Leonids 2025: prediction of activity
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Fig. 1. Space-temporal projection of Leonids trails parts onto their minimal distance passages in 2025 (correspondence between colours of the particles and their ejection velocities can be seen here).

Fig. 2. Assumed profile of overall Leonid activity (blue line) and its background component (red line).

A number of encounters with 1699 trails is found for 2025. This trails is quite old but it encounters the Earth with its relatively regular parts:
TrailrD-rE, AUVej, m/sfM(fMD)Sol.log., deg.Time, UT
1699-0.0018222.010.229235.30117.11.2025 18:27
1699-0.00174-21.92-0.359235.30117.11.2025 18:27
16990.00015-19.540.060235.32717.11.2025 19:05
16990.00020-19.42-0.165235.33417.11.2025 19:15
1699-0.00062-17.31-0.423235.47317.11.2025 22:33
These fragments pass at quite small distance but they are formed by particles with significant negative ejection velocities, from -17 to -22 m/s. Therefore the probability of any significant activity increase is not high, as many smaller particles are blown away by solar radiation pressure from such trail parts. However some larger particles still could be present so the number of bright meteors could increase during the period from 18 to 23 UT on November 17. In any case it recommended to pay higher attention to this period of time during the observations of Leonids-2025 activity.


1. "Comet's dust 2.0" program by S. Shanov and S. Dubrovsky. [Used for orbital computations.]
2. E. Lyytinen, T. van Flandern "Predicting the strength of Leonid outbursts", 2000, Earth, Moon, and Planets, P. 149-166.
3. Jenniskens P. Meteor showers and their parent comets, 2006, 780 p. 4. Kasuo Kinoshita, http://jcometobs.web.fc2.com/ [Orbital elements of the comet 55P Tempel-Tuttle]