jeudi 15 janvier 2015

NEOWISE: A Yearlong Look at the Sky

NASA - NEO WISE Mission logo.

January 15, 2015

NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE) spacecraft discovered and characterized 40 near-Earth objects (NEOs) in the first year after the mission was re-started in December 2013. Eight of the discoveries have been classified as potentially hazardous asteroids (PHAs), based on their size and how close their orbits could come to Earth's orbit.

video
One Year of NEOWISE Observations Mapped

Video above: This movie shows the progression of NASA's NEOWISE survey in the year after its Dec. 2013 restart.

The mission has further observed and characterized 245 previously known near-Earth objects. From December 2013 to December 2014, NEOWISE discovered three new comets and observed 32 others. One of the others has turned into the brightest comet in Earth's night sky in early 2015, comet C/2014 Q2 (Lovejoy).

NEOWISE always looks in the dawn and twilight skies – the direction perpendicular to a line between Earth and the sun. This unique vantage point makes it easy for NEOWISE to spot NEOs that get particularly close to Earth.


Image above: Comet C/2014 Q2 (Lovejoy) is one of more than 32 comets imaged by NASA's NEOWISE mission from December 2013 to December 2014. This image of comet Lovejoy combines a series of observations made in November 2013. Image Credit: NASA/JPL-Caltech.

Originally called the Wide-field Infrared Survey Explorer (WISE), the spacecraft was placed in hibernation in 2011 after its primary mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission to assist NASA's efforts to identify the population of potentially hazardous near-Earth objects. NEOWISE is also characterizing previously known asteroids and comets to provide information about their sizes and compositions.

NEOWISE is a space telescope that scans the skies for asteroids and comets. The telescope sees infrared light, which allows it to pick up the heat signature of asteroids and obtain better estimates of their true sizes. As a result, NEOWISE can see dark asteroids that are harder for visible-light surveys to find. Nearly all of the NEOWISE discoveries have been large (hundreds of yards, or meters, wide) and very dark, similar to printer toner. When NEOWISE's infrared data on an object is combined with that of a visible-light optical telescope, it helps scientists understand the object's composition.


Image above: On clear nights in January 2015, comet C/2014 Q2 (Lovejoy) is visible in the Taurus region of the sky to observers using binoculars. This chart indicates where to look for it on different dates during the month. Image Credit: NASA/JPL-Caltech.

NASA's Jet Propulsion Laboratory in Pasadena, California, manages the NEOWISE mission for NASA's Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA. For more information about NEOWISE, visit: http://www.nasa.gov/neowise

More information about asteroids and near-Earth objects is at: http://www.jpl.nasa.gov/asteroidwatch

Images (mentioned), Video, Text, Credits: NASA/Dwayne Brown/JPL/DC Agle.

Greetings, Orbiter.ch

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