NGC 6231

Number of stars per data source

	Reference    1 :   10 stars
	Reference   41 :   37 stars

1: Walraven Th., Walraven J.H.; (1960) Bull. Astron. Inst. Netherlands 15, 67; A new photo-electric method of classification of luminosity and spectral type for O-and B-type stars; 1960BAN....15...67W
41: van Genderen A.M., Bijleveld W., van Groningen E.; (1984) Astron. Astrophys. Suppl. 58, 537; VBLUW photometry of the association Sco OB1 (containing the open cluster NGC 6231) a discussion on the evolutionary stars of the hypergiant Zeta1 Sco (B1Ia); 1984A&AS...58..537v