Sky's Up Global Astronomy Magazine Volume IV (December 2021) | Page 10

wonderful universe

June 8 , 2021

Juno nabs a close-up of Jovian moon Ganymede

This image of the Jovian moon Ganymede was obtained by the JunoCam imager aboard NASA ’ s Juno spacecraft during its June 7 , 2021 , flyby of the icy moon . At the time of closest approach , Juno was within 645 miles ( 1,038 kilometers ) of its surface – closer to Jupiter ’ s largest moon than any other spacecraft has come in more than two decades . This image is a preliminary product – Ganymede as seen through JunoCam ’ s green filter . Juno is a spin-stabilized spacecraft ( with a rotation rate of 2 rpm ), and the JunoCam imager has a fixed field of view . To obtain Ganymede images as Juno rotated , the camera acquired a strip at a time as the target passed through its field of view . These image strips were captured separately through the red , green , and blue filters . To generate the final image product , the strips must be stitched together , and colors aligned . At the time this preliminary image was generated , the “ spice kernels ” ( navigation and other ancillary information providing precision observation geometry ) necessary to properly map-project the imagery were not available . The red , and blue filtered image strips were also not available . When the final spice kernel data and images from the two filters are incorporated , the images seams ( most prevalent on lower right of sphere ) will disappear , and a complete color image will be generated .

SOURCE : nasa . gov / image-feature / jpl / juno-s-ganymede-close-up • IMAGE CREDIT : NASA

July 22 , 2021

The PDS 70 system as seen through the eyes of ALMA

This image , taken with the Atacama Large Millimeter / submillimeter Array ( ALMA ), in which ESO is a partner , shows the PDS 70 system , located nearly 400 light-years away and still in the process of being formed . The system features a star at its center and at least two planets orbiting it , PDS 70b ( not visible in the image ) and PDS 70c , surrounded by a circumplanetary disc ( the

SOURCE : eso . org / public / news / eso2111 / • IMAGE CREDIT : ALMA ( ESO / NAOJ / NRAO )/ Benisty et al .

dot to the right of the star ). The planets have carved a cavity in the circumstellar disc ( the ring-like structure that dominates the image ) as they gobbled up material from the disc itself , growing in size . It was during this process that PDS 70c acquired its own circumplanetary disc , which contributes to the growth of the planet and where moons can form .

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