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 r _ { h } = 1.6 au and showed weak activity at r _ { h } \leq 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 \pm 0.10 .
We derived a mass loss rate of 2–10 kg sec ^ { -1 } during the active phase and a total mass of \approx 5 \times 10 ^ { 7 } kg during the 2014 return .
The ejection terminal velocity of millimeter- to centimeter-sized particles was 1–4 m sec ^ { -1 } , which is comparable to the escape velocity from the nucleus ( 1.4 m sec ^ { -1 } ) .
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 .