Alnilam is the central star of Orion's Belt in the equatorial constellation of Orion. It has the Bayer designation ε Orionis, which is Latinised to Epsilon Orionis and abbreviated Epsilon Ori or ε Ori. This is a massive, blue supergiant star some 1,200 light-years distant.

参宿二（ε Ori / 猎户座ε），是全夜空第30亮的恒星，位于猎户座。西方则称之为Alnilam，在佛兰斯蒂德命名法中则称为猎户座46，距离地球约1980光年（606秒差距）。参宿二在猎户座中则名列第4位，是一颗B0Ia 蓝超巨星，也是已知最明亮的恒星之一。

2024年12月11日 · Alnilam is the central star of Orion’s Belt, an asterism known since ancient times. Orion’s Belt is also formed by the bright stars Alnitak (Zeta Orionis) and Mintaka (Delta Orionis). Alnilam is the only single star of the three, as well as the brightest.

參 （ shēn ） 宿 （ xiù ） 二（ε Ori / 獵戶座ε）位於獵戶座，西方則稱之為Alnilam，在佛蘭斯蒂德命名法中則稱為獵戶座46。 參宿二 是全夜空第30亮的恆星，在獵戶座中則名列第4位，是一顆B0Ia 藍超巨星 ，也是已知最明亮的恆星之一。

2021年3月9日 · Alnilam is the middle star in the famous three-member belt of Orion, the Hunter. The belt is so easily recognizable because all three stars are spaced evenly in a (roughly) straight line and appear to be about the same brightness. But Alnilam stands out for being super massive, super distant, and, perhaps most intriguingly, super luminous.

2020年1月30日 · Alnilam is around 537.000 times brighter than our Sun, it is the brightest star of Orion’s Belt. Because of this brightness, it illuminates a molecular cloud, NGC 1990, that appears to have surrounded the star.

2024年2月9日 · 位于三星中间的，就是参宿二，猎户座ε，英文名Alnilam，目视星等为1.64等，也是全天排名第29位的亮星，距离我们1980光年，它也是三星中距离我们最远的一颗。

Epsilon (ε) Orion, Alnilam, is a brilliant white star occupying the central position in Orion‘s belt. Alnilam, Anilam, Ainilam, and Alnihan are from Al Nitham, or Al Nathm, the String of Pearls, or, as British physicist Robert Recorde (1500-1558) said, the Bullions set in the middle of Orion’s Belt.

Alnilam, the blue supergiant star, has a variable brightness that ranks it as the 29th most luminousstar of all the known stars viewed from Earth. Its luminosity is the amount of energy emission from this giant star relative to the Sun.

Alnilam, also designated as ε Orionis (epsilon Orionis), is a variable and double hypergiant star of spectral class B0 in the constellation of Orion. Alnilam visual magnitude is 1.7, making it the 28th brightest star in the sky.