Did JWST catch the Ring Nebula forming new planets?

When our Sun dies, we expect many planets to go with it.

After its formation some 4.6 billion years ago, the Sun has grown in radius by approximately 14%. It will continue to grow, doubling in size when it becomes a subgiant, but it will increase in size by more than ~100-fold when it becomes a true red giant in another ~7-8 billion years, total, all while growing in brightness by a factor of at least a few hundred.

After running out of its core hydrogen, it will expand into a red giant.

Mercury, Venus, and likely Earth will all be devoured.

During the main phase of a star’s life, planets can orbit at nearly any distance from it, including very close in. As the star evolves, it becomes a subgiant and eventually a true giant. As the star increases in size, the frictional drag force on the innermost planet increases; eventually, it will come into contact with and be devoured by the parent star, while the increased stellar brightness has severe consequences for planetary atmospheres and ice-rich objects.

Mass loss will eject the Oort cloud, Kuiper belt, and possibly even Neptune and Uranus.

When our Sun runs out of fuel, it will become a red giant, followed by a planetary nebula with a white dwarf at the center. The Cat’s Eye Nebula is a visually spectacular example of this potential fate, with the intricate, layered, asymmetrical shape of this particular one suggesting a binary companion. At the center, a young white dwarf heats up as it contracts, reaching temperatures tens of thousands of Kelvin hotter than the surface of the red giant that spawned it. The hottest young white dwarf surfaces reach ~150,000 K.

Finally, a remnant white dwarf will form, ionizing the previous ejecta.

When the central star in a dying stellar system heats up to about temperatures of ~30,000 K, it becomes hot enough to ionize the previously ejected material, creating a true planetary nebula in the case of a Sun-like star. Here, NGC 7027 has just recently crossed that threshold, and is still rapidly expanding. At just ~0.1-to-0.2 light-years across, it is one of the smallest and youngest planetary nebulae known.

But the story may not end there, according to shocking new JWST research.

The Ring Nebula can be found just inside the Summer Triangle in the constellation of Lyra: just south of the brightest star, Vega. Found in between the 2nd and 3rd brightest stars in Lyra’s constellation, the imaginary line connecting the blue giant stars Sheliak and Sulafat contains the Ring Nebula, circled in red, which can be spotted even with a pair of off-the-shelf binoculars.

Back in 2023, JWST first observed the Ring Nebula.

The mid-infrared (JWST MIRI) view of the Ring Nebula showcases the diffuse, low-density gas inside the nebula, the extended filaments emerging outward from the main ring, and the concentric ring features that are likely carved by a binary companion to the Ring Nebula, yet undiscovered, but which may be located at the same distance that our Solar System’s Kuiper belt is found from our Sun. JWST NIRCam and Hubble optical data is also available for this object.

Just ~2000 light-years away, it’s the closest planetary nebula to Earth.

Outside of the main features seen in the Ring Nebula, thin, wispy, outermore populations of gas, mostly hydrogen gas, are revealed by the Large Binocular Telescope at Mount Graham International Observatory. By combining data from multiple observatories, composite images revealing unprecedented features can be constructed.

It possesses a ring, lobes, plus inner and outer halos.

This schematic shows the geometry and structure of the Ring Nebula (Messier 57) as it would appear if viewed from the side, rather than along our line-of-sight. This shows the nebula’s wide halo, inner region, lower-density lobes of material stretching toward and away from us, and the prominent, glowing disc. New data from JWST (in infrared light) and the SMA (in radio light) has further revealed new features, such as a large central dust cloud within the nebula.

Inside, many different chemical compounds can be spotted.

This three-panel animation fades between visible light (Hubble) views, near-infrared (JWST NIRCam) views, and even cooler mid-infrared (JWST MIRI) views. This planetary nebula is one of the most well-studied in all of history, yet JWST can still reveal features never seen before.

Ionized carbon monoxide reveals polar flows inside a barrel-shaped shell of material.

By tracing the features of different species of gaseous and ionized molecules, scientists can reconstruct a variety of features found around and within the famed Ring Nebula. They include a barrel-shaped “ring” of heated material that’s about 6000 years old, with a tilted, younger polar outflow blowing out along the “long axis” of the nebula’s configuration.

The dying star’s remnant is centrally located, but a long-suspected companion star remains elusive.

By leveraging the infrared JWST (left) and radio-wave Submillimeter Array (right) data together, one can determine where the central remnant star that created the Ring Nebula must be. The two inferred locations aren’t identical, indicating a potential companion star playing a role in the creation of this nebula.

That’s why new JWST research, focusing on the Ring Nebula’s interior and central regions, is vitally important.

These MIRI images from JWST show the extended nebular emission around the central star at the heart of the Ring Nebula. Long wavelengths, in particular, suggest a very large dust cloud and hint at the presence of a flat, dusty disk.

The central star is surrounded by a compact dust cloud, revealed at long wavelengths (above ~5 microns).

The central star, on its way to becoming a white dwarf, at the heart of the Ring Nebula as shown in various wavelengths by Hubble (top row) and JWST (bottom two rows). The new detection of a neutral dust cloud thousands of AU wide has tremendous implications for potential late-time planet formation.

These dusty features resemble young protoplanetary and dusty debris disks.

This image, from ALMA, shows the protoplanetary disk around HL Tauri. The gaps within the disk correspond to the locations of newly-forming planets, and emit jets and outflows (not shown) associated with Herbig-Haro 150: part of the same system. Where massive disks containing heavy elements arise around stars, new massive objects, including planets, can form.

This may mark a new, unforeseen planet-forming phase.

Earth-sized planets in inner orbits have been spotted once before around white dwarf stars through microlensing studies, but new research suggests it might not be because a world like Earth can survive, but rather because new planets can form around young white dwarfs.

Perhaps white dwarf systems spawn new planets, even after dying.

When Sun-like stars run out of fuel, they blow off their outer layers in a planetary nebula, with the center contracting down to form a white dwarf, which takes a very long time to fade to darkness. The planetary nebula our Sun will generate should fade away completely, with only the white dwarf and the surviving planets and asteroids remaining after another ~9.5 billion years. However, a new planet-forming disk may arise, giving rise to potential new worlds.

Mostly Mute Monday tells an astronomical story in images, visuals, and no more than 200 words.