Surprise Image Of A Dying Star For WISE’s 4th Birthday
Brett Smith for redOrbit.com – Your Universe Online
To coincide with the fourth anniversary of NASA’s Wide-Field Infrared Survey Explorer (WISE) mission, the space agency has released an image showing a unique juxtaposition – a distant, dying star called the Helix nebula, surrounded by a halo of relatively close asteroids tracks.
The release of the image and the mission’s fourth anniversary comes after NASA brought WISE out of hibernation back in August to search for more asteroids.
“I was recently looking for asteroids in images collected in 2010, and this picture jumped out at me,” said Amy Mainzer, a principal investigator for the project at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “I recognized the Helix nebula right away.”
In the image, infrared wavelengths of light around the Helix nebula have been given different colors, with longer wavelengths being red and shorter wavelengths blue. A bluish-green outer ring and central red core depict the remnants of what was once a star similar to our own. As that star aged, it expanded and shed its outer layers. The burnt-out heart of the star, called a white dwarf, can now be seen heating the expelled material, causing it to glow with infrared light. Eventually, only the white dwarf will remain.
The brilliant display is encircled by a ring of streaking asteroids skirting around the edges of the nebula. Each streak represents a composited series of pictures of a singular asteroid. Scientists typically use these images to find and categorize asteroids. Infrared data captured by WISE is particularly useful for spotting smaller, darker asteroids that are difficult to see with visible light.
Launched on December 14, 2009 from Vandenberg Air Force Base in central California, WISE finished scanning the entire sky twice in infrared light by early 2011. During that time, the Earth-orbiting surveyor took pictures of almost one billion objects, including those of galaxies, stars and asteroids. After completing its initial mission, WISE was put into hibernation.
In November, NASA released a new and improved atlas and catalog of objects detected during two full scans of the sky. The purpose of each scan was different, so the images provided different information. NASA has funded a project called AllWISE to stack all the WISE images from both scans, which will double the exposure times and make new stars and galaxies visible.
“By stacking up the data, we have created a monster database with dozens of individual measurements on every one of the infrared sources we detect,” said Ned Wright of UCLA, the principal investigator of WISE.
NASA scientists expect the enhanced WISE images to also provide the ability to search for nearby stars, especially cooler ones that only show up in infrared light. The new atlas will allow astronomers to look at images of the sky taken six months apart; if something jumps across the images, then it must be located nearby and could be a never-before-seen neighbor.
Earlier this year, NASA engineers brought the infrared telescope out of its sleep. A loss of onboard coolant means that only two of its infrared channels can be used for asteroid hunting. The telescope is now tasked with finding objects that have the potential to strike Earth.