A new image from NASA's Spitzer and Hubble Space Telescopes looks more like an abstract painting than a cosmic snapshot. The masterpiece shows the Orion nebula in an explosion of infrared, ultraviolet, and visible-light colours. It was "painted" by hundreds of baby stars on a canvas of gas and dust, with intense ultraviolet light and strong stellar winds as brushes. At the heart of the artwork is a set of four monstrously massive stars, collectively called the Trapezium. These behemoths are approximately 100,000 times brighter than our sun. Their community can be identified as the yellow smudge near the centre of the composite. The swirls of green were revealed by Hubble's ultraviolet and visible-light detectors. They are hydrogen and sulphur gases heated by intense ultraviolet radiation from the Trapezium's stars. Wisps of red and orange detected by Spitzer indicate infrared light from illuminated clouds containing carbon-rich molecules called polycyclic aromatic hydrocarbons. On Earth, polycyclic aromatic hydrocarbons are found on burnt toast and in automobile exhaust.
Expand (136kb, 720 x 900) Credit: NASA/JPL-Caltech/T. Megeath (University of Toledo) & M. Robberto (STScI)
Astronomers have long scrutinized the vast and layered clouds of the Orion nebula, an industrious star-making factory visible to the naked eye in the sword of the famous hunter constellation. Yet, Orion is still full of secrets.
A new image from NASA's Spitzer Space Telescope probes deep into the clouds of dust that permeate the nebula and its surrounding regions. The striking false-colour picture shows pinkish swirls of dust speckled with stars, some of which are orbited by disks of planet-forming dust. Spitzer, with its powerful infrared vision, was able to unearth nearly 2,300 such planet-forming disks in the Orion cloud complex, a collection of turbulent star-forming clouds that includes the well-known Orion nebula. The disks -- made of gas and dust that whirl around young suns -- are too small and distant to be seen by visible-light telescopes; however, the infrared glow of their warm dust is easily spotted by Spitzer's infrared detectors. Each disk has the potential to form planets and its own solar system.
Expand (88kb, 720x900) Position (2000): RA: 5h35m14.1s Dec: -05d22m23s
"This is the most complete census of young stars with disks in the Orion cloud complex. Basically, we have a census of potential solar systems, and we want to know how many are born in the cities, how many in small towns, and how many out in the countryside" - Dr. Thomas Megeath of the University of Toledo, Ohio, who led the research.
A look at Orion's demographics reveals that the potential solar systems populate a variety of environments. Megeath and his colleagues found that about 60 percent of the disk-sporting stars in the Orion cloud complex inhabit its bustling "cities," or clusters, containing hundreds of young stars. About 15 percent reside in small outer communities, and a surprising 25 percent prefer to go it alone, living in isolation. Prior to the Spitzer observations, scientists thought that up to 90 percent of young stars, both with and without disks, dwelled in cities like those of Orion.
The Great Nebula in Orion is an immense nearby starbirth region. Glowing gas surrounds hot young stars at the edge of an immense interstellar molecular cloud only 1500 light-years away. In the image, faint wisps and sheets of dust and gas are particularly evident.
The Great Nebula in Orion can be found with the unaided eye just below and to the left of the easily identifiable belt of three stars in the popular constellation Orion. In addition to housing a bright open cluster of stars known as the Trapezium, the Orion Nebula contains many stellar nurseries. These nurseries contain hydrogen gas, hot young stars, proplyds, and stellar jets spewing material at high speeds. Also known as M42, the Orion Nebula spans about 40 light years and is located in the same spiral arm of our Galaxy as the Sun.