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Tima Sergienko

Publications and source records attributed to Tima Sergienko.

2 recordsLinked to original sources

Observations of the 2023 February 27 fireball in northern Sweden using the auroral imaging system ALIS_4D

On 2023 February 27 at 18:15:55.77 UT, a bright fireball streaked across the sky above northern Sweden. The event offered a valuable opportunity to study the phenomenon using an optical system primarily designed for auroral studies, the Auroral Large Imaging System (ALIS_4D), that captured the event. In this study we show the capability of ALIS_4D to perform observations in support of meteor event analysis. We estimated the trajectory from the recorded data and computed the orbit. In addition, we investigated the origin of the meteoroid searching for its parent body. Fitting the analytical ablation model known as $\alpha$-$\beta$ to the trajectory as well as incorporating local wind-field data in Monte-Carlo dark-flight simulations, strewn-fields were computed and physical properties of the meteoroid were estimated. Trajectory analyses delineate a strewn field along the border between Kiruna and G\"allivare in northern Sweden. Our findings indicate that the meteoroid's parent body was likely an Apollo family object. We performed an orbital similarity analysis to identify candidate parent bodies of the fireball. Our simulations suggest that close approaches with Earth could have disrupted the meteoroid's orbit, placing it on a collision course.

astro-ph.EP

Eastward-expanding auroral surges observed in the post-midnight sector during a multiple-onset substorm

We present three eastward-expanding auroral surge (EEAS) events that were observed intermittently at intervals of about 15 min in the post-midnight sector (01:55-02:40 MLT) by all-sky imagers and magnetometers in northern Europe. It was deduced that each surge occurred just after each onset of a multiple-onset substorm, which was small-scale and did not clearly expand westward, because they were observed almost simultaneously with Pi 2 pulsations at the magnetic equator and magnetic bay variations at middle-to-high latitudes associated with the DP-1 current system. The EEASs showed similar properties to omega bands or torches reported in previous studies, such as recurrence intervals of about 15 min, concurrence with magnetic pulsations with amplitudes of several tens of nanotesla, horizontal scales of 300-400 km, and occurrence of a pulsating aurora in a diffuse aurora after the passage of the EEASs. Furthermore, the EEASs showed similar temporal evolution to the omega bands, during which eastward-propagating auroral streamers occurred simultaneously in the poleward region, followed by the formation of north-south-aligned auroras, which eventually connected with the EEASs. Thus, we speculate that EEASs may be related to the generation process of omega bands. (Continued)

physics.space-ph