NASA releases a new infrared sky map

Mosaic of sky images as observed by the Wide-field Infrared Survey Explorer (WISE) (Image NASA/JPL-Caltech/UCLA)
Mosaic of sky images as observed by the Wide-field Infrared Survey Explorer (WISE) (Image NASA/JPL-Caltech/UCLA)

NASA unveiled a catalog of the sky observed by the Infrared Space Telescope Wide-field Infrared Survey Explorer (WISE).

The WISE mission started on December 14, 2009 with the launch of the Space Telescope using a Delta II rocket. The WISE regularly entered in a polar orbit at about 525 km (325 miles) of altitude and began its observations of the sky with its 40 cm (16 inches) diameter infrared telescope. This instrument was built to obtain images a thousand times more sensitive than the similar telescopes previously used.

The WISE telescope went on for ten months with its mission, then extended for another four months in a survey focused on asteroids and comets called Near-Earth Object WISE (NEOWISE). WISE recorded a total of about two million seven hundred thousand images at four different wavelengths belonging to the infrared spectrum. The different wavelengths were used to have a sensitivity to the emissions of different celestial bodies ranging from small asteroids to enormous galaxies.

The WISE telescope observations uncovered many brown dwarfs of class Y. Brown dwarfs are essentially failed stars, objects with insufficient mass to sustain nuclear reactions which however radiate energy because of their contraction, following the Kelvin-Helmholtz mechanism. Class Y brown dwarfs are the coldest of all, therefore they radiate energy in the infrared spectrum and only thanks to the WISE telescope it’s been possible to locate them.

Other discoveries made by the WISE telescope were unexpected. For example, a trojan asteroid that shares the same orbit of Earth around the Sun.

Another image that raised a lot of interest is the one of an infrared light echo around a supergiant star died about eleven thousands years ago, when it exploded in a supernova.

The WISE telescope has allowed us to classify more than half a billion stars, galaxies and other objects. Scientists have already started to study the images obtained some time ago and they have enough material to keep them busy for a long time. As always in these cases, the mission of a space probe ends but scientific research can go on for many years thanks to the huge amount of data obtained.

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