Like most other supergiant stars, Alnilam is losing mass at a very high rate. Alnilam is located at around 1,975 light-years / 600 parsecs away from the Sun.Some estimates put it even farther or closer. It is the biggest star in Orion’s Belt. Studies have shown that the star’s 2,000 km/sec solar wind is blasting material away from it at the rate of two millionths of a solar mass every year, which in absolute terms, translates into a mass loss of about 20 million times that at which the Sun is losing its mass. Estimates of Alnilam's properties vary. Alnilam . Alnilam is also more than 30 times bigger than our sun. Searle and colleagues, using CMFGEN code to analyse the spectrum in 2008, calculated a luminosity of 537,000 L☉, an effective temperature of 27,500 ± 100 K and a radius of 32.4 ± 0.75 R☉. Alnilam is also the most massive star in Orion’s Belt. Crowther and colleagues, using stellar wind and atmospheric modelling in 2006, came up with a luminosity 275,000 times that of the Sun (L☉), and effective temperature of 27,000 K and a radius 24 times that of the Sun (R☉). It has 40 times the mass of our Sun. Alnilam or Epsilon Orionis (Eps Ori) is the 4th brightest naked eye star in the constellation The image above shows the uncropped view of Alnilam (North is up) through the Alnilam is a large blue-white supergiant (spectral type B0 Iab) and is the most powerful bright star in the sky. Alnilam or Epsilon Orionis (Eps Ori) is the 4th brightest naked eye star in the constellation Orion.With an apparent magnitude of 1.69v, Alnilam is the 29th brightest star in the entire sky (see: 50 Brightest Stars ).Its absolute magnitude is -6.38 and its distance is 1342 light years.The Equinox J2000 equatorial coordinates are RA = 05h 36m 12.8s, Dec = -01° 12' 07". Analysis of the spectra and age of the m… Alnilam’s radius has been estimated to be around 32.4 times that of the sun.