RCW 49

RCW 49 is a massive HII region at a distance of about 13,700 light-years, has a diameter of about 350 light years and is located in the constellation Carina. That stellar birthplace has a high dust content and contains more than 2,200 stars. Their central OB association NGC 3247 (also known as Westerlund 2).

In RCW 49 is a physical double star whose components orbit in about 3.7 days and have masses of about 82 and 83 Mʘ Mʘ. They represent one of the most massive stars known at all.