Delta Arietids

First recognition of a possible December radiant near Delta Arietis was made by R. E. McCrosky and A. Posen in 1959, while analyzing the photographic meteor orbits obtained by the Harvard Meteor Project during 1952-1954. Seven meteors indicated a shower was active during December 8-13, with a probable maximum on the 8th. The average radiant was given as RA=51°, DEC=+21°. In 1971, a computerized stream search of the same 1952-1954 photographic meteors by B.-A. Lindblad, revealed the Delta Arietids to be split into northern and southern branches; however, among the 14 meteors, which suggested a duration of December 8-January 2, only 2 were from the southern branch. The average radiant of the northern branch was RA=54°, DEC=+25°.

No trace of this stream seems to be present in records covering the 19th century, but the first appearance of shower members may have occurred early in the 20th century, when several fireballs appear in various sources. The first really good visual radiants from this stream appeared during 1912 and 1932 and were published in C. Hoffmeister's 1948 book Meteorströme. The most detailed observation obtained thus far was by observers in Waltair, India, on December 8, 1964. M. Srirama Rao, P. V. S. Rama Rao and P. Ramesh plotted 10 meteors from RA=57 deg, DEC=+22 deg and concluded that the radiant produced a rate of 7.5 meteors per hour. However, numerous observers' attempts to observe the shower during the 1970's and 1980's have never shown hourly rates greater than one at the time of the predicted maximum.