Dust from Comet 209P/LINEAR during its 2014 Return: Parent Body of a New Meteor Shower, the May Camelopardalids

TL;DR

This study observed comet 209P/LINEAR during its 2014 return, identifying it as the parent body of the May Camelopardalids meteor shower, and analyzed its dust ejection properties and activity levels.

Contribution

It provides detailed measurements of dust ejection, activity, and particle sizes of comet 209P/LINEAR during its dormant phase, linking it to a new meteor shower.

Findings

Particles up to 1 cm were ejected with velocities of 1-4 m/s.

The comet's activity was minimal, with a mass loss rate of 2-10 kg/s.

Approximately 5x10^7 kg of dust was released during the 2014 return.

Abstract

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.