Astronomy Picture of the Day—三角座星系

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 March 10

TheStars of the Triangulum Galaxy

ImageCredit: NASA, ESA, M. Durbin, J. Dalcanton, and B. F. Williams (University ofWashington)

Explanation:Like grains of sand on a cosmic beach, stars of the Triangulum Galaxy areresolved in this sharp mosaic from the Hubble Space Telescope's Advanced Camerafor Surveys (ACS). The inner region of the galaxy spanning over 17,000light-years is covered at extreme resolution, the second largest image everreleased by Hubble. At its center is the bright, densely packed galactic coresurrounded by a loose array of dark dust lanes mixed with the stars in thegalactic plane. Also known as M33, the face-on spiral galaxy lies 3 millionlight-years away in the small northern constellation Triangulum. Over 50,000light-years in diameter, the Triangulum Galaxy is the third largest in theLocal Group of galaxies after the Andromeda Galaxy (M31), and our own MilkyWay. Of course, to fully appreciate the Triangulum's stars, star clusters, andbright nebulae captured in this Hubble mosaic, you'll need to use a zoom tool.

三角座星系

解释：在哈勃空间望远镜的先进巡天相机（ACS）拍摄的这幅清晰拼接影像中，三角座星系的恒星和宇宙海滩上的沙砾一样清晰可辨。三角座星系的内区覆盖超过17000光年，以极高的分辨率被覆盖，是哈勃迄今释放的第二大影像。它的中心是明亮而致密的星系核。又被称为M33，这个正对我们的旋涡星系距离300万光年，位于小小的三角座中。直径超过5万光年，三角座星系是本星系群中第三大的星系，排在仙女座星系和银河系之后。