蛋星云的偏振光影像

2023年4月9日

The Egg Nebula in Polarized Light
Image Credit: Hubble Heritage Team (STScI / AURA), W. Sparks (STScI) & R. Sahai (JPL), NASA

Explanation: Where is the center of the Egg Nebula? Emerging from a cosmic egg, the star in the center of the Egg Nebula is casting away shells of gas and dust as it slowly transforms itself into a white dwarf star. The Egg Nebula is a rapidly evolving pre- planetary nebula spanning about one light year. It lies some 3,000 light-years away toward the northern constellation Cygnus. Thick dust blocks the center star from view, while the dust shells farther out reflect light from this star. Light vibrating in the plane defined by each dust grain, the central star, and the observer is preferentially reflected, causing an effect known as polarization. Measuring the orientation of the polarized light for the Egg Nebula gives clues to location of the hidden source. Taken by Hubble’s Advanced Camera for Surveys in 2002, this image is rendered in artifical “Easter-Egg” colors coded to highlight the orientation of polarization.

Tomorrow’s picture: big chicken

蛋星云的偏振光影像
影像提供: Hubble Heritage Team (STScI / AURA), W. Sparks (STScI) & R. Sahai (JPL), NASA

说明: 蛋星云的中心何在？位于蛋星云中心的恒星，正在抛出外层的气体和尘埃，慢慢变身为白矮星。蛋星云位在北天的天鹅座方向，离我们约3,000光年远，宽度约为1光年，是一团快速演化即将成为行星状星云的”前导星云“。由于受到厚重尘埃的遮掩，我们其实看不到这颗中心星，不过外围的尘埃壳则因为反射这颗恒星的星光而现身。此外，振动方向在尘埃微粒、中心星和观测者所定出的平面之星光，会被大幅反射，造成星光的偏振效应。所以只要量测来自蛋星云的偏振光方向，就能取得这颗隐不见恒星的位置线索。这幅由哈勃太空望远镜先进巡天相机在2002年拍摄的影像，使用“复活节彩蛋”的颜色加以处理，以突显所测得的光偏振方向。 （Egg Nebula 蛋星云）

明日的图片: big chicken