Astronomy Picture of the Day

Explanation: Antares is a huge star. In a class called red supergiant, Antares is about 700 times the size of our own Sun, 15 times more massive, and 10,000 times brighter. Antares is the brightest star in the constellation of Scorpius and one of the brighter stars in all the night sky. Antares is seen surrounded by a nebula of gas which it has itself expelled. Radiation from Antares' blue stellar companion helps cause the nebular gas to glow, as photographed above. Antares is located about 500 light years away.

心宿二是顆龐大的恒星。 分類為紅超巨星的心宿二，半徑是我們太陽的700倍，質量為15倍，而亮度則是10,000倍。 心宿二是天蠍座的最亮星，也是地球夜空中最明亮的恒星之一。 人們所見的心宿二，其實包裹在它自己排出的雲氣裡。 而來自心宿二泛藍伴星的輻射，則激發這些雲氣發出輝光，就如上圖所示。 心宿二離我們約500光年遠。