Engineering topics
Publications and source records attributed to Brown, A..
IUE far ultraviolet echelle spectra of three active chromosphere dwarf stars X1 Orionis (GO V), Bootis A (G8 V), and Eridani (K2 V), are analyzed utilizing spectra of Alpha Cen A (G2 V) and Alpha Cen B (K1 V) as quiet chromosphere comparisons.
It is shown that the relative intensities of emission lines within the multiplet UV 0.01 of C II, around 2325 A, are sensitive to electron density in the range 10 to the 9th to 10 to the 7th per cu cm. The lines therefore offer a valuable method for measuring electron densities in the chromospheres of late-type giants and supergiants. Calculated line ratios are compared with those observed in a range of objects.
Observations alpha Tau (K5III) and beta Gru (M2II) made at high resolution are used to confirm line identifications of features blended at low resolution. The high resolution spectra allow selected pairs of lines to be used to find the electron density and the opacity. Methods for determining these factors and the usual emission measure are presented. The electron density and opacity can be used together with the emission measure to place constraints on the structure of the atmosphere. The line formation processes are briefly discussed. Photo-excitation by strong lines appears to be important in these late type atmospheres.
Logic networks of Boolean analogs analyzed by algebraic signal flow theory, introducing variational derivative for test detection in combinational and sequential networks