The ursid meteor outburst in 2020: preliminary results

Introduction: The Ursid meteor shower gives rise to an annual display of meteors from about December 17 to December 26, peaking on around December 23. Its activity is low, with a normal peak ZHR of about 10 meteors/hour. However, this shower exhibits activity outbursts that significantly increase this maximum zenithal hourly rate. These outbursts take place when the parent body of Ursid meteoroids, Comet 8P/Tuttle, is located at its perihelion or at its aphelion. One of these burst was predicted to take place in 2020. The Ursids have been monitored in the framework of the SMART project (Spectroscopy of Meteoroids in the Atmosphere by means of Robotic Technologies) since 2006. This survey, which is being conducted by the Southwestern Europe Meteor Network (SWEMN), employs an array of automated spectrographs deployed at 10 meteor-observing stations in Spain [1, 2]. SMART also provides valuable information for our MIDAS project, which we conduct to study lunar impact flashes [3-7]. With SMART we can determine the atmospheric trajectory of meteors and the orbit of their parent meteoroids, but also the evolution of the conditions in meteor plasmas from the emission spectrum produced by these events [8-15]. In this work we present a preliminary analysis of the Ursid outburst observed in December 2020, where several Ursid emission spectra were also recorded. Instrumentation and methods: The activity of the Ursids has been monitored by means of different instruments. To record meteor events and their emission spectra during the 2020 Ursid outburst we have employed an array of low-lux CCD video cameras manufactured by Watec Co. (models 902H and 902H2 Ultimate), some of which are configured as spectrographs by means of 1000 lines/mm diffraction gratings. CMOS color cameras were also employed [8]. These cameras monitor the night sky and operate in a fully autonomous way by means of software developed by J.M. Madiedo [1, 2]. The atmospheric trajectory and orbital data of the event were obtained with the Amalthea software, which was also written by the same researcher [9]. Besides, two forward scatter systems operating at two of our meteor-observing stations (Sevilla and La Hita) have been used to monitor the activity of radio meteors. The Ursid 2020 outburst: The activity of Ursid meteors was monitored in 2020 during the activity period of this meteor shower. Between 21 and 22 December, our forward-scatter systems located at La Hita and Sevilla recorded an enhanced activity. Our video devices observed this phenomenon on the night of 2122 December peaking around 22 December at about 5 UT, and revealed that this enhanced meteor activity was produced by Ursid meteors, and confirmed that the predicted Ursid outburst took place.