When is a planetary nebula formed

In the case of our Sun, the planet Mercury will be absorbed along with Venus and Earth may be engulfed or thrown from its current orbit in the process. Since the star has the same amount of material, its heat will be spread over a larger surface area and thus it will be cooler, take on a reddish hue and become a star that is called Red Giant. Illustration credit: Don Dixon Cosmographia Phase 3- The Long Good-bye As was the case with hydrogen, the amount of helium in the core will eventually become exhausted.

When this happens, gravity will cause the surface of the star to suddenly shrink as it simultaneously exerts enormous pressure on the carbon and oxygen core. However, in a star like our Sun, core temperatures will never become sufficient to trigger the fusion of carbon and oxygen into the next heavier elements.

It will only succeed in triggering fusion of the helium shell surrounding the core. When thermonuclear reactions within the shell of helium commences, the outward radiation pressure will exceed the inward pull of gravity and the surface of star will expand once again returning the star to its Red Giant size.

However, this time, the force of gravity will be insufficient to stop the expansion. The ejected gas will begin to visibly glow in harlequin colors as it is ionized by invisible ultraviolet radiation still being released from the star's hot core.

As the star's outer surface material departs the core will be progressively exposed. When the core of a star is revealed in this manner, the star is called a white dwarf. These stars are fantastically dense compared to anything on Earth, weighing over a ton per teaspoonful. Over billions of years, the core will slowly cool, cease to release any radiation and become a black dwarf - the corpse of a Sun that once was.

If the star had a family of planets, those that weren't devoured or ejected from their solar system during its Red Giant phase will freeze. It wasn't until the mids that Charles Messier, the famous French comet hunter, noticed its distant faint fuzzy circular glow and placed it in his catalog to prevent him from mistaking it as a comet during future night sky expeditions. A few years later, the musician turned astronomer named William Herschel gave these objects their name because of their resemblance to planets.

Telescopes back then lacked the color definition and clarity of even the most inexpensive instruments available today. So, both Messier and Herschel would most likely be astonished had they lived to enjoy our current view of this planetary nebula. Today, we know Messier's 27th catalog designation as the Dumbbell nebula. Located about 1, light years from Earth. At that distance, our sun would appear times fainter than the nebula. We happen to view the Dumbbell along its equator.

If our line of site were more to its poles, our impression of the Dumbbell might be that of a ring. The Dumbbell is approximately half a light year in diameter but even at this great distance, the nebula appears quite large- equivalent to about half the diameter of the full Moon. Our galaxy contains over billion stars but only about 3, are surrounded by a planetary nebula.

Planetary nebulae are usually no larger than a light-year in diameter which is actually enormous if you consider a light-year is almost 6 trillion miles in length. For more information about the colors in nebulae, see this example of a PN in a globluar cluster. Abell NGC Ring Nebula. Saturn Nebula.

These rocky worlds have an ultra-thin outer brittle layer and little to no topography. Such worlds After studying the chemical composition of 'polluted' Scientists have developed a They argue that Algol has many companion stars which have not been detected from earlier Near-Earth Asteroid a Mini-Moon?

Print Email Share. Most Popular Stories. New technology has captured a number of phenomenal images of planetary nebulae in extreme depth.

In doing so, it has revealed the complexities that could occur at the end of the life of the sun. Where scientists once thought that the gaseous layers came off evenly, images from the Hubble Space Telescope have revealed a wide array of possibilities that could be the fate of our closest star. Dumbbell Nebula M27 : The first recorded planetary nebula, the Dumbbell Nebula lies 1, light-years away from Earth. Ring Nebula M57 : The almost-perfect ring-like shape made naming M57 a no-brainer.

The diffuse shell of gas and dust spread almost evenly after they were shucked off of their parent star. NGC When William Herschel saw the bright star in the heart of this planetary nebula, he realized that he wasn't looking at clusters but through gas and dust.

As a result, he coined the name "planetary nebula," because they shared the coloration of the recently discovered Uranus. Stingray Nebula Hen : The youngest known planetary nebula, Hen is as large as solar systems.