A planetary nebula is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives.
The Ring Nebula is a planetary nebula in the northern constellation of Lyra. Such a nebula is formed when a star, during the last stages of its evolution before becoming a white dwarf, expels a vast luminous envelope of ionized gas into the surrounding interstellar space.
The Helix Nebula is a planetary nebula (PN) located in the constellation Aquarius. Discovered by Karl Ludwig Harding, most likely before 1824, this object is one of the closest of all the bright planetary nebulae to Earth. The distance, measured by the Gaia mission, is 655±13 light-years. It is similar in appearance to the Cat's Eye Nebula and the Ring Nebula, whose size, age, and physical characteristics are similar to the Dumbbell Nebula, varying only in its relative proximity and the appearance from the equatorial viewing angle. The Helix Nebula has sometimes been referred to as the "Eye of God" in pop culture, as well as the "Eye of Sauron".
The Cat's Eye Nebula is a planetary nebula in the northern constellation of Draco, discovered by William Herschel on February 15, 1786. It was the first planetary nebula whose spectrum was investigated by the English amateur astronomer William Huggins, demonstrating that planetary nebulae were gaseous and not stellar in nature. Structurally, the object has had high-resolution images by the Hubble Space Telescope revealing knots, jets, bubbles and complex arcs, being illuminated by the central hot planetary nebula nucleus (PNN). It is a well-studied object that has been observed from radio to X-ray wavelengths.
The Dumbbell Nebula is a planetary nebula in the constellation Vulpecula, at a distance of about 1360 light-years. It was the first such nebula to be discovered, by Charles Messier in 1764. At its brightness of visual magnitude 7.5 and diameter of about 8 arcminutes, it is easily visible in binoculars and is a popular observing target in amateur telescopes.
The North America Nebula is an emission nebula in the constellation Cygnus, close to Deneb. The shape of the nebula resembles that of the continent of North America, complete with a prominent Gulf of Mexico.
The Eskimo Nebula, also known as the Clown-faced Nebula, Lion Nebula, or Caldwell 39, is a bipolar double-shell planetary nebula (PN). It was discovered by astronomer William Herschel in 1787. The formation resembles a person's head surrounded by a parka hood. It is surrounded by gas that composed the outer layers of a Sun-like star. The visible inner filaments are ejected by a strong wind of particles from the central star. The outer disk contains unusual, light-year-long filaments.
The Saturn Nebula is a planetary nebula in the constellation Aquarius. It appears as a greenish-yellowish hue in a small amateur telescope. It was discovered by William Herschel on September 7, 1782, using a telescope of his own design in the garden at his home in Datchet, England, and was one of his earliest discoveries in his sky survey. The nebula was originally a low-mass star that ejected its layers into space, forming the nebula. The central star is now a bright white dwarf star of apparent magnitude 11.5. The Saturn Nebula gets its name from its superficial resemblance to the planet Saturn with its rings nearly edge-on to the observer. It was so named by Lord Rosse in the 1840s, when telescopes had improved to the point that its Saturn-like shape could be discerned. William Henry Smyth said that the Saturn Nebula was one of Struve's nine "Rare Celestial Objects".
NGC 5189 is a planetary nebula in the constellation Musca. It was discovered by James Dunlop on 1 July 1826, who catalogued it as Δ252. For many years, well into the 1960s, it was thought to be a bright emission nebula. It was Karl Gordon Henize in 1967 who first described NGC 5189 as quasi-planetary based on its spectral emissions.
NGC 7027, also known as the Jewel Bug Nebula, is a very young and dense planetary nebula located around 3,000 light-years from Earth in the constellation Cygnus. Discovered in 1878 by Édouard Stephan using the 800 mm (31 in) reflector at Marseille Observatory, it is one of the smallest planetary nebulae and by far the most extensively studied.
NGC 3132 is a bright and extensively studied planetary nebula in the constellation Vela. Its distance from Earth is estimated at about 613 pc. or 2,000 light-years.
Sh2-279 is an HII region and bright nebulae that includes a reflection nebula located in the constellation Orion. It is the northernmost part of the asterism known as Orion's Sword, lying 0.6° north of the Orion Nebula. The reflection nebula embedded in Sh2-279 is popularly known as the Running Man Nebula.
NGC 6302 is a bipolar planetary nebula in the constellation Scorpius. The structure in the nebula is among the most complex ever observed in planetary nebulae. The spectrum of NGC 6302 shows that its central star is one of the hottest stars known, with a surface temperature in excess of 250,000 degrees Celsius, implying that the star from which it formed must have been very large.
NGC 6751, also known as the Glowing Eye Nebula or the Dandelion Puffball Nebula, is a planetary nebula in the constellation Aquila. It is estimated to be about 6,500 light-years away.
The Veil Nebula is a cloud of heated and ionized gas and dust in the constellation Cygnus.
NGC 7662 is a planetary nebula located in the constellation Andromeda.
NGC 2261 is a variable nebula located in the constellation Monoceros. The nebula is illuminated by the star R Monocerotis, which is not directly visible itself.
NGC 2371-2 is a dual lobed planetary nebula located in the constellation Gemini. Visually, it appears like it could be two separate objects; therefore, two entries were given to the planetary nebula by John Louis Emil Dreyer in the New General Catalogue, so it may be referred to as NGC 2371, NGC 2372, or variations on this name. It has also been called the double bubble nebula.
NGC 3242 is a planetary nebula located in the constellation Hydra.
NGC 1501 is a complex planetary nebula located in the constellation of Camelopardalis, discovered in 27 Aug 1787 by William Herschel. It is also known as the Oyster Nebula.
