仙后座的魅影

仙后座的魅影

Phantoms in Cassiopeia
Image Credit & Copyright: Christophe Vergnes, Hervé Laur

Explanation: These brightly outlined flowing shapes look ghostly on a cosmic scale. A telescopic view toward the constellation Cassiopeia, the colorful skyscape features the swept-back, comet-shaped clouds IC 59 (left) and IC 63. About 600 light-years distant, the clouds aren’t actually ghosts. They are slowly disappearing though, under the influence of energetic radiation from hot, luminous star gamma Cas. Gamma Cas is physically located only 3 to 4 light-years from the nebulae and lies just above the right edge of the frame. Slightly closer to gamma Cas, IC 63 is dominated by red H-alpha light emitted as hydrogen atoms ionized by the hot star’s ultraviolet radiation recombine with electrons. Farther from the star, IC 59 shows less H-alpha emission but more of the characteristic blue tint of dust reflected star light. The field of view spans over 1 degree or 10 light-years at the estimated distance of the interstellar apparitions.

Tomorrow’s picture: bats in space

仙后座的魅影
影像提供与版权: Christophe Vergnes, Hervé Laur

说明: 这些轮廓明亮带着流动形状的天体，形似宇宙级的幽灵。在这幅远眺仙后座的望远镜影像里，色彩缤纷星空的主角是向后拉伸、形如彗星的星云IC 59（左）和 IC 63。距离地球约600光年的这些星云，虽然并非真正的幽灵，但在炽热亮星“策”（Gamma Cas）高能星光的照射下，正在缓缓的消失之中。“策”位于视野的右上缘外头，离这些星云只有3至4光年远。距离“策”较近的IC 63，最主要的辐射，是氢原子受到这颗恒星的紫外光电离后，重新与电子复合时所发出的红光。而距离“策”稍远的IC 59，则发出较少量的氢α红光，但拥有较多因为尘埃反射星光的特征泛蓝辐射。这幅影像视野的跨度超过1度，以这些星际魅影所在的距离来换算，跨幅约为10光年。

明日的图片: bats in space