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NGC 3132 (also known as the Eight-Burst Nebula, [2] the Southern Ring Nebula, [2] or Caldwell 74) is a bright and extensively studied planetary nebula in the constellation Vela. Its distance from Earth is estimated at 613 pc or 2,000 light-years .
NGC 6826 (also known as Caldwell 15) is a planetary nebula located in the constellation Cygnus. It is commonly referred to as the "Blinking Planetary", although many other nebulae exhibit such "blinking". When viewed through a small telescope, the brightness of the central star overwhelms the eye when viewed directly, obscuring the surrounding ...
NGC 6741, also known as the Phantom Streak Nebula, is located about 7000 light-years away in the constellation of Aquila (the Eagle). NGC 6741 is classed as a planetary nebula, though no planets are responsible for this billowy cloud; the term came about in the 18th century because the round gas shells resembled the Solar System's outer giant planets in astronomers' telescopes.
A typical planetary nebula is roughly one light year across, and consists of extremely rarefied gas, with a density generally from 100 to 10,000 particles per cm 3. [42] (The Earth's atmosphere, by comparison, contains 2.5 × 10 19 particles per cm 3.) Young planetary nebulae have the highest densities, sometimes as high as 10 6 particles per ...
NGC 2440 is a planetary nebula, one of many in our galaxy. Its central star, HD 62166, [1] is possibly the hottest known white dwarf, about 400,000°F(200,000°C). The nebula is situated in the constellation Puppis. It was discovered by William Herschel on March 4, 1790. He described it as "a beautiful planetary nebula of a considerable degree ...
NGC 3918 is a bright planetary nebula in the constellation Centaurus, nicknamed the "Blue Planetary" or "The Southerner". It is the brightest of the far southern planetary nebulae. This nebula was discovered by Sir John Herschel in March 1834 and is easily visible through small telescopes.
NGC 6309, also known as the Box Nebula, is a planetary nebula located in the constellation Ophiuchus. It was discovered by the German astronomer Wilhelm Tempel in 1876. [4] It has a luminosity of about 1800 times that of the Sun. [1] [2] [5] The distance to this nebula is not well known, but it is assumed to be about 6,500 light-years or 2,000 ...
NGC 5189 (Gum 47, IC 4274, nicknamed Spiral Planetary Nebula) is a planetary nebula in the constellation Musca. It was discovered by James Dunlop on 1 July 1826, who catalogued it as Δ252. [ 1 ] For many years, well into the 1960s, it was thought to be a bright emission nebula.