From ESA: “Star formation and magnetic turbulence in the Orion Molecular Cloud”

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European Space Agency

18/05/2015
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ESA and the Planck Collaboration

With blue hues suggestive of marine paradises and a texture evoking the tranquil flow of sea waves, this image might make us daydream of sandy beaches and exotic holiday destinations. Instead, the subject of the scene is intense and powerful, because it depicts the formation of stars in the turbulent billows of gas and dust of the Orion Molecular Cloud.

The image is based on data from ESA’s Planck satellite, which scanned the sky between 2009 and 2013 to study the cosmic microwave background [CMB], the most ancient light in the Universe’s history.

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Planck

Cosmic Microwave Background  Planck
CMB per Planck

While doing so, Planck also detected foreground emission from material in the Milky Way, as well as from other galaxies.

Our Galaxy is pervaded by a diffuse mixture of gas and dust that occasionally becomes denser, creating giant gas clouds where stars can form. While present only in traces, dust is a crucial ingredient in these interstellar clouds. It also shines brightly at some of the wavelengths that were probed by Planck, so astronomers can use these data to learn more about the cradles of star formation.

In addition, dust grains have elongated shapes and tend to align their longest axis at right angles to the direction of the Galaxy’s magnetic field. This makes their emission partly ‘polarised’ – it vibrates in a preferred direction. Since Planck was equipped with polarisation-sensitive detectors, its scans also contain information about the direction of the magnetic field threading the Milky Way.

This image combines a visualisation of the total intensity of dust emission, shown in the colour scale, with an indication of the magnetic field’s orientation, represented by the texture. Blue hues correspond to regions with little dust, while the yellow and red areas reflect denser (and mostly hotter) clouds containing larger amounts of dust, as well as gas.

The red clumps at the centre of the image are part of the Orion Molecular Cloud Complex, one of the closest large regions of star formation, only about 1300 light-years from the Sun.

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Part of the Orion Molecular Cloud Complex, with the Great Nebula in Orion near the center, along with the Belt of Orion, and Barnard’s Loop curling around the image

The most prominent of the red clumps, to the lower left of centre, is the famous Orion Nebula, also known as M42.

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In one of the most detailed astronomical images ever produced, NASA/ESA’s Hubble Space Telescope captured an unprecedented look at the Orion Nebula. … This extensive study took 105 Hubble orbits to complete. All imaging instruments aboard the telescope were used simultaneously to study Orion. The Advanced Camera mosaic covers approximately the apparent angular size of the full moon.

This is visible to the naked eye in the constellation Orion, just below the three stars forming the ‘belt’ of the mythological hunter. An annotated version of the image can be found here.

The magnetic field appears regular and organised in almost parallel lines in the upper part of the image: this is a result of the large-scale arrangement of the magnetic field along the Galactic plane, which is located above the top of this image. However, the field becomes less regular in the central and lower parts of the image, in the region of the Orion Molecular Cloud. Astronomers believe that the turbulent structure of the magnetic field observed in this and other star-forming clouds is related to the powerful processes taking place when stars are being born.

The emission from dust is computed from a combination of Planck observations at 353, 545 and 857 GHz, whereas the direction of the magnetic field is based on Planck polarisation data at 353 GHz. The image spans about 40º across.

See the full article here.

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The European Space Agency (ESA), established in 1975, is an intergovernmental organization dedicated to the exploration of space, currently with 19 member states. Headquartered in Paris, ESA has a staff of more than 2,000. ESA’s space flight program includes human spaceflight, mainly through the participation in the International Space Station program, the launch and operations of unmanned exploration missions to other planets and the Moon, Earth observation, science, telecommunication as well as maintaining a major spaceport, the Guiana Space Centre at Kourou, French Guiana, and designing launch vehicles. ESA science missions are based at ESTEC in Noordwijk, Netherlands, Earth Observation missions at ESRIN in Frascati, Italy, ESA Mission Control (ESOC) is in Darmstadt, Germany, the European Astronaut Centre (EAC) that trains astronauts for future missions is situated in Cologne, Germany, and the European Space Astronomy Centre is located in Villanueva de la Cañada, Spain.

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