Westerlund 2とは 意味・読み方・使い方

Westerlund 2 is a young massive obscured star cluster with an estimated age of about one or two million years. It contains some of the hottest, brightest, and most massive stars known. The cluster contains a dozen of O stars, of which at least three are eclipsing binaries, many pre–main sequence stars and two Wolf-Rayet Stars: the binary WR20a and the single star WR20b, all of spectral type WN6ha. They are probably not actually Wolf-Rayet stars, i.e. they are core hydrogen burning stars, just like the sun. Due to their large mass loss rate they appear to be Wolf Rayet stars.