Helix Nebula

At a glance

Key points

Its inner edge is lined with thousands of comet-shaped knots of gas.

• Nearest bright planetary nebula
• Thousands of comet-like knots
• About 650 light-years away

Cometary knots

Dense clumps of gas are shadowed from the central white dwarf's wind, trailing tails away from it like comets.

Close, large and faint

Karl Ludwig Harding discovered the Helix in 1823. Because it is so near, it covers nearly half the width of the full Moon, and its bright ring stretches nearly three light-years, with fainter loops reaching farther out. That light is spread thin: its total brightness is about magnitude 7.3, but its surface is dim, so it is easier to find with binoculars or a low-power telescope under dark skies than at high magnification.

Inside a knot

Each knot is a dense clump in gas the star shed earlier, now being overtaken by a fast, hot wind from the exposed core. The heads are at least twice the size of our Solar System, and the tails stream about 160 billion km away from the centre. Thousands line the inner edge of the ring. Whether they were clumpy from the start or broke up when the hot wind arrived is still debated.

What Webb showed

Webb's NIRCam close-up, released in January 2026, uses colour as a thermometer. Blue marks the hottest gas, nearest the white dwarf; yellow shows cooler zones where hydrogen atoms pair into molecules; red traces the coldest material at the outer edge, where dust can form. The knots act as sheltered pockets in which more complex molecules can begin to build up. The white dwarf itself lies just outside the frame.

Observing it

The Helix lies in Aquarius and is best seen on September and October evenings. For northern observers it stays low in the southern sky; from the southern hemisphere, where it is a spring object, it climbs much higher. A dark site matters more than aperture: a wide-field view shows a pale, round glow with a darker centre.

Missions

1. 1990–

   Hubble Space Telescope

   NASA / ESAActive

   Ultraviolet to near-infrared imaging from low Earth orbit.

   Mission page (opens in a new tab)

2. 2021–

   James Webb Space Telescope

   NASA / ESA / CSAActive

   Infrared observatory at Sun–Earth L2, about 1.5 million km from Earth.

   Mission page (opens in a new tab)

Related entries

• Ring NebulaM57 · a dying Sun-like star

Sources

1. NASA Science: Webb: Helix Nebula (opens in a new tab)
2. NASA Science: Hubble Caldwell catalog: Caldwell 63 (opens in a new tab)

Last reviewed 10 Oct 2026 against these sources. Built from public NASA, ESA and JPL data; not affiliated with or endorsed by any agency.