ESO Press Photos 03a-d/01 17 January 2001 For immediate release

The Orion Nebula: The Jewel in the Sword

Major VLT Research Project Opens with Beautiful Infrared View

ESO PR Photo 03a/01 [Preview - JPEG: 400 x 493 pix - 68k] [Normal - JPEG: 800 x 985 pix - 528k] [Hires - JPEG: 2758 x 3405 pix - 4.5M]

Caption: PR Photo 03a/01 is a colour composite mosaic image of the central part of the Orion Nebula, based on 81 images obtained with the infrared multi-mode ISAAC instrument on the ESO Very Large Telescope (VLT) at the Paranal Observatory. The famous Trapezium stars are seen near the centre and the photo also shows the associated cluster of about one thousand stars, about a million years old. Technical information about this photo is available below.

Orion the Hunter is perhaps the best known constellation in the sky, well placed in the evening at this time of the year for observers in both the northern and southern hemispheres, and instantly recognisable. And for astronomers, Orion is surely one of the most important constellations, as it contains one of the nearest and most active stellar nurseries in the Milky Way, the galaxy in which we live.

Here tens of thousands of new stars have formed within the past ten million years or so - a very short span of time in astronomical terms. For comparison: our own Sun is now 4,600 million years old and has not yet reached half-age. Reduced to a human time-scale, star formation in Orion would have been going on for just one month as compared to the Sun's 40 years.

Just below Orion's belt, the hilt of his sword holds a great jewel in the sky, the beautiful Orion Nebula. Bright enough to be seen with the naked eye, a small telescope or even binoculars show the nebula to be a few tens of light-years' wide complex of gas and dust, illuminated by several massive and hot stars at its core, the famous Trapezium stars.

However, the heart of this nebula also conceals a secret from the casual observer. There are in fact about one thousand very young stars about one million years old within the so-called Trapezium Cluster, crowded into a space less than the distance between the Sun and its nearest neighbour stars. The cluster is very hard to observe in visible light, but is clearly seen in the above spectacular image of this area (ESO PR 03a/01), obtained in December 1999 by Mark McCaughrean (Astrophysical Institute Potsdam, Germany) and his collaborators [1] with the infrared multi-mode ISAAC instrument on the ESO Very Large Telescope (VLT) at Paranal (Chile).