Beta Leonids

Observing

The duration of this meteor shower extends from February 14 to April 25. Maximum occurs around March 20 (λ=0°), at which time the radiant is located at RA=177°, DEC=+11°. The maximum ZHR is probably 3-4.

History

The Beta Leonids were apparently first observed by E. R. Blakeley (Dewsbury), when he plotted five slow meteors from an average radiant of RA=175°, DEC=+10° during March 16-26, 1895.

Although the Beta Leonids were not widely reported on an annual basis, some sources reveal they were active. In Cuno Hoffmeister's 1948 book Meteorströme, five visual radiants are listed as having been observed during the 1930's. Radiants 1607 and 1623 were detected in 1931. The former radiant was detected on March 19 (λ=357.0°), from RA=179°, DEC=+8°, while the second radiant was observed on March 21 (λ=358.7°), from RA=182°, DEC=+15°. Radiants 2960 and 3108 were both observed 0n March 23, 1933: the former occurring at a solar longitude of 1.0°, from RA=187°, DEC=+12°, while the second occurred from λ=0.7°, from RA=183°, DEC=+10°. Finally, radiant 5029 was observed on March 20, 1936 (λ=358.1 deg), from RA=182°, DEC=+15°.

The Beta Leonids were missed by radio-echo surveys until the 1968-1969 session of the Radio Meteor Project. Zdenek Sekanina determined the shower's duration as extending from February 14 to April 25. He said the nodal passage occurred on March 23.0 (solar longitude=1.9 deg), at which time the radiant was at RA=180.7°, DEC=+11.5°. Sekanina had referred to this stream as the March Virginids. It should be noted that the nodal passage may have actually occurred earlier than indicated, since the radar equipment was not in operation during March 20-22---the probable date of maximum activity.

The most recent observations of this shower come from members of the Western Australia Meteor Section (WAMS). In 1980, they detected shower meteors during March 14-23. Maximum came on March 19, when the ZHR reached 3.46+/-0.86. The radiant was determined as RA=176°, DEC=+15°.

A search through the various lists of photographic meteors reveals 14 probable Beta Leonids. The indicated duration is February 24 to April 11. Interestingly, two clusters occur in the data: the first is around March 5-6 (solar longitude=344 deg-345 deg), while the second is around March 18-19 (solar longitude=358 deg-359 deg). These two clusters cause the average orbit to possess a nodal passage date of March 12, at which time the radiant position is RA=168.4 deg, DEC=+12.6 deg. This strange grouping of the data distorts the average radiant position of this shower. The actual position for March 18-19, based on 3 photographic meteors, is RA=173°, DEC=+9.7°.

The existence of two dates of maximum in the photographic data is difficult to account for. Also difficult to explain is how so many photographic meteors could have been overlooked in the various computerized stream searches conducted during the 1960's and early 1970's. A possible explanation for the latter question is found in one of Bertil-Anders Lindblad's 1971 computerized searches. He had identified 24 meteors as belonging to the Delta Leonids of February. The Author finds that several of the Beta Leonid meteors of early March were included in Lindblad's data. By comparing the orbits of these two streams it can be seen that they do have distinct differences.

The Author has plotted the radio meteors, photographic meteors and available visual radiants and determined the daily motion of this shower as +0.9° in α and -0.4° in δ.