The constellation Orion and the winter Milky Way

AKARI’s Far Infrared Surveyor (FIS) instrument also observed the Milky Way and the Orion region. In this image, two views at visual light (left) and infrared light (right) are juxtaposed, both covering a region of about 30x40 square degrees. AKARI’s view is taken at 140 micrometres. For the first time ever, AKARI provided coverage of the Orion region at infrared wavelengths longer than 100 micrometres at such fine resolution.

The right side of the image covers the constellation Orion while the left side shows the Monoceros. The Galactic Plane is located from the top to bottom in the left side of the image. Cold dust in the Galactic Plane appears as diffuse radiation over the entire image.

The very bright source just below the belt of Orion shows the famous Orion Nebula (M42), where many stars are being born. Another major star-forming region including the Horse Head nebula can be seen on the left side of Orion's belt. In contrast to its appearance as a dark cloud in visible light, it is extremely bright in the infrared. The bright extended emission seen in the middle-left part of the image is the so-called Rosette Nebula, yet another star-forming region. Finally, the big circular structure centred at the head of Orion is clearly visible. Apparently many massive stars were formed at the centre of the circle, causing a corresponding series of supernova explosions that has swept out the dust and gas in the region forming a shell-like structure.

The Orion Nebula is located about 1500 light years away from Earth; the Rosetta nebula 3600 light years.

Star-forming region in the constellation Cygnus

This false-colour composite was obtained by AKARI’s Far Infrared Surveyor (FIS) instrument at 90 and 140 micrometres. It shows star-forming regions in the constellation Cygnus, one of the brightest regions in the Milky Way. The image covers 7.6 x 10.0 square degrees. This region is in a direction along the so-called ‘Orion arm’, one of the spiral arms of our Galaxy. Many objects at distances of three thousand to ten thousand light years are projected on this small region. The Galactic plane appears from the top-left to bottom-right.

The many bright spots in the image reveal regions where new stars are being born. They heat up the dust and ionize the gas in their vicinity producing strong infrared radiation. There are only a small number of regions in our Galaxy that exhibit so many massive star-forming regions over such a restricted area of the sky.

The large, dark hollows, also clearly visible on the image, developed from clusters of massive, high-temperature stars that have blown away the surrounding gas and dust by their strong radiation.

Note for editors

AKARI was launched on 21 February 2006. It began its all-sky survey observations in May 2006 and completed its first coverage of the sky in November 2006. The mission is currently in a phase dedicated to pointed observations, interleaved with supplemental scan observations to complete the all-sky survey. It is expected that the mission liquid Helium cryogen will last until at least September 2007.

AKARI is a JAXA mission carried out with the participation of several partners such as: the Nagoya University, The University of Tokyo and National Astronomical Observatory Japan; the European Space Agency (ESA); Imperial College London, the University of Sussex and The Open University (UK); the University of Groningen/SRON (The Netherlands); the Seoul National University (Korea). The far-infrared detectors were developed under collaboration with the National Institute of Information and Communications Technology (Japan).

ESA’s European Space Astronomy Centre (ESAC), Madrid, Spain provides expertise and support for the sky-survey data processing through the pointing reconstruction – this allows the determination of accurate astronomical positions for each of the sources detected. ESAC also provides user support for the European astronomers who have been granted observing opportunities. ESA’s Operations Centre (ESOC) in Darmstadt, Germany, is providing the mission with ground support through its ground station in Kiruna, for several passes per day.

For more information

Alberto Salama, ESA - ISO and AKARI Project Scientist
Email: alberto.salama @ esa.int