Spectral Classification of Stars in A Supplement to the Bright Star Catalogue MK spectral types are given for about 584 stars in A Supplement to theBright Star Catalogue. These are compared with Hipparcos parallaxes tocheck the reliability of those classifications. The estimated errors are+/-1.2 subtypes, and 10% of the luminosity classes may be wrong.
Photoelectric filter photometry of the flux depression at 5200 A in Ap-stars A new photometric index was used to characterize the flux depression at5200 A in a photoelectric filter photometric study of a large number ofnormal A-stars, Ap-stars, Am-stars, and Hg-Mn-stars. The new index isdefined as a = g - (h + y)/2, where g and h are the brightnesses at 5240and 5020 A, respectively, measured by interference filters, and y is thebrightness measured with a Stromgren filter. The index reveals a markedcontrast between normal and peculiar stars.
