Its main ring contains knots of nebulosity, which have now been detected in several nearby planetary nebulae, especially those with a molecular envelope like the Ring nebula and the Dumbbell Nebula. The Helix Nebula was the first planetary nebula discovered to contain cometary knots. Knots A closer view of knots in the nebula Spectroscopically, the outer ring's expansion rate is 40 km/s, and about 32 km/s for the inner disk. Įxpansion of the whole planetary nebula structure is estimated to have occurred in the last 6,560 years, and 12,100 years for the inner disk. The outer-most ring appears flattened on one side due to it colliding with the ambient interstellar medium. The size of the inner disk is 8×19 arcmin in diameter (0.52 pc) the outer torus is 12×22 arcmin in diameter (0.77 pc) and the outer-most ring is about 25 arcmin in diameter (1.76 pc). The Helix Nebula is thought to be shaped like a prolate spheroid with strong density concentrations toward the filled disk along the equatorial plane, whose major axis is inclined about 21° to 37° from our vantage point. Structure A 3 dimensional map of carbon monoxide in NGC 7293 Structure and cometary knots are prominent in this Infrared false-color image taken by the Spitzer Space Telescope The location of NGC 7293 (labelled in red) −1200 years, based on the ratio of its size to its measured expansion rate of 31 km The nebula is in the constellation of Aquarius, and lies about 650 light-years away, spanning about 0.8 parsecs (2.5 light-years). The observed glow of the central star is so energetic that it causes the previously expelled gases to brightly fluoresce. The remnant central stellar core, known as the central star (CS) of the planetary nebula, is destined to become a white dwarf star. Gases from the star in the surrounding space appear, from our vantage point, as if we are looking down a helix structure. The Helix Nebula is an example of a planetary nebula, formed by an intermediate to low-mass star, which sheds its outer layers near the end of its evolution. The Helix Nebula has sometimes been referred to as the "Eye of God" in pop culture, as well as the " Eye of Sauron". 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 distance, measured by the Gaia mission, is 655☑3 light-years. 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 Helix Nebula (also known as NGC 7293 or Caldwell 63) is a planetary nebula (PN) located in the constellation Aquarius. M104 can be seen with a small telescope in the direction of the constellation Virgo.NGC 7293 seen through several visible filters by Hubble Space Telescope The Sombrero Galaxy, also known as M104, spans about 50,000 light years across and lies 28 million light years away. The featured image, digitally sharpened, shows the infrared glow, recently recorded by the orbiting Spitzer Space Telescope, superposed in false-color on an existing image taken by NASA's Hubble Space Telescope in visible light. The dark band of dust that obscures the mid-section of the Sombrero Galaxy in optical light actually glows brightly in infrared light. In fact, it is a galaxy - or at least part of one: the photogenic Sombrero Galaxy, one of the largest galaxies in the nearby Virgo Cluster of Galaxies. Kennicutt (Steward Obs.) et al., SSC, JPL, Caltech, NASAĮxplanation: This floating ring is the size of a galaxy. Astronomy Picture of the Day - The Sombrero Galaxy in Infrared
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