Fragmentation of specular overdense meteor trail echoes observed with Gadanki MST radar

• Published in: Astrophysics and space science Vol. 361; no. 2; pp. 1 - 8
• Main Authors: Chenna Reddy, K., Yellaiah, G.
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.02.2016; Springer Nature B.V
• Subjects: Amplitudes; Astrobiology; Astronomy; Astrophysics; Astrophysics and Astroparticles; Cosmology; Echoes; Fluctuations; Fragmentation; Light; Light curve; Meteoroids; Meteors; Meteors & meteorites; Observations and Techniques; Original Article; Physics; Physics and Astronomy; Pulsation; Radar; Radar systems; Scattering; Space Exploration and Astronautics; Space Sciences (including Extraterrestrial Physics; India, Andhra Pradesh, Gadanki; Meteoroid; Light curve—fragmentation; Specular overdense echoes
• ISSN: 0004-640X; 1572-946X
• DOI: 10.1007/s10509-016-2670-y

The pulse-integrated signal to noise ratio as a function of time known as radar meteor light curve (analogous to optical light curve), is an indicative of ablation processes during meteoroid flight in the atmosphere. In this study, we present and discuss few examples of light curves of long duration specular overdense meteor echoes detected with 53 MHz Gadanki ( 13.5 ∘ N , 79.2 ∘ E ) MST radar. These echoes are of several seconds duration, where pulsation in amplitude is about ten cycles within few seconds. This means the fluctuations in amplitude are much slower than typical Fresnel oscillations of underdense as well as the head echo fluctuations. These light curves reveal several features unreported previously in the radar meteor returns that are consistent with meteoroid fragmentation. Some of them provide the strong observational evidence of a sub-millimeter-sized meteoroid, breaking apart into two distinct fragments. The pulsations in light curves are interpreted as being due to interference from two distinct scattering centers. Some other meteor events such as meteoroids undergoing quasi-continuous disintegration are also discussed.