Double station TV meteors and analysis of their trajectories Štork R., Koten P., Borovička J., Spurný P., Boček J. Astronomical Institute, Academy of Sciences.

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

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

key project K3012103

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)

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)

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)

• 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

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

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

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

Effect of zenith distance

higher zenith distance of radiant

more horizontal trajectoryhigh end height

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

• Bigger deeper• Slower deeper• Geminids deeper

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

KB parameter

KB = log B + 2.5 log v – 0.5 log cos zR

B = the air density at the beginning of the luminous trajectory (in g cm–3)

v = initial velocity (in cm s–1)

zR = zenith distance of radiant

Ceplecha Z. 1988, Bull. Astron. Inst. Czechosl. 39, p. 221–236

KB groups

“asteroidal meteors”: 8.00 KB

group A: 7.30 KB < 8.00

group B: 7.10 KB < 7.30; q 0.30 AU

group C1: 6.60 KB < 7.10; a < 5 AU; i 35º

group C2: 6.60 KB < 7.10; a 5 AU

group C3: 6.60 KB < 7.10; a < 5 AU; i > 35º

group D: KB < 6.60

• The dependence is given by the definition• Aquarids shifted

• sporadic: compact particles penetrate deeper

• group of cometary showers • group of Geminids

• sporadic: no fragile particles near Sun

AST A B C1 C2 C3 D

0.5 23.4 3.3 30.9 14.6 23.0 4.3

weighted average of table in (Ceplecha 1988)

0.0 30.0 0.0 0.0 26.7 36.7 6.7

from our set of 30 high quality sporadic meteors

Relative percent of meteoroids in individual groups

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 KB graphs, where it would be corrected in definition of KB

• 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