Prediction of Leonids in 2004

By Mikiya Sato

2004 Oct.26 : This page was opened.
2004 Oct.29 : Some data were corrected.

I calculated the dust trail which will return in 2004, from Comet 55P/Tempel-Tuttle. Although Leonids appeared actively from 1998 to 2002, a high-scale shower is not expected this year from my result.
However, a small shower may be seen from some trails. The distribution of the dust trais are shown in Fig.1 and Fig.2.

Fig.1 Position of tha new trails. (1932 and 1965)

Fig.2 Position of tha main trails.
All trails : Ejected from 1699 to 1899.
Old trails : Within 0.003 [AU], ejected from 901 to 1666.

From these, the trails which approaches the earth within 0.003[AU] this year were summarized in Table 1. (Detailed data table is hear.)

Table 1. Data of trails which approaches the earth within 0.003[AU]
Year of
Speed [m/s]
Expected peak level
1965120.961.35Nov.1709:22235.315-0.00170.94153.6121.6270.81No peak
173320.820.22Nov.1921:26237.840-0.00230.10155.1920.7670.80Middle scale peak
133314.270.14Nov.1906:39237.218+0.00180.022154.9521.2870.64Low level peak
116713.100.13Nov.2109:54239.374+0.00290.0049156.2720.5470.67No peak
113511.750.12Nov.2108:21239.309+0.00060.0040156.2120.4870.73Low level peak?
dR: R(Trail) - R(Earth)
Notice: The data of 1965 was recalculated. And each values of fM were corrected. (Oct.29)

The comment about each trails

Trail from 1965
Discharge speed was very large (about 120[m/s]). Therefore, it is surmised that meteor hardly appears, or meteor magnitude is very dark.

Trail from 1733
The peak from this trail has a high possibility of being observed. In 2003, Leonids had the middle scale peak (zhr;about 60) at 236.8 deg of solar longitude. This peak is considered to be a peak of the trail from 1733. The situation this year resembles the situation last year (the approach distance this year is nearer, but the fM value last year was larger). So there may be an appearance of the same level as last year.

Table 2. Comparison of trail data from 1733, between last year and this year.
YearYear of
Speed [m/s]
2003173317.32236.888+0.00360.16ZHR about 60

Trail from 1333
The fM value is low (0.022), and approach distance is not so near (0.0018[AU]). So the peak will be a low level if the peak is observed.

Trail from 1167
The fM value is very low (0.0049), and approach distance is not near (0.0029[AU]). So the peak will be not observed.

Trail from 1135
The fM value is very low (0.0040). But the approach distance is very near, 0.0006[AU]. So a small peak may be observed. If the meteor is appeared, the magnitude will be brighter than other trails because the discharge speed is so low (11.75[m/s]).