Radar observation of the new λ-Sculptorid meteor shower

¹ Space Weather Laboratory, NASA Goddard Space Flight Center, Greenbelt MD USA
e-mail: diego.janches@nasa.gov
² Facultad de Ciencias, Universidad de la Republica, Montevideo, Uruguay
³ Centro Universitario Regional del Este, Universidad de la Republica, ruta nacional 9 y ruta 15, Rocha 27000, Uruguay
⁴ Department of Physics, Catholic University of America, DC, USA
⁵ Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada
⁶ Planetarium de Montreal, Montreal, Quebec, Canada
⁷ IMCCE, Observatoire de Paris, Paris, France
⁸ University Bern, Institute of Applied Physics, Microwave Physics, Bern, Switzerland
⁹ Estacion Astronomica Rio Grande, Rio Grande, Tierra del Fuego, Argentina
¹⁰ Investigador independiente, Buenos Aires, Argentina

Received: 8 April 2024
Accepted: 21 May 2024

Abstract

Context. 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.

Aims. We report the most comprehensive meteor radar observations of the λ-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.

Methods. 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.

Results. As predicted, the shower peak was observed by SAAMER-OS on December 12, 2023 (λ₀ = 259.73°) at 0900 UTC, with a Zenithal Hourly Rate (ZHR) peak value of ~2.5 m h⁻¹. Most of the activity of the shower was observed during 2 h between 0730-0930 UTC. The observed mean radiant of the shower in Sun-centered ecliptic coordinates is located at λ − λ₀ = 88.9° and β = −36.6°. Our results suggest that the particles detected by SAAMER-OS are in general larger than those for which thermal equilibrium can be assumed (>3 mg) in agreement with the conclusions of previous reports using video observations.