Radar observation of the new λ-Sculptorid meteor shower

Abstract

46P/Wirtanen is a near-Earth comet (NEC) and several previous modeling works had predicted it would produce a meteor shower for the first time on December 12, 2023. We report the most comprehensive meteor radar observations of the lambda -Sculptorid meteor shower produced by comet 46P/Wirtanen. These measurements are critical to constrain the mass distribution of the particles released by the comet as radars generally detect the smaller particle population of the shower. We utilized observations with the Southern Argentina Agile Meteor Radar - Orbital System (SAAMER-OS) ideally located in the southern hemisphere to detect this shower. Since the shower was predicted to produce very slow meteors, we used the same methodology applied for the Arid meteor shower. As predicted, the shower peak was observed by SAAMER-OS on December 12, 2023 ($ circ $) at 0900 UTC, with a Zenithal Hourly Rate (ZHR) peak value of sim 2.5 meteors per hour. Most of the activity of the shower was observed during two hours between 0800 and 0900 UTC. The observed mean radiant of the shower in Sun-centered ecliptic coordinates is located at $ circ $ and beta = -36.6$^ circ $. Our results suggest that the particles detected by SAAMER-OS are in general larger than those for which thermal equilibrium can be assumed ($>$ 3mg) in agreement with the conclusions of previous reports using video observations.