Characteristics of very faint (+16) meteors detected with the Middle Atmosphere ALOMAR Radar System (MAARSY)

In September/October 2016 a dedicated specular meteor trail experiment with the high-power, large-aperture MAARSY radar was conducted, combining the high-power density of the radar with the large scattering target of trail echoes with the goal of probing the population of very small, slow-moving meteoroids. In contrast to meteor head echo observations, we find our raw velocity distribution peaks around 19 km/s for meteoroids with a limiting radar magnitude of +16. The correction for different observing biases to an equivalent limiting mass leads to a peak in the meteoroid influx at 13 km/s. Our calculated meteoroid masses range from 10(-11) to 10(-7) kg. Using an ablation model we show that our detections are near the micrometeorite ablation limit at low speeds. A tentative comparison with a Jupiter Family Comets (JFC) dynamical meteoroid model shows an apparent excess of large, slow meteoroids not predicted by the model.