![\"\"](\"https:\/\/www.nasa.gov\/wp-content\/uploads\/2023\/10\/1-wise-lucy-dinkinesh.png?w=1500\")
<\/figure>Researchers have utilized infrared survey data to refine the asteroid\u2019s size and surface brightness in support of the Nov. 1 encounter by NASA\u2019s Lucy mission.<\/em><\/p>\n NASA\u2019s Lucy mission<\/a> will soon have its first asteroid encounter<\/a> as the spacecraft travels through deep space en route to Jupiter\u2019s orbit. But before the spacecraft passes 265 miles (425 kilometers) from the surface of the small asteroid Dinkinesh, researchers have used 13-year-old infrared data from NASA\u2019s Wide-field Infrared Survey Explorer (WISE<\/a>) to support the mission\u2019s flyby. Their new study provides updated estimates of the asteroid\u2019s size and albedo \u2013 a measurement of surface reflectivity \u2013 that could help scientists better understand the nature of some near-Earth objects.<\/p>\n Located between Mars and Jupiter, the main asteroid belt is home to most asteroids in our solar system, including Dinkinesh, which is following an orbit around the Sun that places it near Lucy\u2019s path. The Lucy mission is using the Dinkinesh encounter as an opportunity to test systems and procedures that are designed to keep the asteroid within the science instruments\u2019 fields of view as the spacecraft flies past at 10,000 mph (4.5 kilometers per second). This will help the team prepare for the mission\u2019s primary objective: investigating the Jupiter Trojan asteroids, a population of primitive small bodies orbiting in tandem with Jupiter.<\/p>\n In the new study<\/a>, published in the Astrophysical Journal Letters, University of Arizona researchers used observations made by the WISE spacecraft, which serendipitously scanned Dinkinesh in 2010 during its prime mission. Managed by NASA\u2019s Jet Propulsion Laboratory in Southern California, WISE launched on Dec. 14, 2009, to create an all-sky infrared map of the universe.<\/p>\n Although the signal was weak in the exposures captured by WISE, the authors managed to identify 17 infrared observations of the region of sky where Dinkinesh\u2019s signal could be seen. Then they used an algorithm to align and stack the images. The observations were made in March 2010 and represent 36.5 hours of observing time.<\/p>\n \u201cDinkinesh wasn\u2019t initially detected by WISE, because the asteroid\u2019s infrared signal was too weak for the software that was designed to find objects in a single exposure,\u201d said Kiana De\u2019Marius McFadden, a graduate student at the University of Arizona and lead author of the study. \u201cBut the asteroid\u2019s dim infrared signal was still there, so our main challenge was to first find Dinkinesh and then to stack multiple exposures of the same region of sky to get its signal to emerge from the noise.\u201d<\/p>\n Dinkinesh was discovered in 1999 \u2013 over a decade before WISE made the observations \u2013 and although its approximate size has been known, the new analysis refines not only its size, but also its albedo. The WISE observations suggest the asteroid has a diameter of about a half-mile (760 meters) and an albedo consistent with stony (S-type) asteroids.<\/p>\n Although WISE\u2019s purpose wasn\u2019t to detect asteroids, the spacecraft was sensitive to the infrared light (which is invisible to the naked eye) radiating from them as a result of sunlight heating their rocky surfaces. WISE had recorded about 190,000 asteroid observations by the end of its prime mission. In 2013, NASA reactivated WISE and renamed the mission Near-Earth Object Wide-field Survey Explorer (NEOWISE<\/a>). Its purpose: to detect and track asteroids and comets that stray close to Earth\u2019s orbit.<\/p>\n \u201cDinkinesh is the smallest main belt asteroid to be studied up-close and could provide valuable information about this type of object,\u201d said the University of Arizona\u2019s Amy Mainzer, a study co-author and the principal investigator for NEOWISE. \u201cThis population of main-belt asteroids overlap in size with the potentially hazardous near-Earth object population. Studying Dinkinesh could provide insights as to how these small main-belt asteroids form and where near-Earth asteroids come from.\u201d<\/p>\nBeyond WISE<\/strong><\/h2>\n