Zeta Perseids

Observing

This daylight shower occurs during May 20 to July 5. Maximum occurs on June 13, from an average radiant of RA=63°, DECL=+26°. Radar surveys have revealed the activity of this shower to be near 40 per hour. The daily motion of the radiant amounts to +1.1° in RA and +0.4° in DECL.

History

The Zeta Perseids were discovered in 1947 by operators of the radio equipment at Jodrell Bank (England). Only rough details were available at that time, with the duration being determined as June 2-17, and the radiant being estimated as falling within the range of RA=52 deg to 62 deg, DECL=+15 deg. Jodrell Bank observations continued during 1949 and 1950, with A. Aspinall and Gerald S. Hawkins establishing a duration of June 1-16 and a typical radiant diameter of less than 3 deg. The average radiant position was given as RA=61.6 deg, DECL=+23.8 deg.

A radar study was conducted by B. L. Kashcheyev and V. N. Lebedinets during 1960, using equipment at the Kharkov Polytechnical Institute (USSR). The analysis revealed a duration of May 4 to June 19, with the nodal passage coming on June 2 (Solar Longitude=71 deg), and the average radiant being RA=52 deg, DECL=+23 deg.

During the first session of the Radio Meteor Project, Zdenek Sekanina determined the duration as May 20 to June 21. The date of the nodal passage was given as June 8.9 (Solar Longitude=77.6 deg), at which time the radiant was at RA=60.2 deg, DECL=+24.8 deg. During the 1968-1969 session, Sekanina determined the duration as May 22-July 4. The date of the nodal passage was then given as June 12.2 (Solar Longitude=80.8 deg), while the average radiant position was determined to be RA=63.3 deg, DECL=+27.1 deg.

Two radar studies were conducted using equipment at the University of Adelaide (South Australia) during the 1960's. Unfortunately they were operated over periods of about a week, so that their results might be considered somewhat misleading when considering the radiant position and orbit. The first operated in 1961, when C. S. Nilsson detected the Zeta Perseids during June 13-16, and determined the radiant as RA=64.2 deg, DECL=+25.4 deg. He mentioned that the equipment had also been operated during May 19-28, and that a radiant at RA=44.3 deg, DECL=+19.5 deg was probably the same as the June shower. The second survey was conducted during June 9-14, 1969 by G. Gartrell and W. G. Elford. It revealed a radiant at RA=65 deg, DECL=+27 deg, and the authors showed that the stream was probably the twin of the Southern Taurids of November.

From observations made in the United States and Australia during 1971, it appears that meteors from this shower can be visually detected coming up from the horizon during the hours immediately after sunset and immediately before sunrise. Daryl Skelsey (Sydney, Australia) observed 1 Zeta Perseid during 2 hours on June 5/6, while Karl Simmons estimated that the combined rates of the Zeta Perseids and Arietids reached 1 to 2 meteors per hour on the morning of June 6/7.