June Bootids 1901-2100
to the list of predictions
Today meteor shower activity remains one of the most unpredictable astronomical phenomena. Scientists learned how to make very detailed predictions of such events as solar and lunar eclipses, planetary transits on the Sun. Evolution of main bodies in the Solar system can be computed for many thousand years to the past and future, for asteroids such computations are made at least for hundreds of years (the most important purpose is search for those of them which can collide with the Earth). At the same time, meteor showers, whose activity in astronomical terms occurs literally side by side to the Earth, continue to surprise us.
During many decades meteor astronomers tried to predict meteor activity using different criteria. But it was a sort of guessing. In some cases their expectations realized, although often meteor activity anyway caused a stir in some aspects (for example, occurring at not expected time or giving strong fireball activity). Sometimes such forecasts proved to be completely wrong.
The method of meteor activity prediction with the use of computation of meteor particles orbital evolution after their ejection by a comet become more widespread in 1990s. Earlier its use was restricted by low computing abilities of computers. But such Russian forecasters as V.V. Reznikov and E.A. Emel'yanenko had already issued their computations for Leonids, Draconids, Bielids and some other showers. By the end of 1990s, when computers became powerful enough, several researchers, - Robert MacNaught, David Asher and Esko Lyytinen, - published their predictions of Leonid activity for several nearest years.
Of course, mainly due to the lack or inaccuracy of initial orbital elements of parent comets, as well as probable imperfections in the method itself, its reliability is still lower than desired. Serious faults in maximum time accuracy and especially intensity of outbursts are still very typical for meteor predictions, as well as cases of their failure (the last such situation was with predicting activity of Draconids 2005). Nevertheless, it is obvious that this method is a large step forward comparing to predictions on the base of distances between the Earth orbit and orbital nodes of parent comets and times of their passage by the Earth.
Observing data allowed to build a model for calculation expected ZHR of meteor outbursts. Such a model, created by E. Lyytinen and T. van Flandern and presented in , was taken by the Author as the base for computation of expected intensity of June Bootids outbursts.
June Bootids forecasting by some reasons became less widespread than, say, Leonids. As far as we know, the single case of successful prediction of future activity were June Bootids 2004. The first who mentioned this case was E.A. Reznikov, which was followed by S. Shanov and S. Dubrovsky, then their computations were confirmed by other researchers. Reznikov also gave prediction for the shower outburst in 1998, but this forecast wasn't widely known among observers in the world, so this outburst turned to be unexpected. Among the recent results some computations made by J. Vaubaillon, M. Sato and I. Sato are presented in . For the period 1901-2100 they show some relatively close encounters between the Earth and the trails of the comet 7P. Those years are: 1910 (1808, 1813, 1819, 1825 trails (Vaubaillon), no activity reports), 1916 (1813, 1819, 1825, 1830, 1836 trails (Vaubaillon), 1819 trail (M. Sato), 1819 trail (I. Sato), observed activity with ZHRmax of 200+\-50), 1917 (1847, 1852 trails (Vaubaillon), no activity reports), 1921 (1802 trail (Vaubaillon), 1758 trail (I. Sato), observed activity with ZHRmax of ~7+\-5), 1923 (1808, 1813 trails (Vaubaillon), no activity reports), 1927 (1802 trail (Vaubaillon), 1784, 1790 trails (I. Sato), observed activity with ZHRmax of ~350), 1936 (1852 trail (Vaubaillon), observed low telescopic activity), 1942 (1825, 1830 trails (Vaubaillon), no activity reports), 1954 (1808 trail (Vaubaillon), no activity reports), 1967 (1808, 1813 trails (Vaubaillon), no activity reports), 1973 (1808 trails (Vaubaillon), no activity reports), 1986 (1819, 1836 trails (Vaubaillon), no activity reports), 1992 (1813 trail (Vaubaillon), no activity reports), 1993 (1796 trail (Vaubaillon), no activity reports), 1998 (1808, 1813, 1819, 1825, 1830, 1836, 1841, 1847, 1852 trails (Vaubaillon), 1825 trail (M. Sato), observed activity with ZHRmax of ~250+\-550), 2004 (1813, 1819, 1825, 1830, 1836, 1841, 1847, 1852 trails (Vaubaillon), 1813, 1819, 1825, 1830 trails (M. Sato), observed activity with ZHRmax of ~18+\-2), 2010 (1819, 1825, 1830, 1836 trails (Vaubaillon), in future), 2028 (1796 trail (Vaubaillon), in future).
1. "Comet's dust 2.0" program by S. Shanov and S. Dubrovsky. [Used for orbital computations.]
2. Kazuo Kinoshita, 7P detail, http://www9.ocn.ne.jp/~comet/pcmtn/007p.htm.
3. Lyytinen E., van Flandern T. "Predicting the strength of Leonid outbursts", 2000, Icarus, P. 158-160.
4. Jenniskens P. Meteor showers and their parent comets, 2006, 780 p.