Comet C/2018 Y1 Iwamoto as imaged in multiple exposures of infrared light by the NEOWISE space telescope. The infrared images were taken on Feb. 25, 2019, when the comet was about 56 million miles, or 90 million kilometers, from Earth.
C/2018 Y1 Iwamoto is a long-period comet originally from the Oort Cloud and coming in near the Sun for the first time in over 1,000 years.
Appearing as a string of red dots, this comet can be seen in a series of exposures captured by the spacecraft. Infrared light detected by the 3.4-micron channel is mapped to blue and green, while light from the 4.6-micron channel is mapped to red. In this image, stars show up as blue because they are hotter, whereas the cooler dust around the comet - with a temperature near the freezing point of water - glows red.