sentences:  Westerlund 1
  
  Westerlund 1 (abbreviated Wd1, sometimes called Ara Cluster) is a compact young super star cluster in the Milky Way galaxy, about 3.2 kpc away from Earth.It is one of the most massive young star clusters in the Milky Way, and was discovered by Bengt Westerlund in 1961 but remained largely unstudied for many years due to high interstellar absorption in its direction.