Nebulas and Massive Stars

Astronomy Picture of the Day

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2010 November 21
A Massive Star in NGC 6357 
Credit: NASA, ESA and J. M. Apellániz (IAA, Spain)Explanation: For reasons unknown, NGC 6357 is forming some of the most massive stars ever discovered. One such massive star, near the center of NGC 6357, is framed above carving out its own interstellar castle with its energetic light from surrounding gas and dust. In the greater nebula, the intricate patterns are caused by complex interactions between interstellar winds, radiation pressures, magnetic fields, and gravity. The overall glow of the nebula results from the emission of light from ionized hydrogen gas. Near the more obvious Cat's Paw nebula, NGC 6357 houses the open star cluster Pismis 24, home to many of these tremendously bright and blue stars. The central part of NGC 6357 shown spans about 10 light years and lies about 8,000 light years away toward the constellation of the Scorpion.

Image of the Day: The Ghoulish Beauty of the Cone Nebula

The Cone Nebula, part of a much larger star-forming complex, is at bottom with inverted Christmas Tree cluster NGC 2264 above the cone; the bright star just above the cone is the tree topper and the very bright star at the top of the image is the center of the tree trunk. The Fox Fur Nebula is at the top right corner.

The Snowflake nebula is in the middle which shows up better on the infrared image. The cone's shape comes from a dark absorption nebula consisting of cold molecular hydrogen and dust in front of a faint emission nebula containing hydrogen ionized by S Monocerotis, the brightest star of NGC 2264. The faint nebula is approximately seven light-years long, and is 2,700 light-years away from Earth.

Credit: ESO