{1} Astronomical Institute, 251 65 Ondrejov Observatory, Czech Republic
{2} Dutch Meteor Society, Lederkarper 4, NL-2312 NB Leiden, The Netherlands
Abstract. Spectra of two bright (-11 mag) Perseid meteors were studied. Monochromatic light curves were constructed and the spectra were also analyzed at selected points along the trajectory. The shift of maxima of low excitation iron lines down the trajectory in meteor flares was observed and explained by a longer radiative lifetime of the upper levels for these lines. Two spectral components with the temperatures of 4400-4800 K and 10 000 K, respectively, were identified in the spectra in accordance with previous findings. The ratio of both components, in term of mass, varied smoothly from about 100:1 over 15:1 to 30:1. This ratio is not an unambiguous function of meteor velocity, height and brightness but depends on the previous evolution of ablation. The abundances of heavy elements were found consistent with the chemical composition of carbonaceous chondrites and the dust of comet Halley. Hydrogen, however, was not more abundant than in carbonaceous chondrites and thus significantly less than in cometary dust. The initial masses of the two meteoroids were estimated to 40 g and 80 g, respectively. The meteor V-band luminous efficiency was found to vary in the range log tau_V = -11.8 to -12.0 in magnitude/c.g.s. units. For the panchromatic luminous efficiency we recommend to use the value of -11.4 for bright Perseids. Nearly 1.5% of meteoroid kinetic energy was radiated out in the Ca II lines and 1% in all other lines between 3500 and 6600 A.
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