Sigma Leonids

History

The strongest evidence supporting this stream's existence comes from the 1961-1965 session of the Radio Meteor Project. Z. Sekanina isolated 16 meteors during the period of February 9-March 13. The date of the nodal passage was given as February 26.2 (λ=337.1°), at which time the radiant was α=169.4°, δ=+14.4°.

Searches through past records have revealed a few possible observations of this shower: On March 3.5, 1886 (UT), W. F. Denning observed a 2nd-magnitude stationary meteor at α=176°, δ=+9°; E. Opik plotted several meteors during February 29 and March 1, 1932, which indicated a radiant of α=168°, δ=+15°; During February 27-28, 1947, V. Anyzeski plotted 4 meteors from α=163°, δ=+14°. In addition, three photographic meteors were found in McCrosky and Posen's 1961 paper. These meteors were detected on February 5, 1953 (α=146°, δ=+22°), February 3, 1954 (α=147°, δ=+20°) and March 1, 1954 (α=167°, δ=+12°).

Since the shower's official announcement in 1973, by Sekanina, only one notable observation of activity has been made. During February 23-March 11, 1979, members of the Western Australia Meteor Section observed this shower and noted that a maximum ZHR of 1.23+/-0.67 came on February 25, from α=170°, δ=+7°.

The Author combined the radio and photographic meteors and noted a daily motion of +0.93° in α and -0.40° in δ.