Spectral types and Hγ (W Hγ) equivalent widths have been derived from low dispersion (92 Å/mm and 51 Å/mm) spectrograms of the brightest stars in NGC 281, NGC 1893 (Aur OB 2), NGC 6823 (Vul OB 1), NGC ...

The principles involved in setting up any viable system of spectral classification are discussed. Their application is illustrated by reviewing the essential features of the original MK system of two ...

Stellar spectral types were initially arranged alphabetically; however, subsequent detailed observations led to the consolidation and reordering of categories, establishing the current OBAFGKM ...

Dielectric spectroscopy is a type of impedance spectroscopy that measures the dielectric properties of a system as a function of frequency. The external field interacts with the dipole moment of the ...

Electrochemical impedance spectroscopy (EIS) is an analysis method used the surfaces of various systems, batteries, photovoltaic systems, and some life science applications. It is based on introducing ...