  We report a new observation of the Jupiter-family comet 209P/LINEAR during
its 2014 return. The comet is recognized as a dust source of a new meteor
shower, the May Camelopardalids. 209P/LINEAR was apparently inactive at a
heliocentric distance rh = 1.6 au and showed weak activity at rh < 1.4 au. We
found an active region of <0.001% of the entire nuclear surface during the
comet's dormant phase. An edge-on image suggests that particles up to 1 cm in
size (with an uncertainty of factor 3-5) were ejected following a differential
power-law size distribution with index q=-3.25+-0.10. We derived a mass loss
rate of 2-10 kg/s during the active phase and a total mass of ~5x10^7 kg during
the 2014 return. The ejection terminal velocity of millimeter- to
centimeter-sized particles was 1-4 m/s, which is comparable to the escape
velocity from the nucleus (1.4 m/s). These results imply that such large
meteoric particles marginally escaped from the highly dormant comet nucleus via
the gas drag force only within a few months of the perihelion passage.
