[en] Meteor stream membership criteria used for evaluating potential associations between individual meteor orbits and the mean orbit of a stream are discussed on the basis of precise photographic orbits of some meteor streams (the Taurids, Geminids and Perseids). Serious shortcomings of the D-criterion are disclosed and suggestions of a more relevant use of the criteria for estimating stream memberships are presented, with attention paid to the distributions of the orbital elements of the streams. (author). 2 figs., 17 refs

[en] The Taurid meteor complex associated with P/Encke is studied on the basis of relevant photographic and radar orbits. Orbital characteristics, radiants and durations of the postperihelion showers are compared with corresponding theoretical values derived from the observations of the preperihelion Taurids. Reality of the proposed associations of minor showers with the Taurid complex and the total duration of its activity are evaluated and discussed. Some of the associated showers (the Northern and Southern χ Orionids, Northern Piscids and Southern Arietids) are confirmed to be in fact parts of the Taurid shower itself. (author). 3 figs., 5 tabs., 23 refs

[en] The radar observations of the Lyrid meteor stream at the Odrejov Observatory in 1980 to 1985 are analyzed and discussed from the viewpoint of determining the mass distribution exponent for overdense echoes in the range of 0.4 to 50 s. The mass exponent proved to be almost constant over the whole range of echo durations with s ∼1.58. The contribution of larger particles, as compared with other meteor streams was found to be more significant for the Lyrids. The almost constant value of s indicates a still active contribution of fresh cometary material to the stream. (author). 2 figs., 1 tab., 12 refs

[en] Large volume Ge-detectors have been used for the analysis of positron emitters of cosmogenic origin in extraterrestrial samples including lunar samples and meteorites. We present results from the analysis of ²⁶Al in the Rumanova chondrite which was found in 1994 in Slovakia. A slide of the meteorite was cut into ∼1 cm³ cubes which were analyzed in a coincidence Ge-NaI(Tl) spectrometer placed in a large shield measuring 1.5 x 1.5 x 2 m³, and consisting of iron, lead and copper layers. Operational characteristics of the spectrometer are presented and discussed, as well as the ²⁶Al profile observed in the meteorite. (author)

[en] Results of analysis of cosmogenic radionuclides (^57,58,60Co, ⁵⁴Mn, ⁴⁶Sc, ²²Na, ⁴⁸V and ²⁶Al) in fragments of the Kosice meteorite are presented and discussed. Analyses were carried out using a low-level HPGe-spectrometer placed in a lead-iron-copper shield. Twelve meteorite fragments were available for the analysis with masses from 27 to 2,163 g. The lowest massic activities were observed for ⁴⁶Sc (down to 0.1 mBq/g), and the highest for ²²Na (up to 2 mBq/g). The measured radionuclide activities showed differences between fragments, as indicated mainly by the ⁶⁰Co data, which were caused by different positions of meteorite fragments from the center of the meteorite body. (author)

[en] Analyses of the influence of solar activity on sporadic meteor counts based on visual and radar meteor observations present rather contradictory results, indicating a possible variation of the sporadic meteor counts with a solar activity, with the maximum in observed meteor rates occurring from zero up to about five years after the solar activity maximum. With this perspective, in the present paper observations of the sporadic meteor background, obtained by a forward-scatter radio system for meteor observation operating along the Bologna (Italy)-Modra (Slovakia) baseline in 1996-2007, are analysed and discussed. The activity curves of all echoes and their variations indicate a correlation with solar activity in the 23. solar cycle represented by the solar relative number R (corr. coef. 0.71), as well as with the solar coronal index C1 (corr. coef. 0.73). The mass distribution exponent s and its variations (with corr. coef. against R and C1, 0.12 and 0.25, respectively) does not show a correlation consistent with solar activity and, from the viewpoint of s, suggest the existence of a relatively stable population of sporadic background meteoroids in the surroundings of the Earth's orbit during the investigated period.

[en] On April 3, 2012 a single piece of a meteorite was found in the forest near Smolenice (Trnava County, Slovakia). The latitude and longitude of the find are 48 grad 31.2 'N and 17 grad 23.9 'E, respectively. The meteorite was slightly weathered (weathering grade W1) and its total mass was 13.95 kg. The bulk chemical composition is dominated by iron (88.7 wt %) and nickel (8.10 wt %). This, along with concentration of Ga (1.80 μg/g), Ge (< 0.7μg/g), and Ir (1.67 μg/g), suggest the meteorite being a IVA iron. Based on lamellae width of kamacite (average of 0.22 mm), the meteorite can be classified as fine octahedrite (Of). The mineralogy is very simple, the main minerals are iron (kamacite) (5.16 - 7.36 wt. % Ni) and taenite (16.73 - 33.93 wt. % Ni), with rare troilite nodules and daubreelite inclusions and thin veinlets. The meteorite shows Widmanstatten patterns and plessite structure is locally present. Analyses of cosmogenic radionuclides (²⁶Al, ¹⁴C, and ⁴⁰K) indicate that the radius of the Smolenice meteorite could be in the range of 30.50 cm, its terrestrial age of about 0.1 Ma and its cosmic-ray exposure age of about 0.2 Ma. (authors)

[en] A single 13.95 kg mass of a slightly weathered iron meteorite was found in the forest near Smolenice (48 grad 31.2'N, 17 grad 23.9'E; Trnava County, Slovakia). The bulk chemical composition (in wt. %) is: Fe 88.78, Ni 8.16, Co 0.38, P 0.05, S<0.006 and (in μg/g): Ge<0.18, Ir 1.67, Ga 1.80, Cr 87.3, Cu 135.1, As 4.52, Mo 5.82, Sn 1.53, W 0.56, Re 0.18, Ru 3.56, Rh 0.90, Pd 4.12, Pt 5.35, Au 1.19, Zn<5, B<0.68, Pb<0.06. Bulk geochemistry, and Ni, Ga, Ge and Ir contents in particular suggest that the meteorite is an octahedrite belonging to the IVA group. The average thickness of kamacite lamellae is 0.22 mm, ranking it as fine octahedrite (Of). The mineral composition is simple, the most abundant minerals being iron (kamacite) (5.16-7.36 wt. % Ni) followed by taenite (16.73-33.93 wt. % Ni). Troilite nodules and daubreelite inclusions and thin veinlets are rare. The Widmanstaetten pattern is uniform across the meteorite and plessite structure is developed locally. Analyses of cosmogenic radionuclides (¹⁴C and ²⁶Al) indicate that the radius of the Smolenice meteorite could be 30±10 cm and its terrestrial age 11±2 kyr. (authors)