Plate 15: Luminosity Effects at B5

Star Index

Plate 15: Luminosity Effects at B5

All spectral lines at Class B5 (except those of the Balmer series of hydrogen) are weak on spectrograms of the scale (~126 A/mm) shown here. Spectrograms having scales near 40 A/mm are necessary for the determination of precise spectral types for the B5 stars; on the other hand, luminosity classes of good accuracy can be determined from the intensities and widths of the Balmer lines on spectrograms like those illustrated.

The lines of He I tend to weaken on passing from luminosity class V to III.

Valid XHTML Created by diploma on 27/07/04