Astrophoto: The Witch Head Nebula by Richard Payne
Written by R. Jay Gabany
Since 1989, when the first extra solar planet was detected, 180 planetary systems featuring 210 planets have been identified as of October 19, 2006. Each discovery has been a remarkable achievement. However, not one of these worlds has yet to be observed visually and there is not a shred of evidence that any are capable of harboring life, as we know it. But that has not throttled the creative energy of writers, television producers and movie directors from their unbridled speculation that the Universe is bursting with intelligent beings. In fact, the unprecedented discovery of these planets has seemed somewhat anticlimactic to science fiction fans raised on H.G. Wells, Gene Roddenberry and George Lucas tales. To many sci-fi buffs, science is simply confirming their long held beliefs. For example, according to the Star Trek universe, Rigel, the off camera star which illuminates the accompanying picture, has twelve planets that support Federation colonies.
Other stars have been used in fiction as a hypothetical setting. Using scientific information is a key ingredient for spinning science fiction yarns that are enthralling. Additionally, like Jonathan Swift's classic Gulliver's Travels, the best sci-fi narratives are also constructed from a robust imagination reinforced with ties that bind the story to the present. As a result, many space enthusiasts view the night sky as a stage filled with incredible adventures. They gaze upon a star and think about their favorite characters overcoming familiar adversities in the great beyond.
Unfortunately, extra solar planets have yet to be discovered around Rigel. It's the brilliant, blue-white star at the left foot of Orion, the hunter constellation straddling the north and south celestial equator in the evening night sky during winter. Rigel is about 70 times larger than our Sun, releases 80,000 times more energy (if you include the invisible ultra-violet radiation pouring from its interior furnace) and has double the surface temperature. In short, this star is a monster by any definition! Located about 800 light years from Earth (a light year is about ten trillion kilometers or six trillion miles), Rigel is extremely far away yet it is the seventh brightest star in our view of the heavens easily outshining others that have a fraction of that distance.
Rigel is a supergiant star and because of its extreme mass, it will also have a much shorter life span than the one we orbit. In fact, Rigel is already in the process of dying. Most of its hydrogen has already been fused into helium. Now, that material is being used as fuel within the bowls of the star's furnace and it's being changed into heavier elements like carbon. Overtime, when its helium is depleted, the carbon it's transmuting will be used as fuel to create even heavier elements like neon, then oxygen, then silicon- until nothing is left but a heart of iron- the result of using silicon as star fuel. With each transition from one fuel source to the next, Rigel will bloat until it reaches an even more fantastic diameter. So, if there are planets circling nearby, they will most likely be engulfed! (Hopefully, Star Trek's Federation of Planets has contingency plans on file to evacuate all those colonists before they become toasted.)
When only iron remains to serve as a nuclear fuel source, Rigel, like other enormously massive stars, will put on one last, but a very dramatic, display. Since iron will not fuse into heavier materials, Rigel's core will collapse rapidly, either shrinking into a black hole- literally vanishing from sight- or exploding into a supernova becoming brighter than the combined light of the Milky Galaxy! Many astronomers believe the latter will be this star's fate and it's double star companion, located about fifty times farther than Pluto's orbit around our Sun, will most likely not escape unscathed, either!
Tracing Rigel's current position backwards, along the path that is it traveling through space, reveals that it was probably formed inside the Great Orion Nebula- one of the most spectacular stellar nurseries visible from Earth and easily seen without optical assistance from moderately light polluted skies. It appears as the middle fuzzy star in the sword hanging below Orion's belt. Rigel is still passing through a region of nebulosity. The gorgeous nebula that stimulated this discussion, and seen in the accompanying picture, is an example. It is illuminated by Rigel and about 100 light years behind it from our perspective. It's called the Witch Head nebula because many people see the silhouette of a hag's face.
The Witch Head is one of about 500 reflection nebulas that have been catalogued. Reflection nebulae tend to be some of the most beautiful objects in our Galaxy because they reflect the color of the stars that light them. Just as our skies appear blue because the oxygen and nitrogen molecules reflect the blue color component of sunlight, the microscopic dust particles in the Witch Head Nebula pass the red portions of the color spectrum and reflect the blue hues streaming from Rigel's brilliant nearby light. These particles are comprised principally of carbon and have been compared to diamond dust due to their reflective qualities and chemical makeup. Thus, this old gal may look like a witch, but she may also be worth a fortune!
This stunning picture was produced on September 23, 2006 by Richard Payne using a 6 inch telescope and an eleven mega-pixel astronomical camera. It represents a two-hour total exposure from his imaging location in Salome, AZ.
Do you have photos you'd like to share? Post them to the Universe Today astrophotography forum or email them, and we might feature one in Universe Today.
Written by R. Jay GaBany
Filed under: Astrophotos
January 31st, 2008 at 11:50 pm
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