June Bootids (from 7P Comet Pons-Winnecke) in 2004

Recent meteor shower of June Bootids occured in 1998. This meteor shower may happen again in 2004. But the trails which cause meteor shower in 2004 are disturbed. The cause is approach to the earth in 1910 and 1916.

I explain using a trail which were ejected from 1819. This trail approached the earth first in 1910. For this reason, a part of the trail was devided into A1 and A2 (fig.1) in 1916 of the next return. Furthermore, the trail carried out 2nd approach to the earth at this time (it became a meteor shower).

And the trail was further divided into B1 and B2 at the return in 1922. By these transitions, the separated part between A1 and B2 arose in the trail.

Then, this part of trail approaches with Jupiter several times, and was influenced of perturbation due to Jupiter. And the edge of the part of trail (A1) will approach with the earth in 2004.

The distribution of the dust trais are shown in fig.2. Some parts of trails are likely to approach with the earth. Fig.3 is an expansion display in a part of fig.2.

It is expected that four parts of trails approach. The details are summarized in Table 1. and fig.4.

Table 1. Results of tha positions of trails in 2004.

Year of ejection	Discharge speed [m/s]	Date	Time	delta r [AU]	Alpha	Delta	Velocity [km/s]
1830-1	8.155	Jun. 23	13:45	+0.0033	223.0	+47.1	14.14
1830-2	8.169	Jun. 23	14:17	+0.0064	223.5	+47.3	14.12
1825-1	8.834	Jun. 23	14:46	+0.0031	223.0	+47.0	14.13
1825-2	8.859	Jun. 23	15:36	+0.0115	224.2	+47.6	14.08
1819-1	10.377	Jun. 23	16:32	+0.0062	223.4	+47.2	14.10
1819-2	10.388	Jun. 23	16:29	+0.0098	224.0	+47.6	14.09
1813-3^(1*	13.166	Jun. 23	16:09	-0.0040^(2*	221.6	+46.7	14.17
1813-2	13.290	Jun. 23	19:32	+0.0034	223.1	+46.9	14.10
1813-1^(1*	13.291	Jun. 23	19:15	+0.0045^(2*	223.1	+47.0	14.10

(1*: Mistaken data was corrected on Sep.26. (Each data was interchanged.)
(2*: Mistaken data was corrected on Sep.26. (Each data was interchanged.)

Therefore, the meteor shower in 2004 is expected about 13:00 - 20:00(UT) on Jun. 23. However, since the trails are disturbed, the hourly rate in 2004 will be fewer than that in 1998.

Addition 1;
This result is from the method assumes the meteoroid stream to be formed as a comet passes perihelion. If dust is ejectted before and after perihelion, it may approach more nearly to earth. In this case, the difference for dozens of minutes will arise at the peak time.

Addition 2;
The meteor from other trails (ejected after 1836) may appear if these distributions of trails are large.

The case which the dust was ejectted before and after perihelion

It is expected that three parts of trails cross. The details are summarized in fig.2-1 and Table 2-1.

Table 2-1. Results of tha positions of trails in 2004.

Year of ejection (1*	Time difference with perihelion [day]	Discharge speed [m/s]	Date	Time (UT)	R.P.		Velocity [km/s]
Year of ejection (1*	Time difference with perihelion [day]	Discharge speed [m/s]	Date	Time (UT)	Alpha	Delta	Velocity [km/s]
1830	-104.8^(2*	13.81	Jun. 23	12:30	222.5	46.8	14.14
1825	-74.7	12.72	Jun. 23	13:45	222.4	46.8	14.13
1819	-60.1^(2*	13.57	Jun. 23	15:31	222.5	46.7	14.12

(1*: Year of perihelion.
(2*: Mistaken data was corrected on Sep.26. (Each data was interchanged.)

From the above result, a possibility that meteor would appear was suggested around 12:00-16:00(UT). However, the activity of a comet when dust was ejectted is about 20% (1830) - 40% (1819) at the time of perihelion.

LINK

Return