Mira Str.40-2, 222307, Molodechno Belarus
Abstract: This article presents the results of radio observations made in June 2021. The results of the radio observations are compared with the CAMS video network summaries.
The observations were carried out at a private astronomical observatory near the town of Molodechno (Belarus) at the place of Polyani. A 5 element-antenna directed to the west was used, a car FM-receiver was connected to a laptop with as processor an Intel Atom CPU N2600 (1.6 GHz). The software to detect signals is Metan (author – Carol from Poland). Observations are made on the operating frequency 88.6 MHz (the FM radio station near Paris broadcasts on this frequency). The “France Culture” radio broadcast transmitter (100 kW) I use is at about 1550 km from my observatory which has been renewed in 1997.
2 Automatic observations
The increased meteor signal activity from June 6–8 is associated with the peak of the Arietid (#0171) and zeta-Perseid (#0172) activity. The JBO peak activity (#0170) at the end of June was too weak or non-existent and it does not stand out in the overall activity profile. Similarly, the small daily showers of beta-Taurids (#0173) with a peak on June 28 (Rendtel, 2020) cannot be distinguished on the general activity profile.
Figure 1 shows the hourly rates of radio meteors in June 2021 at 88.6 MHz. Figure 2 shows the corresponding heat map.
3 Listening to radio echoes on 88.6 MHz
Listening to the radio signals 1 to 3 times a day for one hour was done in order to control the level of the hourly rates, as well as to distinguish between periods of tropospheric passage and other natural radio interference. The total effective listening time was 43 hours.
The broad high activity of June 9–12 is associated with ARI (#0171) and ZPE (#0172) daylight showers. The increased activity on June 21 may be associated, according to CAMS (Jenniskens et al., 2011), with increased activity of the June Aquilid NZC (#0164) and SZC (#0165) complex, and DPI (#0410).
In order to quickly search for signals of the radio fireballs, the program SpectrumLab was running in parallel to the Metan program. Screenshots were saved every 10 minutes. The search for fireball events was performed visually by viewing many thousands of screenshots obtained over a month. Then, we selected fireball events from the log files of the Metan program. For fireball activity statistics, I have selected signals from the log files with a peak power greater than 10000 as fireballs and with a signal duration greater than 10 seconds. Figure 4 shows the daily activity of the fireball radio signals. Figure 5 displays one of the fireball radio echoes.
For technical reasons, the Spectrum Lab program screenshots were not saved from June 1 to 7 and June 21 to 24.
5 CAMS Data
Figure 6 shows the total daily activity of meteors from the CAMS video network data (Jenniskens et al., 2011). There is a noticeable correlation between the activity level of sporadic meteors and the activity level of shower meteors.
CAMS data show peak activity around June 22. It is associated with an increase in the activity of the June Aquilid complex NZC (# 0164) and SZC (# 0165), as well as DPI (# 0410). The second increase in the activity of the Aquilid complex is detected on June 27-28.
Leaving aside the fact that the daytime meteor shower ARI (#0171) is poorly detected by CAMS video observation networks, there is a satisfactory correlation for the data obtained by the automatic method of observation, the method of listening to the radio echoes and CAMS video observation data. The method of automatic detection and the method of listening to signals recorded very well the activity of the daytime meteor shower ARI (#0171). Some discrepancy between the activity profiles can be explained by the different sensitivity of both methods. The listening method is more sensitive than the automatic detection method. Comparing the data obtained by both methods, one can more objectively understand what is happening in the meteoric sky in the radio range.
I would like to thank Sergey Dubrovsky for the software he developed for data analysis and processing of radio observations (software Rameda). I thank Carol from Poland for the Metan software. Thanks to Paul Roggemans for his help in the lay-out and the correction of this article.
Rendtel J. (2020). “Meteor Shower Calendar”. IMO.
Jenniskens P., Gural P. S., Dynneson L., Grigsby B. J., Newman K. E., Borden M., Koop M., Holman D. (2011). “CAMS: Cameras for Allsky Meteor Surveillance to establish minor meteor showers”. Icarus, 216, 40–61.