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Tens of thousands of asteroids and 20 new comets are the result of the recently completed NEOWISE mission, that has spent 4 months searching for minor bodies in our solar system.
When, at the start of October last year, the Wide-field Infrared Survey Explorer exhausted its supply of liquid coolant, necessary for its two far-infrared sensors, NASA decided to continue the mission for a further 4 months, using the other two infrared detectors to complete a survey of the main asteroid belt and search for new comets. From that point the WISE mission became NEOWISE.
In just one year of activity WISE mapped the entire sky 1.5 times, taking 2.7 million images, and detecting 153 thousand of the 500 thousand known asteroids, itself discovering 33 thousand new bodies. Of these, 134 are Near-Earth Objects (so potentially dangerous), a significant fraction of the 2000 known.
Over 100 comets have been observed, with the 20 new discoveries pictured in the mosaic above. Four of the new comets are particularly interesting because they had previously been classified as asteroids, likely because, at the epoch of observation, they were inactive due to their proximity to aphelion. One of these, the top left in the image, called 237P/LINEAR (2002 LN13) had been classified as an asteroid since 2002.
The publication of the scientific results of WISE and NEOWISE are eagerly anticipated, especially because the instruments onboard were capable of detecting brown dwarfs and gas giant planets very far from the Sun. If our Solar system has other giant planets at very great distances from the Sun, or even a neighbouring brown dwarf, then this mission could have detected them.
Next April the first set of WISE observations will be made available to the scientific community and general public, so that anyone will be able to search the enormous quantity of data for new celestial bodies.
NEOWISE will now be put into hibernation in polar Earth orbit, but it will remain possible to reactivate the satellite if the need arises.
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