calculations. Oxygen also has a higher density than carbon, and after nucleating, it “snows out” of the liquid and sinks to the core.

But sadly, even this awesome diamond won't be forever:

10³⁰ (1 nonillion) years from now
The estimated time until most or all of the remaining 1–10% of stellar remnants not ejected from galaxies fall into their galaxies' central supermassive black holes. By this point, with binary stars having fallen into each other, and planets into their stars, via emission of gravitational radiation, only solitary objects (stellar remnants, brown dwarfs, ejected planetary-mass objects, black holes) will remain in the universe.[9]

2×10³⁶ (2 undecillion) years from now
The estimated time for all nucleons in the observable universe to decay, if the hypothesized proton half-life takes its smallest possible value (8.2 × 10³³ years).[142][143][note 4]

10³⁶–10³⁸ (1–100 undecillion) years from now
Estimated time for all remaining planets and stellar-mass objects, including the Sun, to disintegrate if proton decay can occur.[9]