OB stars near the supernova remnant RCW 86.

The filamentary nebula RCW 86, identical with the nonthermal radio source MSH 14-63, is part of a supernova remnant. A group of OB stars is found near the radio source. The distance of the group is 2500 pc; this agrees well with the radio distance of the remnant. It is suggested that the remnant was formed by the explosion of a member of the group; the explosion occurred probably in 185 A. D.