Gamma Virginids

The discovery of this meteor shower should be attributed to A. S. Herschel, who plotted 12 meteors from a radiant of RA=192°, DECL=+4° during April 10-11, 1864. During April 16 to 25, 1895, W. Doberck plotted 7 meteors from a similar radiant at RA= 190.5°, DECL=+7°.

Aside from a few scattered fireballs and radiants between 1895 and 1963, the decade containing the most observations of this stream was the 1930s. C. Hoffmeister, in his 1948 book Meteorströme, listed four radiants (numbers 1628, 2103, 3156 and 5266) observed during 1931 to 1934. As a group, these radiants spanned across the period of solar longitudes 16.8 deg to 31.5 deg. Also during the same period, R. A. McIntosh observed two radiants which he combined into a radiant he designated number 91 in his "Index to Southern Hemisphere Meteor Showers". Occurring during the period April 12 to 16, the radiant moved from RA=184°, DECL=0°, to RA=188°, DECL=0°.

The Author has accumulated 26 meteor orbits from the photographic catalogs and Sekanina's raw data obtained during the two sessions of the Radio Meteor Project. The average position of the radiant is RA=185.0°, DECL=-0.7°. The indicated daily motion is +0.70° in RA and +0.16° in DECL. When the shower first becomes active on April 5 (Solar Longitude=15°) the radiant is at RA=180.7°, DECL=-1.7°, and when the last traces occur on April 21 (Solar Longitude=31°) the radiant is at RA=191.8°, DECL=+0.9°. These values are, however, tentative as the radar meteors tend to fall from the southern part of the radiant, while the photographic meteors fall from the northern part. This setup may be due to the differences in the average semimajor axes of the two types of meteors or just a curiosity that develops due to a lack of data.

Among the several meteor showers emanating from the Virgo-Libra region during April, this meteor stream stands out from the rest due to its large perihelion distance of about 0.82 AU (compared to 0.1 to 0.4 AU for the rest of these streams). This stream is similar to the other streams as it occurs especially close to the ecliptic. Subsequently, both photographic and radar meteors tend to possess two orbits---each separated by 180 deg in the ascending node and argument of perihelion. The orbits represented below belong to the most commonly occurring orbit. The Gamma Virginids are sometimes included in lists of showers belonging to the Virginid complex of meteor showers.