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

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• 作者：K. Chenna Reddy ; G. Yellaiah
• 关键词：Specular overdense echoes ; Meteoroid ; Light curve—fragmentation
• 刊名：Astrophysics and Space Science
• 出版年：2016
• 出版时间：February 2016
• 年：2016
• 卷：361
• 期：2
• 全文大小：990 KB
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• 作者单位：K. Chenna Reddy (1)
  G. Yellaiah (1)
  
  1. Department of Astronomy, Osmania University, Hyderabad, 500007, India
  
• 刊物类别：Physics and Astronomy
• 刊物主题：Physics
  Astronomy
  
• 出版者：Springer Netherlands
• ISSN：1572-946X

文摘

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 (\(13.5^{\circ}N\), \(79.2^{\circ}E\)) 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.