A decadal survey of the Daytime Arietid meteor shower using the Canadian Meteor Orbit Radar

We present results from a 12 year survey of the Daytime Arietid meteor shower using the Canadian Meteor Orbit Radar, a VHF backscattering orbital meteor radar, covering the interval 2002–2013. This survey recorded more than 2 × 104 Daytime Arietid orbits having representative masses of 8 × 10−8 kg and sizes of ≈0.4 mm. The core activity for the Arietids is found in the range 73| $_{.}^{\circ}$|5 ≤ λ⊙ ≤ 84| $_{.}^{\circ}$|5 and shows a broad 4-d maximum centred near λ⊙ = 80| $_{.}^{\circ}$|5 of 0.04 meteoroids km−2 h−1 producing meteors of equivalent radio magnitude of +6.5 from a mean radiant at αg = 44| $_{.}^{\circ}$|9 ± 1| $_{.}^{\circ}$|1, δg = 25| $_{.}^{\circ}$|5 ± 1| $_{.}^{\circ}$|0. During the plateau of shower peak activity, the mass index of the stream reaches a minimum with s = 1.6–1.7. Contamination from another nearby shower (likely the Daytime Zeta Perseids) and/or sub-streams showing different orbits compared to the core of the stream is evident in the interval 60| $_{.}^{\circ}$|5 ≤ λ⊙ ≤ 71| $_{.}^{\circ}$|5. Similar contamination beyond λ⊙ = 84| $_{.}^{\circ}$|5 may be due to the Helion sporadic source. We also characterized the deceleration profiles for Daytime Arietid meteor echoes using several independent speed techniques including Fresnel pre-t0, Fresnel amplitude oscillation and time-of-flight speeds which together with modelling produced a best estimate for the stream's out-of-atmosphere speed of v∞ = 40.5 ± 0.7 km s−1. The mean radar orbit from our study is noticeably smaller in semi-major axis and eccentricity than is found for larger Arietids measured with optical systems, a difference which if real indicates a particle-size sorting of the stream orbit. The broad activity maximum, long duration of activity and particle-size dependence of the orbital elements suggest the stream is too old to have been solely formed during the breakup of the parent comet of the Marsden sunskirters about a millennium ago as proposed by Sekanina & Chodas.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.