Abstract: The meteor activity of the delta Aquariids and Perseids has been observed by radio meteor observers worldwide. The delta Aquariids showed a peak time later than in previous years. The Perseids displayed the same usual activity level and also some unexpected activity.
Radio Meteor Observations in the world covered the meteor shower activity of the delta Aquariids and the Perseids 2020. Worldwide radio meteor observation data were provided by Radio Meteor Observation (RMOB) (Steyaert, 1993) and by the radio meteor observations network in Japan (Ogawa et al., 2001).
For analyzing worldwide radio meteor observation data, meteor activities are calculated by the “Activity Level” index (Ogawa et al., 2001). The activity profile was estimated by the Lorentz activity profile (Jenniskens, 2000).
3.1. delta Aquariids
Figure 1 shows the result for the delta Aquariids with 33 observations in 12 countries. The activity peak was estimated to occur around 08h UT on 28th of July (Solar Longitude λʘ = 125.45°). Distinct activity was given by three components. The first peak was around 24th of July (Solar Longitude λʘ = 121.8°). The main peak was 08h UT on the 28th of July. The last component had a peak around the 4th of August (Solar Longitude λʘ = 132.5°).
The long-term activity profile for the delta Aquariids for 2005–2020 is shown in Figure 2. The peak in the long-term activity is at Solar Longitude λʘ = 125.0° with full width half maximum (FWHM) –2.8°/+5.3°. The maximum activity level was 3.0.
One of the major meteor showers, Perseids displayed annual and unexpected activities based on 39 observations in 11 countries. The annual activity was estimated to have occurred around 17h on 12th August (Solar Longitude λʘ = 140.17°) with a maximum activity level = 1.2. The peak time was later than in the long-term activity data.
The unexpected activity was observed around 10h on 13th August. This activity level was higher than the annual activity. The activity profile shows the estimated peak time around 10h on 13th August (Solar Longitude λʘ = 140.85°) and activity level was 1.5. Last year, a sub-peak was also observed around Solar Longitude λʘ = 140.70°.
The long-term activity profile for the Perseids for 2001–2020 is shown in Figure 4. The peak is at Solar Longitude λʘ = 139.95° with full width half maximum (FWHM) –0.65°/+0.70°. The maximum activity level was 1.2. On the other hand, for the time period of the last ten years (2011–2020), the average activity level is 1.4 (higher than that of the long-term period).
The delta Aquariids and Perseids data were provided by the following observers:
Andrew Klekociuk (Australia), Chris Steyaert (Belgium), Johan Coussens (Belgium), test josephco_@_Graves (Belgium), Felix Verbelen (Belgium), DanielD SAT01_DD (France), Jacques Molne (France), Pierre Micaletti (France), Jean Marie F5CMQ (France), Fred Espey (Germany), WHS Essen (Germany), Per DL0SHF (Germany), Balogh Laszlo (Hungary), Istvan Tepliczky (Hungary), AAV Planetario_di_Venezia (Italy), GAML Osservatorio_Astronomico_Gorga (Italy), Mario Bombardini (Italy), Oss_Monte_San_Lorenzo DLF (Italy), Associazione Pontina di Astronomia _APA_ (Italy), Fabio Moschini_IN3GOO (Italy ), Hirofumi Sugimoto (Japan), Masaki Tsuboi (Japan), Kenji Fujito (Japan), Hirotaka Otsuka (Japan), Tomohiro Nakamura (Japan), Nobuo Katsura (Japan), Hironobu Shida (Japan), Masaki Kano (Japan), Salvador Aguirre (Mexico), Kees Meteor (Netherlands), Jose Carballada (Spain), Jochen Richert (Switzerland), Ian Evans (UK), Philip Norton (UK), Mike Otte (USA), Stan Nelson (USA), Eric Smestad_KC0RDD (USA), Steve ARS_KF3BH (USA).
Worldwide data were provided by Radio Meteor Observation Bulletin (RMOB) (http://www.rmob.org/).
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