Veil Nebula 2-pane mosaic from Negev desert. During the last month two clear nights allowed me to collect data of this object.

The Veil nebula is the expanding remains of a star that exploded between 5,000 and 10,000 years ago in our Milky Way galaxy.
The entire nebula is 110 light-years across, covering six full moons on the sky as seen from Earth, and resides about 2,100 light-years away in the constellation Cygnus the Swan.

Colorful smoke-like wisps of gas are all that remain visible of what was once a star some 20 times more massive than our sun. Prior to the explosion, a strong stellar wind (a stream of charged particles) from this star blew a large cavity or bubble in the surrounding area. The intertwined wisps of gas in the Veil Nebula result from the energy released as the fast-moving shock wave, or blast wave, from the ancient explosion plows into the edges or walls of this cavity. The blast wave initially heated the material to millions of degrees, but as the gas cools down again, it produces the brilliant glowing colors.

The nebula’s colors correspond to variations in the temperature and density of the glowing interstellar material. Blue, for example, arises in hotter gas that has more recently encountered the shock wave. Most of the red material denote cooler gas that collided with the blast wave even longer ago. Although the supernova explosion occurred thousands of years ago, the speedy shock wave is still moving at 1.4 million miles per hour (2.3 million kilometers per hour). The shock wave is moving so fast that it could travel from Earth to the Moon in 15 minutes. It takes years, however, before this motion is even slightly visible to telescopes because the nebula is so far away.

The Pickering's Triangle area of the Veil Nebula was discovered photographically in 1904 by Williamina Fleming, but credit went to Edward Charles Pickering, the director of her observatory, as was the custom of the day.

Image credits and copyright: Leo Shatz
Text credits: NASA