Latitudinal difference in meteor trail ionization heights and identification of meteor showers
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ORIGINAL ARTICLE
Latitudinal difference in meteor trail ionization heights and identification of meteor showers K. Chenna Reddy1
· B. Premkumar1 · G. Yellaiah1
Received: 2 August 2019 / Accepted: 2 November 2019 © Springer Nature B.V. 2019
Abstract The ionization heights of meteor trails are strongly dependent on local atmospheric conditions in the mesosphere and lower thermosphere (MLT)-region. We present here latitudinal difference in ionization heights of meteor trails at two distinct latitudes, Thumba (8.5◦ N, 77◦ E), India and Eureka (80◦ N, 85.8◦ W), Canada. There is a large seasonal variation in meteor count at high latitude as compared to low latitude. Similarly, there is a large variation in meteor trail ionization heights at high latitudes, but not at low latitudes. However, it noticed that the trail ionisation heights at low latitude are found to be about 2 km higher. The latitudinal differences are probably related to changes in electron line densities at local MLT-regions. The identification of meteoroid streams in the sporadic background is still a noteworthy problem to pursue. By considering ionisation heights of meteor trails as a simple but robust metric, we identified shower meteors from the background sporadic activity, as the ionization heights of shower meteors are different from the sporadic meteors. We apply this shower detection technique on long-term data set at two different latitudes and compared with existing shower calendars. By using the median height of meteor trails and their corresponding upper and lower quartiles (Uq and Lq) as a metric, we unambiguously identified all northern hemisphere showers with a zenithal hourly rate larger than 20, which are in good agreement with the known showers. Keywords Meteor trail ionization heights · Meteor showers · Meteoroid properties
B K. Chenna Reddy 1
Department of Astronomy, Osmania University, Hyderabad, 500007, India
1 Introduction It is well known for the past several decades that a meteor can be a source of ionization in the Earth’s upper atmosphere (Herlofson 1947; Lovell 1954). Meteor ionization takes place when meteoroid, a solid dust particle of interplanetary origin, enters the Earth’s atmosphere at velocities anywhere between 11 and 72 km/s (Cziczo et al. 2001). Due to high energetic collision of meteoroid with surrounding air molecules causes its surface temperature rises rapidly about 2000 K, so that the surface particles start to evaporate by leaving behind a linear trail of ionized gas and dust in its path at the height range between 70 and 120 km (Bronshten 1983; Love and Brownlee 1991). When a radar beam of suitable frequency pointed perpendicular to this ionized trail, known as meteor trail, a strong scattering is obtained, and can be detected by the radio techniques (Ceplecha et al. 1998). The trail thus formed is a very thin and long parabola with meteor at its head. A typical trail width is just few meters, but the mean trail length may be about 25 to 30 km (Manning et al. 1953). The interplanetary dust particles come
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