BY KEITH COOPER
Posted: 20 April, 2009
The Great Nebula of Orion, M42, has been revealed to be a madhouse, containing hundreds of very young stars in close proximity, with powerful jets emanating from their poles and racing away at tens or even hundreds of kilometres per second.
The research is being presented today at the RAS' National Astronomy Meeting at the European Week of Astronomy and Space Science held at the University of Hertfordshire. A triumvirate of observatories including NASA's infrared-seeing Spitzer Space Telescope, the United Kingdom Infrared Telescope (UKIRT) in Hawaii and the IRAM millimetre-wave telescope in Spain supplied the vital data for the project, which was the brainchild of Dr Chris Davis.
Based at the Joint Astronomy Centre in Hawaii, and spurred on by mid-infrared images of M42 taken by UKIRT, Davis proceeded to contact colleagues at the other observatories to collate as much data as possible. From IRAM came detailed maps of molecular dust and gas in the vast Orion Molecular Cloud (OMC) that rings the eponymous constellation, and which M42 is only a tiny part of. Meanwhile, recent catalogues of young stars in the OMC came from Spitzer, which can see through the thick veils of gas and dust. Comparing all this data with archival images from the Calar Alto Observatory in Spain, Davis was able to measure the speed and direction of 110 jets blasting out from young stars, and even pinpoint the exact stars that these jets are emanating from.
Young protostars produce powerful jets of hydrogen molecules simply because they are taking on more material from the surrounding nebula and protoplanetary disc than they can swallow. Such accretion is the nourishment that helps young stars grow. The waste material is spewed out in giant jets, which over time will fizzle out as the amount of raw gas in the vicinity dries up.
"Regions like this are usually referred to as stellar nurseries, but we have shown that this one is not being well run," says Davis. "It is chaotic and overcrowded."