Meteoroids near the Earth-Moon system as inferred from temporal and spatial distribution of impacts detected by the lunar seismic network

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6741930

Oberst, P J

The meteoroid impacts detected by the lunar seismic station network are examined in terms of (a) the distribution of impact locations and energies, (b) the diurnal variation of impact rate, and (c) temporal clustering. Small meteoroids (estimated masses smaller than 1 kg) and large meteoroids (estimated masses larger than 1 kg) are found to differ significantly in their temporal distributions. Small meteoroids show strong clustering. Several known cometary showers are identified among the clusters; the Perseids, Leonids, Aquarids, Orionids, and Geminids being the most prominent. The majority of the detected objects approaches at high speeds from highly inclined orbits. In contrasts, large meteoroids travel predominantly in orbits of low inclination and show little clustering. The average impact flux of these large objects is estimated to be log{sub 10}n(E) = {minus}0.99 log{sub 10} E + 11.38 for the energy range 2 {times} 10{sup 11} J to 2 {times} 10{sup 12} J, where n is the cumulative number of meteoroids having kinetic energies greater than E, in Joule, impacting the lunar surface. This agrees within a factor of five with flux rates of terrestrially observed airwave objects (very large meteoroids) and flux rates estimated from lunar crater statistics. Sources of the small-mass meteoroids are suggested to be mostly long-period comets. The diurnal distribution of the detected large-mass meteoroids indicates that most of them do not represent high-density meteorites but low-density material too fragile to survive the terrestrial atmospheric entry. These large objects are probably derived from short-period comets and low-density members among the near-Earth asteroids.

• Research Organization: Texas Univ., Austin, TX (USA)
• OSTI ID: 6741930
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
METEOROIDS
SEISMIC DETECTION
MOON
SEISMIC SURVEYS
ASTEROIDS
COMETS
CORRELATIONS
DAILY VARIATIONS
DENSITY
DISTRIBUTION
EARTH PLANET
IMPACT SHOCK
ORIGIN
PLANETARY ATMOSPHERES
SEISMIC ARRAYS
TIME DEPENDENCE
VARIATIONS
WEIGHT
ATMOSPHERES
DETECTION
GEOPHYSICAL SURVEYS
MEASURING INSTRUMENTS
PHYSICAL PROPERTIES
PLANETS
SATELLITES
SURVEYS
640107* - Astrophysics & Cosmology- Planetary Phenomena