Question: When is the Sun expected to spawn into a nebula?
About the article "Nebula", section "Planetary nebulae".

Candidate passages:
Planetary nebulae form from the gaseous shells that are ejected from low-mass asymptotic giant branch stars when they transform into white dwarfs.
They are emission nebulae with spectra similar to those of emission nebulae found in star formation regions.
Technically they are HII regions, because most hydrogen will be ionized, but they are denser and more compact than the nebulae in star formation regions.
Planetary nebulae were given their name by the first astronomical observers who became able to distinguish them from planets, who tended to confuse them with planets, of more interest to them.
Our Sun is expected to spawn a planetary nebula about 12 billion years after its formation.
Astronomers divide nebulae into four major groups, all of which are represented in the sections that follow:  Diffuse nebulae.
Most nebulae can be described as diffuse nebulae, which means that they span extended areas and are not circumscribed by well-defined boundaries.
In visible light these nebulae may be further divided into emission and reflection nebulae.
Emission nebulae emit spectral line radiation from ionized gas, principally hydrogen (H II), with a predominant red emission line at 656 nm.
Reflection nebulae do not themselves emit significant amounts of visible light, but are near stars and reflect light from them, with blue light being the most efficiently scattered.
Planetary nebulae.
Planetary nebulae form from the gaseous shells that are ejected from low-mass red giant stars as they transform into white dwarfs.
The Sun is expected to spawn a planetary nebula about 12 billion years after its formation.
Supernova remnants.
A supernova occurs when a high-mass star reaches the end of its life: When nuclear fusion in the core of the star stops, the star collapses.
The gas falling inward either rebounds or gets so strongly heated that it expands outwards from the core, thus causing the star to explode.
The expanding shell of gas forms a supernova remnant, a special type of diffuse nebula.
Dark nebulae.
A dark nebula is a type of diffuse nebula that is so dense it obscures the light from a background emission or reflection nebula (for example, the Horsehead Nebula) or it blocks out background stars (for example, the Snake Nebula).  
Dos EPs is a compilation album by rock trio Nebula.
It contains the Nebula songs from the Nebula/Lowrider EP, Sun Creature EP and 3 new songs. 
The Double Helix Nebula is a gaseous nebula near the center of our galaxy.
It is thought to have been distorted by magnetic torsion into the shape of two connected spirals, known popularly as a double helix, akin to the shape of DNA.
The nebula was discovered by the Spitzer Space Telescope.
The segment seen so far is thought to be 80 light years long, 300 light years from the supermassive black hole thought to be at the galaxy's center, and 25,000 light years from Earth.
This nebula is seen as circumstantial evidence that the magnetic fields at the center of the galaxy are extremely strong, more than 1,000 times stronger than those of the Sun.
If so, they may be driven by the massive disc of gas orbiting the central supermassive black hole.
The Double Helix Nebula should not be confused with the Helix Nebula, a planetary nebula only 650 light years from Earth. 
Minkowski 2-9, abbreviated M2-9 (and also known as Minkowski's Butterfly, the Wings of a Butterfly Nebula or just Butterfly Nebula, and Twin Jet Nebula) is a planetary nebula that was discovered by Rudolph Minkowski in 1947.
It is located about 2,100 light-years away from Earth in the direction of the constellation Ophiuchus.
This bipolar nebula takes the peculiar form of twin lobes of material that emanate from a central star.
Astronomers have dubbed this object as the "Twin Jet Nebula" because of the polar jets believed to cause the shape of the lobes.
Its form also resembles the wings of a butterfly.
The nebula was imaged by the Hubble Space Telescope in the 1990s.M2-9 represents the spectacular “last gasp” of a binary star system at the nebula's center.
The primary component of this binary is the hot core of a star that reached the end of its main-sequence life cycle, ejected most of its outer layers and became a red giant, and is now contracting into a white dwarf.
It is believed to have been a sun-like star early in its life.
The second, smaller star of the binary orbits very closely and may even have been engulfed by the other's expanding stellar atmosphere with the resulting interaction creating the nebula.
Astronomers theorize that the gravity of one star pulls some of the gas from the surface of the other and flings it into a thin, dense disk extending into space.
Such a disk can successfully account for the jet-exhaust-like appearance of M2-9.
The nebula has inflated dramatically due to a fast stellar wind, blowing out into the surrounding disk and inflating the large, wispy hourglass-shaped wings perpendicular to the disk.
These wings produce the butterfly appearance when seen in projection.
The outer shell is estimated to be about 1,200 years old .]