Astronomy Picture of the Day—20190224

Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.

2019 February 24

Jupiterin Ultraviolet from Hubble

ImageCredit: NASA, ESA, Hubble; Processing & License: Judy Schmidt

Explanation:Jupiter looks a bit different in ultraviolet light. To better interpretJupiter's cloud motions and to help NASA's robotic Juno spacecraft understandthe planetary context of the small fields that it sees, the Hubble SpaceTelescope is being directed to regularly image the entire Jovian giant. Thecolors of Jupiter being monitored go beyond the normal human visual range toinclude both ultraviolet and (not pictured) infrared light. Featured from 2017,Jupiter appears different in near ultraviolet light, partly because the amountof sunlight reflected back is distinct, giving differing cloud heights andlatitudes discrepant brightnesses. In the near UV, Jupiter's poles appearrelatively dark, as does its Great Red Spot and a smaller (optically) whiteoval to the right. The String of Pearl storms farther to the right, however,are brightest in near ultraviolet, and so here appear (false-color) pink.Jupiter's largest moon Ganymede appears on the upper left. Juno continues onits looping 53-day orbits around Jupiter, while Earth-orbiting Hubble is nowrecovering from the loss of a stabilizing gyroscope.

哈勃在紫外波段拍摄的木星

解释：木星在紫外波段看上去有一点不同。为了更好地阐释木星的云层运动，帮助美国宇航局的朱诺飞船了解它看到的小视场的行星背景，哈勃空间望远镜被指令定期地拍摄整颗木星。被监测的木星的颜色超越通常人类的视觉范围，包括紫外波段和红外波段（未拍摄）。2017年，木星在近紫外波段呈现不同的外貌，部分因为被反射回来的阳光的数量是不同的，给定不同的云层高度和纬度和差异性亮度。在近紫外波段，木星的两极显得相对地黑暗，它的大红斑及其右侧的较小的白椭圆也是这样。然而，最右面的“珠链”风暴在近紫外波段最亮，因此，这里呈现为粉红色（伪彩色）。木星最大的卫星木卫三出现在左上方。朱诺继续它绕木星的53天环形轨道，而绕地球转动的哈勃现在失去了稳定陀螺仪，正处于恢复过程中。