1. Double station TV meteors and analysis of their trajectories Štork R., Koten P., Borovička J., Spurný P., Boček J. Astronomical Institute, Academy of Sciences of the Czech Republic, CZ–25165 Ondřejov, Czech Republic

2. Supported by the Grant Agency of the Czech Republic (GACR), grant No. 205/99/D097 and the scientific key project K3012103

3. Program and instrumentation TV observation of meteors in Ondřejov – since 1990 (spectral program) Double station observation in the integral light since 1998 Ondřejov – Kunžak base distance 92.5 km, Kunžak azimuth 340 degrees (south = 0)

4. Objectives Arsat 1.4/50 Image intensifiers DEDAL S-VHS camcorders Panasonic S-VHS videorecorders JVC diameter of the field of view about 20 degrees limiting magnitude 8 (stars), 6–7 (moving object – meteor)

5. Recorded meteors 1998–1999 57 hours of observation 472 double station meteors 207 of them digitized and measured 106 used for the following analysis (11 Gem, 8 Lyr, 14 Ori, 32 Per, 41 sporadic)

6. Beginning height of brighter meteors is higher (the fainter ones cannot be observed in those distances) Meteors of faster showers begin the luminous trajectory higher

7. Brighter meteors penetrate deeper (studying individual shower) Slower ones penetrate deeper Graph affected by the zenith distance of radiant (  Aquarids)

8. Data of slower meteors are more inaccurate Faster meteors – higher beginning heights (expected) Per, Ori higher then sporadic (not expected)

9. Data of slower meteors are more inaccurate Effect of zenith distance – low beginning height, high end height for  Aquarids

10. Effect of zenith distance

11. higher zenith distance of radiant more horizontal trajectory high end height

12. Bigger higher (in individual showers) Slower meteor showers – lower beg. height

13. Bigger deeper Slower deeper Geminids deeper

14. The graph shape is given by the definition Faster meteors are brighter

15. K B parameter K B = log  B + 2.5 log v  – 0.5 log cos z R  B = the air density at the beginning of the luminous trajectory (in g cm –3 ) v  = initial velocity (in cm s –1 ) z R = zenith distance of radiant Ceplecha Z. 1988, Bull. Astron. Inst. Czechosl. 39, p. 221–236

16. K B groups “asteroidal meteors”: 8.00  K B group A: 7.30  K B < 8.00 group B: 7.10  K B < 7.30; q  0.30 AU group C1: 6.60  K B < 7.10; a < 5 AU; i  35º group C2: 6.60  K B < 7.10; a  5 AU group C3: 6.60  K B 35º group D: K B < 6.60

17. The dependence is given by the definition  Aquarids shifted

18. sporadic: compact particles penetrate deeper group of cometary showers group of Geminids

19. sporadic: no fragile particles near Sun

20. ASTABC1C2C3D 0.523.43.330.914.623.04.3 weighted average of table in (Ceplecha 1988) 0.030.00.0 26.736.76.7 from our set of 30 high quality sporadic meteors Relative percent of meteoroids in individual groups

21. Conclusions Beginning heights of Ori and Per are higher then beg. heights of sporadic meteors with the same velocity No cometary (fragile) particles with low perihelion distance exist in our set of sporadic meteors Effect of zenith distance of radiant (  Aqr) appeared in K B graphs, where it would be corrected in definition of K B Although the distribution of our meteors to the classes AST, A, B, C, D agree with (Ceplecha 1988), the population of subclasses C1, C2, C3 disagree